Délivré Par

Présentée Par

Paolo Prosperi

Professeur M Gianluca Brunori

M Stephen

Professeur Jean-Louis Rastoin

Martine Mme

Padilla

M Iuri

M Thomas

Universitá Degli Studi

D I Catania

Sede Amministrativa

Prof Carrà Giuseppina

Dott

Peri Iuri

Martine Prof

Anno Padilla

Accademico

An indicator-based vulnerability and resilience approach for the Mediterranean Region]

Keywords: Food systems, Food Security, Sustainability, Resilience, Mediterranean, Metrics Systèmes alimentaires, Sécurité alimentaire, Durabilité, Résilience, Méditerranée, Indicateurs. Chapter 2 Agricultural biodiversity, social-ecological systems

basées sur les approches de la vulnérabilité et de la résilience.

List of Figures

List of Tables

 Table 1:Advantages of a vulnerability approach……..……..……..……...

Thesis at a glance

Sustainability of food systems: A Social-Ecological Systems Frameworks perspective

To describe the interest of the socialecological system frameworks for answering questions about the sustainability problems that affect the functions of the food system.

An extensive literature review was conducted, on problems related to food and nutrition security, and on SES frameworks approach to food systems dynamics.

The understanding of the food systems as SES proved helpful in answering questions on the sustainability problems of the food system. Theories of vulnerability and resilience are often adopted in research to understand the complex dynamics involving socioeconomic and biophysical aspects, and to implement sustainable development strategies.

Chapter 2 (Article I)

Agricultural biodiversity, social-ecological systems and sustainable diets: Towards resilience for food security

To describe food systems as complex social-ecological systems, involving multiple interactions between human and natural components.

An extensive literature review was conducted focusing on the interactions and mutual dynamics of change between nutritional patterns and environment structure.

Conceptual modeling frameworks are described articulating the synergies and tradeoffs between dietary diversity and agricultural biodiversity, and associated ecosystem functions that are crucial resilience factors to climate and global changes. The systemic nature of these interactions calls for multidimensional approaches, integrated assessments, and simulation tools to guide change.

Chapter 3 (Article II)

Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region

To develop a multidimensional framework for the analysis of the sustainability of diets and food systems, applicable to countries of the Mediterranean region.

A vulnerability / resilience approach has been adapted to analyze the main issues related to food and nutrition security, through causal factor analysis.

A conceptual framework was identified for modeling the relationships between food and nutrition security and sustainability, and developing potential indicators of sustainable diets and food systems.

Chapter 4 (Article III)

Modeling Sustainable Food Systems: A Dynamic System Approach

To define the main variables for the formalization and operationalization of the multidimensional concepts of sustainable food systems.

Building on SES frameworks theories of vulnerability and resilience, a dynamic system approach was adopted to model and mathematically represent the changing behavior of the food system variables over the time. A vulnerability / resilience assessment method was then applied.

A feedback-structured framework of the food system formalized eight causal models of vulnerability and resilience, shaping the interactions where a set of drivers of change affect a number of food and nutrition security outcomes, at a subregional level.

Chapter 5

Using Delphi expert elicitation survey to select indicators of Sustainable Food Systems

To identify metrics for assessing the sustainability of food systems and diets, building on the interactions between a set of biophysical and socioeconomic drivers of vulnerability and a number of context-specific FNS issues.

Building on a vulnerability / resilience theory-driven approach, an expert-based Delphi method was conducted in 3 rounds with feedbacks. The panel of experts counted, over each of the three rounds, 51, 39, and 36 participants.

Consensus on a reduced pool of indicators was obtained in the 75% of cases (18 indicators). It allowed validating a conceptual and dynamic framework for the food system, and identifying main metrics of reference, moving beyond subjective evaluation.

CIHEAM-IAMM. She enthusiastically convinced me about the interest and the challenge of observing the contradictory issues of food security, from different points of view and considering the sustainability of the food systems through innovative paradigms of analysis. She really encouraged me then to tackle these issues in a PhD thesis.

The first person that made this PhD possible is Iuri Peri, from the University of Catania, who was also strongly persuaded of the importance and the perspective of this topic and accepted to co-supervise this PhD with Martine Padilla in a joint international partnership.

I am thankful to both my supervisors for encouraging me in this work and always

showing me the right pathway for keeping a rigorous scientific approach, still guarantying my intellectual freedom. Furthermore, they constantly gave their institutional support allowing me assisting and presenting in a number of international events and conferences, organizing seminars and meetings in Catania and Montpellier, and entrusting me with responsibilities that permitted to further develop my skills. This gave me the opportunity to get experience in the international research environment.

I am much indebted in particular to Thomas Allen, who also encouraged me from the beginning to tackle a PhD, and then with whom I could strongly collaborate in the Bioversity International and CIHEAM-IAMM joint partnership. I could learn a lot from him and his advices, and our collaboration was key for the achievement of the results, and for learning how to work in a scientific team, writing articles, presenting and organizing workshops.

I am really grateful to Bruce Cogill who strongly believed and wanted to join efforts in a Bioversity International and CIHEAM-IAMM partnership, and who strongly contributed to focus the objectives of this common project. Thanks a lot also for participating in the steering committee.

I also am indebted to Foued Cheriet for having accepted to take part to the steering committee of the PhD and for having taken the time to advise me wisely.

I am thankful to the group of experts participating in the exploratory workshops before starting with the Delphi process, who contributed with valuable inputs to make the survey more suitable for the larger panel. I am really grateful to: Hatem Belhouchette, Bernard Fallery, Yves Martin-Prevel, Jean-Louis Rastoin, and George-André Simon.

Special thanks also to the large number of experts who participated in the Delphi survey, giving valuable contributions to the application of a scientific work and for being part of a community working on food security and sustainability of the food systems.

My sincere thanks to all the members of the jury for accepting to take part to the viva and to the not fore-mentioned members, Gianluca Brunori and Stephen Morse, for accepting also to act as rapporteurs.

I want also to express my gratitude to Amid Bencharif and Selma Tozanli for acknowledging my willing, during the Master degree, for doing research on food security. I am very grateful to Bénédicte Oberti for being involved with energy and having encouraged this PhD since the internship period and also for coaching me in the last days of preparation of the viva with Nadège Padilla-Renaud, whom I thank very much too for the kind and valuable advices. Sincere thanks to Vincent Dollé for having provided a strong institutional support from the beginning and to Pascal Bergeret who extended this institutional support from the CIHEAM-IAMM.

I am really grateful to Giuseppina Carrà for coordinating the PhD in Catania and always supporting the interest of this topic and the international scientific collaboration.

Special thanks to Cécile Adamolle, Dominique Poilleau, and Rafaele Sarrade of the Centre de documentation IAMM, for their kind help in providing bibliographic tools, advices and for always helping in finding interesting publications, and to the Centre de documentation Bartoli de Moïsa.

I am grateful to Isabelle Ferrier, Claire Rubio, Melanie Jacques (IAMM), and Anne-Cécile Leroux (Moisa) for their constant and kind assistance.

Many thanks to the PhD students and colleagues from Catania and Montpellier, and also to those from other Universities whom I have met in the several international meetings and activities all over these four years.

Thanks a lot to all my dearest friends in Montpellier and Rome, and those in London, Madagascar, Cameroun, Quebec, and wherever they are now, for supporting me with advices, patience and simply sharing time and experiences together.

Great thanks to my mother Stefania, my father Tommaso, my brother Marco, and to all our family for their inestimable support.

And in the end, thank you Camille … for all your support and for celebrating this and many other beautiful things of life together.

"Everyone has the right to a standard of living adequate for the health and well-being of himself and of his family, including food, clothing, housing and medical care and necessary social services, and the right to security in the event of unemployment, sickness, disability, widowhood, old age or other lack of livelihood in circumstances beyond his control."

The Universal Declaration of Human Rights, United Nations General Assembly, 1948.

"It is impossible to dissociate language from science or science from language, because every natural science always involves three things: the sequence of phenomena on which the science is based; the abstract concepts which call these phenomena to mind; and the words in which the concepts are expressed. To call forth a concept, a word is needed; to portray a phenomenon, a concept is needed. All three mirror one and the same reality."

Traité élémentaire de chimie, Antoine Laurent Lavoisier, 1789.

Chapter 1

Introductory chapter.

Sustainability of food systems: A Social-Ecological

Systems Frameworks perspective

-Background

The latest FAO estimates indicate that approximately 805 million people are chronically undernourished worldwide [START_REF] Fao | The State of food insecurity in the world: Strengthening the enabling environment for food security and nutrition[END_REF]. Considering that the global population is projected to reach 7,3 billion in 2015 (UN, 2014), it is possible to estimate that 11% of people are chronically undernourished [START_REF] Fao | The State of food insecurity in the world: Strengthening the enabling environment for food security and nutrition[END_REF].

Concurrently, nearly 2.1 billion people are affected by malnourishment related to unhealthy food consumption and dietary trends, which is reflected in the spread of food-related diseases like obesity and nutrient deficiency [START_REF] Ng | Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: a systematic analysis for the Global Burden of Disease Study 2013[END_REF]. At the same time food production and consumption exert a huge impact on the environment and are significant sources of green house gases. Furthermore, agriculture is responsible for 70% of water withdrawal (FAOSTAT, 2012) and represents a main driver of deforestation and loss of biodiversity. Food systems rely on physical resources such as land, water, biodiversity, and fossil fuels which are becoming ever more fragile and scarce. Efforts, therefore, need to be focused on the creation of food systems that are more efficient in the use of resources and reduce food waste, at every stage, from primary production to transformation and consumption (UNEP, 2012).

Food insecurity is a persisting global issue and the food system is now facing a new set of intersecting social, environmental, and economic challenges. Food security depends essentially on ecosystems and their services and during the last 50 years the physical and functional availability of ecosystem services has fallen faster than ever before (IAASTD, 2009). Presently Earth's life support systems encounter a condition of serious depletion and human development will be confronted with rising resource shortage (MEA, 2005).

The leading tenet related to food insecurity issues focuses on improving access to adequate food for those who suffer from hunger and malnutrition, and on increasing supply by 70-100% -through agricultural intensification -in order to feed a growing human population confronted with rising incomes, urban transition and changing dietary preferences (FAO, 2009;[START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. A number of common policy strategies have been encouraged to foster sustainable food security and consist mainly of closing yield gaps, improving resource efficiency and production limits, changing consumption trends, banning agricultural expansion and cutting waste [START_REF] Godfray | Food security: the challenge of feeding 9 billion people[END_REF][START_REF] Foley | Solutions for a cultivated planet[END_REF].

Global environmental change -apparent in climate change, ocean acidification, and biodiversity loss -has a growing impact on stocks and flows of ecosystem services at a global level (Ingram et al., 2010). Evidences related to this global change are observed through worldwide-reduced yields that are severely affecting food security [START_REF] Lobell | Nonlinear heat effects on African maize as evidenced by historical yield trials[END_REF]. Besides environmental change, numerous socio-economic factors bear critical responsibilities in food systems and drive outcomes of food security (Ericksen, 2007).

Food and nutrition security as main outcome of an integrated food system

"Food Security" was defined -in the 1996 World Food Summit (United Nations) -as the state that "exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life". Food and nutrition security is underpinned by food systems [START_REF] Ingram | Priority research questions for the UK food system[END_REF] and relies on several properties of food systems, categorized as a range of activities -producing, processing and packaging, distributing, retailing and consuming -that emanate in three main sets of outcomes, namely: food and nutrition security, social welfare and environmental capital.

Furthermore, various elements of food systems are altered by, and actively impact, the socioeconomic and environmental conditions of the system across local, regional and global levels. These interactions are featured by -and bring with themselves high uncertainties (Ericksen, 2008a;Ingram et al., 2010;[START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF] (Figure 1).

Figure 1 -Food system framework (Ericksen, 2008a) Food and nutrition security then is considered the principal outcome of any food system (Ericksen, 2010) and is a multidimensional concept that can be analyzed at individual, household, community, national, regional and global level [START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF].

Fulfilling the food demand remains challenging because of the disturbances brought by global environmental change. The food system is partially responsible for these changes through its own activities, which in turn hamper the availability of resources for sustaining the perpetuation of the food system functions [START_REF] Misselhorn | A vision for attaining food security[END_REF].

In order to link these different challenges, and, building on a broad definition of food system, food security can be deemed as the outcome of several different activities.

This perspective allows Ericksen (2007) to suggest a social-ecological system (SES)

approach for the analysis of the food system, incorporating environmental, social, political and economic determinants summarized in socioeconomic and global environmental change drivers [START_REF] Gerber | Food Security as an Outcome of Food Systems[END_REF]. Thus, food systems are considered social-ecological systems that comprise biophysical and social factors linked through feedback mechanisms [START_REF] Berkes | Navigating social-ecological systems: building resilience for complexity and change[END_REF]Ericksen, 2008a) (Figure 1). Food insecurity, therefore, arises when multiple biophysical, economic and social stresses (strongly linked to global environmental change) negatively impact, individually or concurrently, on different aspects of the food system [START_REF] Ingram | Priority research questions for the UK food system[END_REF][START_REF] Ericksen | Vulnerability of Food Security to Global Change[END_REF]. These multiple pressures converge on the major determinants of food security, namely supply, access and utilization [START_REF] Misselhorn | A vision for attaining food security[END_REF].

Global food security is facing several challenges, and there are key elements that might support a successful food system. The global food system is changing fast and in the meantime is being confronted with surrounding global socio-political and ecological changes [START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF], however, human societies have the ability to anticipate and modify these changing trends [START_REF] Holling | The backloop to sustainability[END_REF].

Together with global environmental change, increasing economic and social inequalities, market and political instability, and shifting consumption patterns hamper the global food system, with consequences such as the double burden of malnutrition [START_REF] Garrett | Stunted child-overweight mother pairs: An emerging policy concern?[END_REF]. Depletion of ecosystem services, the loss of freshwater resources and soil erosion contribute to further threaten the capacity of humans to fulfill their nutritional needs (MEA, 2005;[START_REF] Carpenter | Scenarios for ecosystem services: an overview[END_REF]. The world population is growing rapidly and diets are shifting towards an increasing demand for meat products. Concurrently modern agriculture still depends on oil coming from fossil reserves and biofuel production (Ericksen, 2008a;[START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF]2012). These evidences show the crucial contradictions and challenges that the food system is facing. There is an urgent need for developing knowledge-based tools to assess and monitor sustainability of food systems and to identify pathways for food security and resource conservation.

Generally, agricultural and resource management problems are categorized as classic system problems. Similarly to food systems, aspects of systems behavior are complex and difficult to anticipate and causes are multiple. In natural and social systems, and their interplays, problems are often non-linear, dynamic, and cross-level in time and space. It is thus necessary to have one system-perspective where feedbacks occur across temporal and spatial scales. In order to explore and identify the appropriate strategies of response to the interactions in a changing coupled human-environment system in relation to food and agriculture, interdisciplinary and integrated analysis methods are needed [START_REF] Ericksen | Assessing the Vulnerability of Food Systems to Global Environmental Change: A Conceptual and Methodological Review[END_REF][START_REF] Thompson | Agri-food System Dynamics: pathways to sustainability in an era of uncertainty[END_REF]. Since systems approaches focus on the dynamic interactions among different components, they are necessary for understanding the non-linear mechanisms through which global environmental change impacts not only on agricultural production but also on economic, cultural, and other factors [START_REF] Ericksen | Vulnerability of Food Security to Global Change[END_REF].

Scientific analyses of contexts, systems and their properties inform the political process on how to achieve sustainability, and diversification of knowledge, integration of methods and inclusiveness in decision-making and governance are key [START_REF] Scoones | Dynamic Systems and the Challenge of Sustainability[END_REF]. For the food system, the potential answers can be found in the analyses of the quantitative nexuses between diets, the environment and human health, through the contribution of nutritionists, agriculturists, public health professionals, educators, policy makers and the food industry sector [START_REF] Tilman | Global diets link environmental sustainability and human health[END_REF]. In such a dynamic scenario, measures of food and nutrition security that only focus on outcomes, such as hunger and malnourishment, might be too narrow for a comprehensive understanding of the food system and its changing causal mechanisms. However there are presently no precise and reliable global common metrics in use to measure the sustainability of food systems [START_REF] Vinceti | The contribution of forests and trees to sustainable diets[END_REF].

There is a call for multidisciplinary and more inclusive, social-ecological, systemoriented approaches that look at the resources (financial, physical, natural, and social) to capture the dynamic processes between and within the food system activities, nutrition and health, and environmental outcomes [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF].

1.2 -Social-Ecological Systems Frameworks [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF] comprehensively synthetize what is generally intended by the term 'Social-Ecological System' (SES): "SES visualizes the human-environment interface as a coupled 'system' in which socio-economic as well as biophysical driving forces interact to influence food system (and sub-system) activities and outcomes, both of which subsequently influence the driving forces". SESs are dynamic systems that are continuously changing in response to internal or external pressures [START_REF] Berkes | Linking social and ecological systems for resilience and sustainability[END_REF]Schluter, 2014) and the literature concerned was initially oriented mostly towards environmental change and the medium-and long-term impacts of human activities on future human prosperity (Foran et al.,214). Furthermore, most complex phenomena involving concurrently social and ecological systems are indivisible and any differentiation is thus considered counterfeit and subjective [START_REF] Berkes | Linking social and ecological systems for resilience and sustainability[END_REF]. SESs involve societal (human) and ecological (biophysical) subsystems in mutual interaction [START_REF] Gallopín | Linkages between vulnerability, resilience, and adaptive capacity[END_REF].

Food system as a Social-Ecological System

Food systems are a form of complex social-ecological system [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF] spanning the biological and socioeconomic processes encompassed in the production, distribution, marketing, preparation, and consumption of food [START_REF] Misselhorn | A vision for attaining food security[END_REF].

Building on Roe's method (1998) of triangulation of conceptual frameworks, [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF] picked a set of four dissimilar groups of conceptual frameworks oriented towards a rigorous analysis of the complexity in food systems in order to improve interdisciplinary interactions and the understanding and interventions in food security dynamics. This comparative analysis involved the conceptual framework groups of Agroecology, Agricultural Innovation Systems, Social-Ecological Systems and Political Ecology. The authors observed that the SES frameworks emerge within the other sets with respect to problem framing. In fact, SES frameworks highlight crosslevel and cross-domain interactions in a system, while the other sets of frameworks opt rather for focusing on a particular domain or level. The SES frameworks arise as system-oriented frameworks that give further priority to complexity, analysis of systemic interactions and problem identification [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]). In addition, from this analysis it is possible to observe that the SES frameworks appear to further emphasize the understanding of the relationships and the behavioral conditions of food systems faced with global change.

Alternatively, [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF] These conceptual frameworks were identified to allow an organized and interdisciplinary reflection on the complex issues in social-ecological systems, however, with regards to contextual and structural criteria, it is possible to find critical divergences within these frameworks, especially for the conceptualization of the ecological and social systems and their interconnections [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF]. The conceptual frameworks were classified throughout their contextual and structural characteristics into four groups: Ecocentric, Integrative, Policy and Vulnerability frameworks. The SES framework is thus considered an Integrative Framework since, consistently with [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF], it deems the mutuality between the social and the ecological systems and comprehends various types of feedbacks loops within the social system and between the social and ecological systems in different time scales.

Significantly, as demonstrated by [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF] the SES framework approach emerges among the other frameworks as potentially the best candidate for gathering and diffusing pertinent data on the social and ecological systems to be applied in any framework, and as a common research approach for interdisciplinary analyses of social-ecological systems with the precise goal to tie together disciplinary and methodological bounds [START_REF] Epstein | Missing ecology: integrating ecological perspectives with the social-ecological system framework[END_REF]. For several years now a vast community of scholars has gathered knowledge to make the SES framework a common classificatory framework for enhancing the understanding of complex socialecological systems through multidisciplinary efforts [START_REF] Ostrom | A General Framework for Analyzing Sustainability of Social-Ecological Systems[END_REF][START_REF] Epstein | Missing ecology: integrating ecological perspectives with the social-ecological system framework[END_REF]. In fact, the SES framework approach is widely considered as unique in its treatment of social and ecological systems in equal depth and its ability to offer a structure for developing several levels of specificity by discerning diverse tiers [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF].

Initially the SES framework originates from literature on ecosystem management and ecology and has strongly contributed to adaptation to global environmental change reasoning of natural resource management [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. The SES framework embodies the theories of resilience and vulnerability [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF] and in the last decade it has been usefully applied to food systems (Ericksen, 2007;Ingram et al., 2010).

It is assumed that a SES frameworks perspective for enlightening food security would lead to enhanced resilience in various specific food systems domains, through increased knowledge of systemic interactions, institutional transformation, diversity and connectivity between sub-systems (Ingram et al., 2010;[START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF].

Several investigations, from different discipline perspectives, were led on food and nutrition security through the lens of vulnerability. Socioeconomic studies find the causes of vulnerability, at both the level of the individual and at various group levels, mainly in socioeconomic and political factors [START_REF] Gorton | Environmental influences on food security in high-income countries[END_REF]. Other studies focus on impacts of and responses to environmental change, floods and droughts in vulnerable regions, and the connection to governance, inequality problems and physical and social geography factors [START_REF] Ericksen | Food security and global environmental change: emerging challenges[END_REF][START_REF] Eakin | What is Vulnerable?[END_REF][START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF][START_REF] Misselhorn | Vulnerability to what[END_REF].

Defining vulnerability and resilience of a food system

Over the last quarter of a century a host of efforts, mainly from agricultural sustainability studies, have been oriented towards the ability of food systems to absorb stress while keeping their original functions [START_REF] Conway | A doubly Green Revolution: ecology and food production[END_REF]Conway & Barbier, 1990;[START_REF] Thompson | Agri-food System Dynamics: pathways to sustainability in an era of uncertainty[END_REF]. Consistently, [START_REF] Misselhorn | A vision for attaining food security[END_REF] state that a resilient food system enhances food security and is able to minimize, withstand and anticipate environmental and economic disturbances at different temporal and spatial levels. In addition [START_REF] Berkes | Navigating social-ecological systems: building resilience for complexity and change[END_REF] and [START_REF] Gunderson | Panarchy: understanding transformations in systems of humans and nature[END_REF] find that shocks and perturbations potentially represent opportunities for innovation and transformation. On the other hand, a food system is considered vulnerable when it fails in delivering one ore many of its intended outcomes, because of even small stresses that might bring to significant social-ecological consequences [START_REF] Adger | Vulnerability[END_REF]Ericksen 2008a;Ericksen, 2008c;[START_REF] Eakin | What is Vulnerable?[END_REF].

Vulnerability -as the propensity or predisposition to be adversely affected (IPCC, 2014) -of a food system is a function of exposure, sensitivity and adaptive capacity [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Ericksen | The value of a food system approach[END_REF] and food systems can be vulnerable, and resilient, to a set of stressors [START_REF] Adger | Vulnerability[END_REF]) such as environmental pressures, socioeconomic instabilities and institutional and policy factors (Figure 2). [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] Therefore the analysis of the vulnerability of a geographical area needs to take into account the complex spatial and temporal interconnectedness and feedbacks that govern the achievement of the outcomes (supply, access, utilization) of all the activities and steps contributing to food and nutrition security [START_REF] Eakin | What is Vulnerable?[END_REF].

The concept of vulnerability has been adopted and largely explored in several disciplines and from various scientific communities referring to ecology, public health, human development, natural disaster, climate change and global environmental change, livelihoods security, sustainability science and risk and resilience [START_REF] Adger | Vulnerability[END_REF]Fussel, 2007;[START_REF] Cordell | Phosphorus vulnerability: a qualitative framework for assessing the vulnerability of national and regional food systems to the multidimensional stressors of phosphorus scarcity[END_REF]. Vulnerability assessment belongs generally to a context and an area of study defined by natural or artificial boundaries [START_REF] Downing | Assessing vulnerability for climate adaptation[END_REF]Schroeter et al., 2005) (Figure 2). Except for broad assessments of vulnerability to global environmental change (Rockstrom et al., 2009), climate change vulnerability is generally analyzed at a regional and local level since vulnerability is strongly context-specific. An assessment method could be appropriate in one region but inadequate in another area [START_REF] Cordell | Phosphorus vulnerability: a qualitative framework for assessing the vulnerability of national and regional food systems to the multidimensional stressors of phosphorus scarcity[END_REF].

Resilience, closely related to vulnerability in social-ecological systems, implies concepts of adaptation, transformation, innovation, self-organization and the capacity to perpetuate the activities over time despite the occurrence of stressors [START_REF] Adger | Vulnerability[END_REF][START_REF] Cutter | A place-based model for understanding community resilience to natural disasters[END_REF][START_REF] Folke | Resilience: The emergence of a perspective for social-ecological systems analyses[END_REF]. Resilience is a characteristic of complex and interrelated social-ecological systems that provides the system with the ability to absorb perturbations and also with the capacity to benefit from change through generating opportunities for development and innovation (Rockstrom, 2003;[START_REF] Adger | Vulnerability[END_REF]Resilience Alliance, 2010).

Vulnerability of the food system to global change

Contemporary food systems are characteristically cross-level and cross-scale [START_REF] Liverman | Why regions?[END_REF], and rely on a large set of biophysical and socioeconomic factors. Food and nutrition insecurity is the final result of a number of interactions between the global environmental change impacts on the food system and various socioeconomic dynamics. The effects of these interactions are observed in given exposed areas or populations. A sustainability perspective and a multidisciplinary analysis help to explore the complex interconnectedness of the economic, social and environmental aspects of the food systems in order to inform decision-making on the critical challenges of food insecurity and strengthen sustainable and resilient livings for present and future generations [START_REF] Misselhorn | A vision for attaining food security[END_REF].

In recent vulnerability analyses, climate change is one of the most studied topics.

Since the early 1990s numbers of scientific studies concerning climate vulnerability have increased regularly over time [START_REF] Adger | Social vulnerability to climate change and the architecture of entitlements[END_REF][START_REF] Kelly | Theory and practice in assessing vulnerability to climate change and facilitating adaptation[END_REF][START_REF] Klein | Assessment of coastal vulnerability to climate change[END_REF][START_REF] Tegart | Climate Change: The IPCC Scientific Assessment[END_REF]. In recent years, investigations have advanced by incorporating social vulnerability to climate change and adaptive capacity [START_REF] Ericksen | Using multiple knowledge systems: benefits and challenges, Chapter 5, Ecosystems and Human Well-being: Sub-global[END_REF]Fussel & Klein, 2006;[START_REF] Parry | Climate Change 2007: Working Group II-Impacts, Adaptation and Vulnerability[END_REF]Schroeter et al., 2005;[START_REF] O'brien | Vulnerable or resilient? A multiscale assessment of climate impacts and vulnerability in Norway[END_REF][START_REF] Cordell | Phosphorus vulnerability: a qualitative framework for assessing the vulnerability of national and regional food systems to the multidimensional stressors of phosphorus scarcity[END_REF]. As mentioned above, the impacts of climate change interplay with other changing dynamic mechanisms belonging to different economic, political, temporal and biophysical domains (such as poverty, gender inequality, food price increases and natural resources depletion) on a local, regional and global scale [START_REF] Ericksen | Food security and global environmental change: emerging challenges[END_REF].

Implementing linear policies becomes difficult in such uncertain dynamic conditions [START_REF] Funtowicz | Science for the post-normal age[END_REF][START_REF] Kriegler | The need for and use of socio-economic scenarios for climate change analysis: a new approach based on shared socio-economic pathways[END_REF][START_REF] Van Der Sluijs | Combining quantitative and qualitative measures of uncertainty in modelbased environmental assessment: the NUSAP system[END_REF]Vervoort et al., 2014).

From a social-ecological systems perspective where the simultaneous occurrence of several nature-and human-related drivers of change (such as climate change, natural resources depletion, habitat loss and pollution, shifting dietary patterns, financial speculation on food commodities, and oil extraction) threaten the ability of a global food system to maintain its vital functions and processes, food security is a global scale issue, from the North to the South [START_REF] Brunori | Security for whom? Changing discourses on food in Europe in times of a global food crisis[END_REF][START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF]. The drivers of change affecting the food system can be identified in five main categories, namely: environmental, economic, social, technological and political [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

Despite the importance of the various specific interactions between a number of global and regional drivers of change and context-related food and nutrition security issues, it is still necessary to stress the role of climate change as main environmental driver of global change that affects agricultural production and food security through unattended biophysical shocks [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. Global environmental change implies transformations in the physical and biogeochemical environment from both natural and human origins such as deforestation, fossil fuel consumption, urbanization, land fill, agricultural intensification, freshwater withdrawal, fisheries exploitation and waste production (Liverman & Kalapadia, 2010). Greenhouse gas (GHG) emissions and changes in land use, engendered by food system activities, strongly contribute to climate change, however these activities appear responsible for other aspects of global environmental change as well such as alteration of freshwater quality and supply, biodiversity, land cover and soils, nutrient cycling and air quality (Ingram et al., 2010). At a regional level it has been shown that climate change strongly contributes to major environmental concerns such as desertification, water stress, biodiversity loss, and soil degradation in the European Mediterranean area [START_REF] Van Ittersum | Current systems and future scenarios for food production activities[END_REF].

Furthermore, GHG emissions directly affect temperature, freshwater availability and numerous parameters of climate change. Climate change and natural resource depletion alter the world's food supply, and indirectly impact prices and quantities, and hence trade [START_REF] Godfray | Food security: the challenge of feeding 9 billion people[END_REF]Ingram et al., 2010), that in turn have serious impacts on food availability and affordability [START_REF] Wood | Lessons learned from international assessments[END_REF].

With specific regards to the food system human activities, the rate of agricultural land-use expansion over the last 60 years has substantially degraded biodiversity, topsoil, forests and water-quality (MEA, 2005). Increasing water shortages and extreme weather events are associated with yield reduction and instability, and a decrease in areas suitable for traditional crops [START_REF] Olesen | Climate change as a driver for European agriculture. SCAR-Foresight in the field of agricultural research in Europe[END_REF][START_REF] Olesen | Consequences of climate change for European agricultural productivity, land use and policy[END_REF], phenomenon that as been reported likely to occur in the European Mediterranean region [START_REF] Schröter | Assessing vulnerabilities to the effects of global change: an eight step approach[END_REF]Metzger et al., 2006).

Both climate and non-climate drivers affect food systems. For instance, non-climate drivers such as urbanization and pollution, and other socio-economic processes (including land-management change) directly and indirectly influence socialecological systems [START_REF] Parry | Climate Change 2007: Working Group II-Impacts, Adaptation and Vulnerability[END_REF]. Globalization, trade internationalization and a plethora of global forces, such as changes in demographic, economy, politics and environment, transform food production and consumption patterns including marketing influence many food-related context-specific practices [START_REF] Oosterveer | Food, globalization and sustainability[END_REF].

Almost all food systems in a global food system threaten the ability of Earth to provide food in the future. For this reason these food systems are not considered to be sustainable. Food production in Europe is closely outstripping the regional and global environmental breaking points, particularly with regards to nitrogen synthesis, phosphorus use, land use and degradation, and the dependence on fossil energy.

Within the same context, agriculture and fisheries are the largest drivers of biodiversity loss and water extraction [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. These critical environmental outcomes reveal that the future of food availability is closely related to the society's capacities in providing appropriate technologies and practices to sustain the productivity of the natural assets and compensate the ecosystem services degradation [START_REF] Eakin | What is Vulnerable?[END_REF]. Broadly considering that the exacerbation of the habitat loss has effects on poverty, international trade, finance and investments, and political equilibriums makes evident that this change jeopardizes not only food supply but also global stability and human development. Then, sufficient and nutritious food will be less affordable for disadvantaged groups of the population because of the concurrent occurrence of price volatility, interconnectedness of global commodity markets, increasing pressure of climate change on food production and loss of biodiversity [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. The 2007-2008 food crisis demonstrated the complex interlinkages of the food system with environmental, financial and energy crises, calling for interventions of mitigation [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

System processes imply that manifold interactive pathways of change and environmental feedbacks and social responses to a change or driver can generate further changes that resonate throughout social-ecological systems. This phenomena and perturbations are not entirely controllable or predictable (Ericksen, 2008c;[START_REF] Eakin | What is Vulnerable?[END_REF]. Thus, building on a wide understanding of food systems, the interactions between and within biogeophysical and human environments regulate a set of activities towards the achievement of the food security outcomes (availability, access, utilization), and these activities are consecutively altered by several factors [START_REF] Ziervogel | Adapting to climate change to sustain food security[END_REF][START_REF] Bausch | Agro-environmental sustainability assessment using multicriteria decision analysis and system analysis[END_REF]. Therefore, in a complex and adaptive system, for instance the European food system, food security outcomes are not possible to be forecasted by means of conventional command-and-control approaches. There is then a call for a deeper and common analysis of causality dynamics characterized by the complex interplay of socioeconomic, environmental, technological, and global political factors around the food system [START_REF] Ingram | Food system concepts for the ESF/COST Forward Look on European food systems in a changing world[END_REF]. Vulnerability and resilience of agri-food systems originate from several sources that interact to engender unpredictable responses, and system thinking is key to account for the interdependencies between drivers, feedback loops and non-linear trends [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

Food security and development practitioners work towards food security trying not to further compromise environmental and social welfares. Nevertheless they risk undermining ecosystem services through increasing the efficiency of food production (MEA, 2005). The aim thus is to build resilient food systems, achieving food security and trying to maintain desirable ecosystem states and services, despite global environmental pressures [START_REF] Folke | Social-ecological resilience and behavioural responses[END_REF][START_REF] Gunderson | Panarchy: understanding transformations in systems of humans and nature[END_REF][START_REF] Walker | A handful of heuristics and some propositions for understanding resilience in socialecological systems[END_REF]). To answer this necessity is key to close the gap in the understanding on the interactions among food security, vulnerability, resilience, and ecosystem services (Ericksen et al., 2008).

-Pertinence of the SES framework to the analysis of properties and interplays within contemporary food systems

The principal outcome of any food system is food and nutrition security. In particular food and nutrition security comprises the three components of availability, access and utilization. Food availability, or supply, is the amount, type and quality of food that a unit gets to consume. The access to food consists of the ability to acquire appropriate food and can be analyzed in terms of affordability, allocation and whether consumers can meet their food preferences. The utilization of food refers to the ability to consume and benefit from food [START_REF] Ericksen | The value of a food system approach[END_REF]. Nutritional security fully integrates this definition of food security since the available and accessible food has to be nutritious. The fulfillment of such food demand is jeopardized by global environmental change including climate, biodiversity, water availability, land use, tropospheric ozone and other pollutants, and sea level rise (Foresight, 2011;Ingram et al., 2010). As described above, these biophysical changes are generated also through food system activities and feedbacks on the environment that are further intensified by the coexistence of Global Environment Change (GEC) with competition for natural resources [START_REF] Molony | Biofuels, food security, and Africa[END_REF][START_REF] Misselhorn | A vision for attaining food security[END_REF][START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF]. For many years now various research studies have considered, from different perspectives, the vulnerability and resilience frameworks as some appropriate methodologies to find solutions to food security problems [START_REF] Alwang | Vulnerability: a view from different disciplines[END_REF].

These principles are still regarded as key to reconsider social research and social intervention policy approaches to food security [START_REF] Brunori | Security for whom? Changing discourses on food in Europe in times of a global food crisis[END_REF].

"Food security can only come from making food systems sustainable" [START_REF] Lang | Sustainable diets and biodiversity: the challenge for policy, evidence and behaviour change[END_REF].

To assess the sustainability of the food system -i.e. its capacity to maintain its essential functions/services over time [START_REF] Conway | Agroecosystem analysis[END_REF] (food and nutrition security being its principal outcome) -we need to understand what might affect its processes, to what extent the drivers of change (such as forces likely to affect the structure and the functions of a system) impact the food system outcomes (such as the activities along the value chains), and how actors respond to these pressures. Food security is at risk of an increasing number of dynamic constraints and drivers of change, and its multiple dimensions need to be holistically and systematically considered faced with these new challenges [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. Thus, a food system, together with its functions, is considered vulnerable to one or more stressors (such as economic shock, institutional instability, environmental change etc.) when it is not able to sustain food security (Ericksen 2008c).

Building on [START_REF] Eakin | What is Vulnerable?[END_REF], the whole food system is here conceptualized as a vulnerable entity and specific vulnerabilities are explored through analysis of the characteristic food system outcomes. Thus the "what is vulnerable" is identified in the capacity of a specific entity, providing ecological and social services, that is composed of a number of actors, activities and processes acting against the global drivers of change. The functions of the system will be considered vulnerable if negative food system-outcomes will emerge [START_REF] Eakin | What is Vulnerable?[END_REF]. For instance the current joint crisis of malnutrition and unsustainability originates from agricultural and food systems that do not provide sufficient essential nutrients for dietary requirements of people [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF]Graham et al., 2007;[START_REF] Declerck | Ecological approaches to human nutrition[END_REF]. As supported by a recent paper whose title literally states "Vulnerability of Food Security to Global

Change" [START_REF] Ericksen | Vulnerability of Food Security to Global Change[END_REF], we refer to the analysis of vulnerability and resilience, of an issue of the system, to a critical driver of change, with the aim of assessing the potential of the system to maintain its activity over time, and thus the likelihood of the sustainability of the system. Ericksen (2008c) suggests that vulnerability and resilience are inherent properties of the processes and activities of food systems, and also determine the responses to external and internal stressors occurring over time.

This analysis would help to elucidate how vulnerability is manifest in a food system, finding and anticipating the characteristic of the potential vulnerability and the adaptive behavior. One key conceptual element is a clear distinction between causal events and outcomes [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF]; a "causal factor approach" that describes the interactions leading to the final outcomes. This would allow a dynamic analysis of the particular issues of vulnerability, instead of a static identification of vulnerability to a broad and general final outcome [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF]. A broad understanding of vulnerability on a wide range of sectors or issues would not be sufficiently focused to implement actions [START_REF] Eakin | Assessing the vulnerability of social-environmental systems[END_REF][START_REF] Ionescu | Towards a formal framework of vulnerability to climate change[END_REF][START_REF] Luers | The surface of vulnerability: an analytical framework for examining environmental change[END_REF]. There is then a rising call for new types of systems analysis and modeling tools (Nicholson et al., 2009).

The integrated fragmentation of the broad vulnerability into specific vulnerabilities represents a response to the lack of causal factor analyses. Developing and applying this approach could provide empirical evidence contributing to a better understanding of the behavioral aspects of the food system (Ericksen, 2008c). This approach has already been used to elucidate dynamic feedback mechanisms characteristic of the food system providing a more detailed view of the food security issues and demonstrating that the various crises since 2007 (oil, food, financial and economic)

were interdependent. This provides the elements for anticipating and changing attitudes to risk [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. In particular, through this approach [START_REF] Ericksen | Global environmental change and food security[END_REF] prompts at describing the impact of environmental change on the food system within a socio-economic and political change, in order to identify the synergistic effects of this plethora of stressors interacting with the food systems and often leading to its vulnerability.

In the following sections a set of stressors, selected from the environmental, economic, social, technology and policy drivers mentioned above [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF], are analyzed (through literature review at European level) for their potential impact on a set of critical aspects of food and nutrition security, including availability, access and utilization issues, in a sort of interplay systemic mechanism that answers the question "what is vulnerable/resilient to what" in food systems.

Issues related to Water depletion

Nutritional quality

The loss of freshwater resources may affect the nutritional quality of food supply through the reduction of the production of specific nutrient-dense foods because of water scarcity, and also through utilization of low quality water sources because of both water shortage (and consequent low dilution) and water contamination. The nutritional characteristics of diets are directly related to environmental conditions [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF]. In fact agriculture affects health directly through its capacity to deliver a sufficient quantity of nutritious foods to consumers [START_REF] Dangour | Linking agriculture and health in low-and middle-income countries: an interdisciplinary research agenda[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF]. Meat production can necessitate several multiples of water (4000-15000 l/kg) than grain production (1000-2000 l/kg) [START_REF] Khan | Footprints of water and energy inputs in food production-Global perspectives[END_REF].

The state of greenhouse gas levels impacts rainfall, hampering water availability and quality. In turn, agrofood productivity impacts prices and quantities and hence trade and markets [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF][START_REF] Wood | Lessons learned from international assessments[END_REF]. Current water usage and management are driving toward food shortages. Global food production is increasingly dependent on rain, and climate change is reducing rainfall rates in many parts of the world.

Concurrent climate change, increasing demand and higher costs for water and fertilizers exacerbate the vulnerability of the agrofood systems and are affecting poorer consumers [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. Furthermore, global consumption of food has increased and projected population and socioeconomic growth will double food demand by 2050 (FAO, 2008). It has since been estimated that cereal yields will need to increase by 40% and net irrigation water requirements by 40-50% [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF] to meet this demand. If at international level, competition for water to guarantee the domestic food security of nations is increasing, at a sectorial scale there is a growing competition for water between agriculture, public water supply, industry and energy sectors, suggesting that insecurity in food supply may well become an issue in the future [START_REF] Bates | Climate change and water[END_REF][START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

More specifically, in some areas there is a shift from hydrological surplus to deficit;

the 'dilution' capacity of water is reduced, and the concentration of agrochemicals and soil nutrients increases. Furthermore, higher water temperatures will affect water quality and exacerbate many forms of water pollution (e.g. sediments, nutrients, pathogens, pesticides, salts) [START_REF] Bates | Climate change and water[END_REF][START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF] that will likely hamper human health through the contamination of agricultural product [START_REF] Parme | Quelles recherches et quels partenariats pour la Méditerranée?[END_REF].

Moreover, often farmers prefer using pesticides for increasing crop yields without considering the threat to a fundamental ecosystem service such as water resource [START_REF] Ericksen | The value of a food system approach[END_REF].

Access to food

Water scarcity and depletion may also affect the economic access to food, for instance through the impact of water pricing on food prices. It is widely acknowledged that GHG impact on precipitation quantity and frequency, affect productivity and in turn affect food availability and its quality [START_REF] Wood | Lessons learned from international assessments[END_REF]. For now, scarcity mechanisms, put in place to control the use of available water, comprise access limitations, either technological, legal or through pricing [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. It has been shown that increasing water prices (through financial support to guarantee water quantity and integrated river basin management to improve water-use efficiency)

inevitably lead to an increase in the cost of agricultural production, and therefore a potential decrease in food affordability [START_REF] Ingram | Stakeholders' Approaches to Regional Food Security Research[END_REF]. Regulating water utilization efficiency can have a considerable impact on biological, economic, and nutritional factors [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. Agrobiodiversity richness can contribute to contrast water scarcity and its indirect impacts, for instance through developing droughtresistant. Also focusing on food import from water rich countries can reduce the impact of water on food prices, whether the price of the external imported virtual water is lower than the internal one [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF].

Issues related to Biodiversity loss

Nutritional quality

The nutritional characteristics of diets are closely interlinked with the state of the environmental capital [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF]. The loss of biodiversity richness affects the availability of diverse necessary nutrients to food production. Indeed, agricultural production impacts on health directly through its potential in supplying adequate amounts of nutritious foods for consumers [START_REF] Dangour | Linking agriculture and health in low-and middle-income countries: an interdisciplinary research agenda[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF]. The quality of nutritional supply and human health is thus in danger because of a loss in biodiversity [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF]. Genetic diversity has declined globally, particularly among cultivated species (MEA, 2005) and biodiversity loss has detrimental effects on human nutrition as commonly available foods do not provide the adequate nutritional diversity required for sufficient intake of micronutrients by human beings. In fact, nowadays global food chains are homogenized for processing and delivering few species and varieties. Diversity and local species are neglected [START_REF] Khoury | Increasing homogeneity in global food supplies and the implications for food security[END_REF]; three crops alone (rice, wheat and maize) account for more than 55 % of human energy intake [START_REF] Stamp | Competitive underutilized crops will depend on the state funding of breeding programmes: An opinion on the example of Europe[END_REF]. Meanwhile the micronutrient superiority of some lesser known cultivars and wild varieties has been observed.

Recent research analyses have demonstrated that the pro-vitamin A carotenoid content fluctuate between banana cultivars from 1 µg to 8,500 µg/100 grams, betacarotene concentration can vary by a factor of 60 between sweet potato cultivars, and that the protein content of rice span from 5 to 13 per cent, depending on the variety [START_REF] Kennedy | Analysis of food composition data on rice from a plant genetic resources perspective[END_REF][START_REF] Burlingame | Food composition is fundamental to the cross-cutting initiative on biodiversity for food and nutrition[END_REF][START_REF] Lutaladio | Horticulture, biodiversity and nutrition[END_REF].

The focus on ecologically simplified farming systems, based on cereals, contributes to micronutrient deficiency, poorly diversified diets, and malnutrition in both developed and non-developed areas [START_REF] Frison | Agricultural biodiversity, nutrition, and health: Making a difference to hunger and nutrition in the developing world[END_REF]Graham et al., 2007;[START_REF] Negin | Integrating a broader notion of food security and gender empowerment into the African Green Revolution[END_REF][START_REF] Remans | Assessing Nutritional Diversity of Cropping Systems in African Villages[END_REF][START_REF] Welch | A new paradigm for world agriculture: meeting human needs: Productive, sustainable, nutritious[END_REF]. This increased reliance on domesticated species and selected crop varieties can be linked to a significant reduction in dietary diversity. Agricultural biodiversity is thus considered an essential component in the sustainable delivery of a more secure and nutritious food supply [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF]. Paradoxically the efforts accomplished to guarantee food supply, based on the exploitation of ecological services, hamper the ability of the ecosystems to deliver the essential nutrients for human diets [START_REF] Palm | Soils: a contemporary perspective[END_REF]. Nutritional diversity is now widely recognized to be a key factor for adequate diets likely to satisfy the complex human nutritional needs [START_REF] Who | Diet, nutrition and the prevention of chronic diseases, Report of a joint WHO/FAO expert consultation[END_REF][START_REF] Arimond | Simple food group diversity indicators predict micronutrient adequacy of women's diets in 5 diverse, resource-poor settings[END_REF][START_REF] Roche | Traditional food diversity predicts dietary quality for the Awajun in the Peruvian Amazon[END_REF][START_REF] Randall | Diet diversity and nutrient intake[END_REF][START_REF] Torheim | Nutrient adequacy and dietary diversity in rural Mali: association and determinants[END_REF][START_REF] Arimond | Dietary diversity is associated with child nutritional status: evidence from 11 demographic and health surveys[END_REF][START_REF] Pelletier | Changes in child survival are strongly associated with changes in malnutrition in developing countries[END_REF]. Recently, it has been evaluated that coastal and marine biodiversity contributes to the nutritional basis of 20 % of the world's population. Its loss represents a major risk of irreversible nutritional damage. Furthermore, loss of agrobiodiversity interacts with other food system stressors and thus makes food systems more vulnerable to climate change and to volatility in prices for energy, water and fertilizer, since globally privileged varieties are usually strongly dependent on external inputs. The impact of natural resources depletion and the decline of the recovery potential of the food system, based on the ecosystem services, will significantly shape the future of food and nutrition security [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF].

Plant and livestock genetic diversity is widely acknowledged for contributing to ecosystem services conservation and food and nutrition security issues through, in particular, supporting the viability of agricultural systems and long-term productivity, ecosystem cultural services, pest management, soil water retention and increased nutritional value of foods, vis-à-vis increasing global environmental and natural uncertainties [START_REF] Thrupp | Linking agricultural biodiversity and food security: the valuable role of agrobiodiversity for sustainable agriculture[END_REF][START_REF] Reidsma | Regional farm diversity can reduce vulnerability of food production to climate change[END_REF][START_REF] Eakin | What is Vulnerable?[END_REF]IAASTD, 2009;[START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF][START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

Cultural preferences

The loss of biodiversity may affect the satisfaction of cultural food preferences.

According to the EU-SCAR Foresight 2011, the loss of agrobiodiversity is considered one of the main drivers (amongst others such as price volatility, access restrictions and the interconnectedness of global commodity markets, as well as the increasing detrimental action of climate change on food production systems) that will make adequate food still more inaccessible to the poor.

Diets are complex combinations of different food items influenced by cultural and regional preferences [START_REF] De Ruiter | European dietary patterns and their associated land use: Variation between and within countries[END_REF]. In the agrofood system, it is acknowledged that crop mix is altered by climate change, and that the livelihood of producers and cultural traditions and preferences, which are strictly linked to regional varieties and diets, are at risk [START_REF] Liverman | Food systems and the global environment: An overview[END_REF]. Few global crop commodities and food products characterize the human preference for energy-dense foods [START_REF] Kearney | Food consumption trends and drivers[END_REF]Khoury et al., 2013) and the global trend consists of homogenizing food production instead of enhancing and keeping traditional food cultures [START_REF] Jacques | Monocropping cultures into ruin: the loss of food varieties and cultural diversity[END_REF]. Habitat depletion and biodiversity loss contribute to reduce the enormous amount of information on nutritional and health benefits of the foods, that shapes the cultural food preferences of people [START_REF] Kuhnlein | Indigenous peoples' food systems: the many dimensions of culture, diversity and environment for nutrition and health[END_REF].

Furthermore, monoculture and lack of diversity push food system failure (Wahlqvist & Meei-Shyuan, 2007). For instance, in public health terms, the worldwide maneuvered trends of human preference for energy-dense foods, built on limited global crop commodities and processed foods, is closely related to the increasing occurrence of non-communicable food-related diseases [START_REF] Kearney | Food consumption trends and drivers[END_REF][START_REF] Pingali | Westernization of Asian diets and the transformation of food systems: implications for research and policy[END_REF][START_REF] Van De Wouw | Genetic erosion in crops: concept, research results and challenges[END_REF].

Agrobiodiversity includes a series of social, cultural and ethical variables [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF]. Food intake variety is positively correlated with a sense of personal food security (Wahlqvist, 2003). The decreased food biodiversity, caused by the homogenization of the global diet, could result in the loss of unique and traditional foods [START_REF] Jacques | Monocropping cultures into ruin: the loss of food varieties and cultural diversity[END_REF]. For instance several scholars have observed that in remote bush communities, access to traditional foods cannot be met anymore with locally available wild food, and that local populations can only access more expensive food of far lower quality and cultural relevance [START_REF] Ericksen | The value of a food system approach[END_REF].

Know-how of preparing a more diverse diet can change consumption of different food products [START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF][START_REF] Termote | Eating from the wild: Turumbu indigenous knowledge on noncultivated edible plants, Tshopo District, DRCongo[END_REF]) and can provide resilience elements for satisfying cultural food preferences against biodiversity loss. Stimulating consumption habits that are sensitive to the impact of food crop choice on health is now critical [START_REF] Khoury | Increasing homogeneity in global food supplies and the implications for food security[END_REF].

Issues related to Price Volatility

Nutritional quality

Food price volatility may affect the nutritional quality in food supply through direct and indirect impacts such as feedback loops on production due to consumer demand [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. In particular, trade dynamics have a potential negative impact on food supply, especially in disadvantaged groups [START_REF] Cummins | Large scale food retailing as an intervention for diet and health: quasi-experimental evaluation of a natural experiment[END_REF][START_REF] Who | WHO European Action Plan for Food and Nutrition Policy 2007-5012[END_REF]. The links between productivity, prices and trade, and their impacts on food availability and affordability are widely acknowledged since food system prices, quantities exchanged and trade are closely associated with the state of greenhouse gas levels, temperature, rainfall and other surface climatic parameters that hamper food production [START_REF] Wood | Lessons learned from international assessments[END_REF]. Furthermore, there is a clear link between food prices and oil prices. The reason is that the present agricultural production, trade, processing, distributions and retail systems, and fossil fuels, are tightly coupled systems, and this is an important driver of the vulnerability of food provisioning (DEFRA, 2008;[START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. Hence, changes in international trade and agricultural policies can led to profound changes in the composition and availability of food supplies and can significantly affect food prices. At a global level it was observed that food prices were relatively stable until 2005 and increased significantly in 2008, with a multiplier of 3.2 times the rice basic price, 2.1 times the wheat price and 2.5 times the corn price [START_REF] Ifad | Food Price Volatility: How to help smallholder farmers manage risk and uncertainty[END_REF].

Access to food

The determinants of food affordability involve pricing policy, seasonal and geographical variations in price, ratio between local and external prices, and households' income and wealth levels [START_REF] Ingram | Food system concepts for the ESF/COST Forward Look on European food systems in a changing world[END_REF]. Food price volatility through market disruption may affect the capacity of vulnerable nations and populations to access healthy amounts of food. Price volatility has a considerable effect on food security since it impacts incomes and purchasing power [START_REF] Hlpe | Price volatility and food security: a report by the High Level Panel of Experts on Food Security and Nutrition of the Committee on World Food Security[END_REF]. This is linked to the income and employment conditions of people and also to dominant consumption patterns. Food access depends upon the affordability of adequate food, which itself is based on the income of the people and the prices prevailing in the market. Both of these variables fluctuate from year to year and food price volatility is considered one of the most relevant drivers altering food accessibility for the poor [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. In the context of food systems, prices, trade and productivity impacts are closely related to food affordability and availability [START_REF] Wood | Lessons learned from international assessments[END_REF]. Food prices and food affordability are paramount determinants of food choices, obesity and non-communicable diseases [START_REF] Lee | Monitoring the price and affordability of foods and diets globally[END_REF]. Studies carried out during the recent food price inflation have brought into discussion the capacity of certain social groups to access quality food once taken for granted [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. Increase in food prices is a global trend that affects especially the poorer social groups dependent on salaries and tightly connected to the rest of the economy (Von Braun, 2008). Even in European contexts these increases are likely to hamper access to desired and quality food (UK Cabinet Office, 2008). This phenomenon was manifest in the recent food price inflation (SCAR, 2008) since higher food prices tend to have negative impacts on consumer health directly affecting food intake (quality and quantity of affordable food) [START_REF] Regmi | Demand side drivers of global food security[END_REF].

Consumers normally attempt to cope with the crisis by modifying shopping strategies, for instance purchasing lower quality foods, as demonstrated by Italian consumers who reduced meat consumption and increased their consumption of pasta whilst also purchasing more of their food from discount grocery stores [START_REF] Brunori | Security for whom? Changing discourses on food in Europe in times of a global food crisis[END_REF]. Alternatively, resilience opportunities can be found in the capacity of shifting towards cheaper or locally available foods while meeting the same caloric and nutritional requirements. Countries can also implement food policies for diversifying supply sources through different strategies such as subsidies, food stamps or promoting diversity in food consumption patterns.

Issues related to trends of food consumption patterns

Nutritional quality

Food consumption patterns and trends have a direct and critical effect on food production patterns and overall food security (UNEP, 2012). In fact, food industry focus is to meet the needs of price and quality for the consumers. In turn, the nutritional characteristics of diets are directly related to environmental conditions, which are consequences of the production system associated with current food consumption patterns [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF]. Trends in consumption patterns involve the variety of diets, changing habits, the difference in food consumption between the rich and poor, and health gaps within social groups. Between 1963 and 2003 the available food consumption of meat and eggs increased worldwide respectively to 65% and 100% [START_REF] Kearney | Food consumption trends and drivers[END_REF]. The consequences of the nutrition transition, characterized by a stronger demand for cereals, simple sugars and an increase of meat and animal products consumption in low-and middle-income countries, impact food supply, its quality, and the related pressure on ecosystems, but also production, imports, and prices [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. These changing habits are also reflected in the consumption of food outside of the home and with increased consumption of industrially-produced highly processed foods with an often higher content in energy and fat [START_REF] Prentice | Fast foods, energy density and obesity: a possible mechanistic link[END_REF][START_REF] Who | WHO European Action Plan for Food and Nutrition Policy 2007-5012[END_REF].

Understanding the determinants of consumer choices can improve agricultural and food systems in delivering nutritious food, as well as the health of the consumer [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF]. A broader scientific understanding is necessary for influencing food choices towards healthier food habits and for informing consumers. At a supply chain level, the food industry and retail sector, as well as the media, play a key role in changing consumer patterns [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF]. A food system approach elucidates the interrelation of food production and processing, and food consumption patterns and nutritional outcomes [START_REF] Schubert | Explaining Patterns of Convenience Food Consumption[END_REF].

Dietary balance

Dietary energy balance is hampered by the shift towards particular food consumption and dominant lifestyles (increase in fats and sugars, decrease in plant proteins). These changes lead, as causal factors, to obesity and cardiovascular and nutrition-related non-communicable diseases such as heart disease, cancer, overweight and diabetes [START_REF] Parme | Quelles recherches et quels partenariats pour la Méditerranée?[END_REF], with the latter tripling in some developing countries (UNEP, 2012).

This trend towards industrially produced products and away from traditional foods is defined as "nutrition transition" [START_REF] Kuhnlein | Arctic indigenous peoples experience the nutrition transition with changing dietary patterns and obesity[END_REF][START_REF] Popkin | The nutrition transition: worldwide obesity dynamics and their determinants[END_REF], and comes at great economic, physical and psychosocial expense (Ingram et al., 2010). It is now widely assumed that the nutritional transition, allied to more sedentary lifestyles, is also driving obesity [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. Changes in global social systems are key as well in influencing diets through issues related to household livelihood and income and world population dynamics [START_REF] Mendez | Globalization, urbanization and nutritional change in the developing world[END_REF][START_REF] Monteiro | Obesity and inequities in health in the developing world[END_REF][START_REF] Hawkes | Trade, food, diet and health: perspectives and policy options[END_REF]. Nutrition transition moving towards diets of highly processed foods and animal products with high levels of saturated fats is now developing rapidly in middle-and low-income countries, changing the face of food consumption [START_REF] Popkin | The shift in stages of the nutrition transition in the developing world differs from past experiences![END_REF][START_REF] Friel | Unequal Food Systems, Unhealthy Diets[END_REF]. In the meantime, especially in the developed world, a disproportionate consumption of meat, dairy products and processed foods is generating a rapid increase of food-related health problems, such as obesity and diabetes [START_REF] Liverman | Food systems and the global environment: An overview[END_REF].

Recent years have shown that access to cheap food has led to an explosion of obesityrelated problems in developed nations. In fact food prices and food affordability are still main causal factors of food choices, obesity and non-communicable diseases [START_REF] Lee | Monitoring the price and affordability of foods and diets globally[END_REF][START_REF] Brunori | Security for whom? Changing discourses on food in Europe in times of a global food crisis[END_REF]. Food consumption patterns vary with different lifestyles and are characterized by wide gaps in the frequency and in the amounts consumed [START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF]. The often-strong focus of consumers on low-price and convenience products overcome concerns for the risks of obesity or diabetes, generated by overconsumption of these foods [START_REF] Ericksen | The value of a food system approach[END_REF].

Moreover, increases in calorific intake are also associated with shift in eating habits such as a greater intake of sugar and other calorific sweeteners, more frequent consumption of foods away from the home and in fast foods. In fact, the nutritional quality of meals prepared at home can be quite different to that of meals acquired outside (vending machines, restaurants and fast food outlets) [START_REF] Nielsen | Changes in beverage intake between 1977 and 2001[END_REF]. At now, in several countries the majority of persons spend less than 30 minutes per day for food preparation and processed foods constitute the bulk of consumption.

Furthermore, generally, out-of-home food consumption diminishes control over the amounts of calories within-and the nutritional quality of the foods consumed, especially calories provided by fats and sugars. In several major countries and specifically in Mexico, USA, and UK, it has been observed that energy from sugarsweetened beverages and other energetic beverages augmented to 17-25% of total energy intake [START_REF] Popkin | Contemporary nutritional transition: determinants of diet and its impact on body composition[END_REF]. In terms of energy balance, as well as the energy that enters the body, it is also important to consider the amount of energy expended by the consumer. Changes in food consumption patterns also imply the adoption of habits, or the abundance of jobs, leisure and transport options that are mainly sedentary [START_REF] Swinburn | Dissecting obesogenic environments: the development and application of a framework for identifying and prioritizing environmental interventions for obesity[END_REF]. It also must be mentioned that policies and processes of globalization promote excessive consumption of calories [START_REF] Unscn | Fourth Report on the World Nutrition Situation, United Nations System Standing Committee on Nutrition (SCN)[END_REF][START_REF] Garrett | Stunted child-overweight mother pairs: Prevalence and association with economic development and urbanization[END_REF][START_REF] Friel | Unequal Food Systems, Unhealthy Diets[END_REF].

Such dietary changes, characterized by consumption patterns that are increasingly homogenized and based on few global crop commodities and highly processed food products, generate also declines in diversity in human oral and gut microbiota, negatively impacting health and leading to obesity and overweight [START_REF] Lozupone | Diversity, stability and resilience of the human gut microbiota[END_REF][START_REF] Khoury | Increasing homogeneity in global food supplies and the implications for food security[END_REF]. According to WHO data, overweight or obesity concern over two-thirds of women population in North Africa and the Middle East, and the half of women in Latin America and the Caribbean, with an increase of 0,92% per year and 0,31% per year respectively (Popkin, 2013).

Shifting from actual consumption trends have been identified as a response to rising levels of obesity, cholesterol levels, and other diet-related illnesses [START_REF] Burch | The "wellness" phenomenon: Implications for global agri-food systems[END_REF]. This is slowly leading to public awareness campaigns and community movements for more healthy diets [START_REF] Barling | Current trends in food retailing and consumption and key choices facing society[END_REF][START_REF] Obersteiner | Green food systems for 9 billion[END_REF]. Cultural knowledge on preparing varied diets and on nutritional and health benefits of the foods can contrast the negative effects of changing consumption patterns [START_REF] Termote | Eating from the wild: Turumbu indigenous knowledge on noncultivated edible plants, Tshopo District, DRCongo[END_REF][START_REF] Kuhnlein | Indigenous peoples' food systems: the many dimensions of culture, diversity and environment for nutrition and health[END_REF].

As in ecological systems, increasing diversity in gut microbiota may confer further resilience through bacteria likely to have high functional response capacities, hence helping consumers to avoid the effects of a decreased dietary diversity (Lozupone et al., 2012). Therefore, dietary therapeutic strategies to improve gut microbiota, may represent appropriate treatments to counteract overweight and obesity and manage metabolic health [START_REF] Cardoso | The effects of green tea consumption and resistance training on body composition and resting metabolic rate in overweight or obese women[END_REF]Nadal et al., 2008;[START_REF] Lopez-Legarrea | The influence of Mediterranean, carbohydrate and high protein diets on gut microbiota composition in the treatment of obesity and associated inflammatory state[END_REF].

Developing policy to warrant food security is a critical challenge that needs inclusive and integrated analytical approaches [START_REF] Maxwell | Food Policy Old and New[END_REF] and the involvement of the stakeholders is key to building up a framework and to assigning hierarchy to measurements [START_REF] Aubin | A critical panorama of methods used to assess food sustainability[END_REF]. Experimental research and case studies, however, are required to show if this approach (SES and Vulnerability/Resilience) is useful for food system management. There is also a need for outcome-orientated assessment criteria to focus on food security (Ericksen, 2008c). There is a call for system approaches to capture the dynamic processes between and within the food system activities, nutrition and health, and environmental outcomes. Computational complex systems modeling techniques aim at capturing the co-evolution of human and biological systems, and the complexity of human decision-making [START_REF] Hammond | A systems science perspective and transdisciplinary models for food and nutrition security[END_REF]. They allow exploring key processes and outcomes of the analyzed systems for food and nutrition security, delivering innovative and deeper insights at the environmental level. Efforts for strengthening the understanding of the theories of vulnerability and resiliencies within the food systems, through the social-ecological systems frameworks, are needed to explore the sustainability of the food system.

-Insights into a framework to explore the sustainability of the food systems

Research analyses of Food Systems and Food Security through the SES frameworks

As stated above, resilience, vulnerability and adaptability have long been employed within the SES frameworks by different research areas and reflect the emergent properties of a system concerning its ability to respond to a changing environment and are strongly context dependent, especially in spatial and temporal scales and perspectives [START_REF] Carpenter | From metaphor to measurement: resilience of what to what?[END_REF][START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF][START_REF] Callo-Concha | Approaches to managing disturbance and change: Resilience, vulnerability and adaptability[END_REF].

The SES frameworks and the theories of vulnerability and resilience have been suggested and applied, through different approaches, to the study of food systems at regional and subregional level by several international research teams and institutions from a global perspective. Four approaches of differing size and caliber are reported here as examples.

Global Environmental Change and Food Systems-GECAFS

Global Environmental Change and Food Systems (GECAFS) was a ten years long (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011) international and interdisciplinary research comprehensive programme aimed at understanding the relationships between food security and global environmental change. A major objective of GECAFS was to identify strategies to cope with the impact of global environmental change on food systems and to determine the environmental and socio-economic consequences of adaptive feedbacks towards food security, through improving understanding of the interactions between food systems and the Earth System's key socioeconomic and biogeophysical components. The project delivered an innovative conceptual and analytical framework as well as methodological tools to investigate how global environmental change affects food security at a regional scale, strengthening multidisciplinary efforts and engaging development communities in policy discussions to improve food security. The project focused on human activities within the food system and operated on decision support systems to communicate GEC issues to policy-makers in a structured and systematic manner and integrated social and natural science understandings of how food systems are vulnerable to global environmental change (through the concepts of 'vulnerability' and 'adaptation') to better identify feasible adaptation options for food systems (GECAFS, 2011;Ingram et al., 2010) 2nd EU SCAR Foresight Exercise

In the 2nd Foresight Exercise (2008) of the Standing Committee for Agricultural Research (SCAR) of the European Union, it was considered insufficient to simply look just at the multiple dimensions of food security (availability, access and utilization) and it was thus proposed that the analysis be enlarged to the several biophysical and socioeconomic constraints that are determinants of a state of uncertainty of the food system. The foresight report attempts to answer, from a system perspective, the explicit question "how to reduce the vulnerability of social, economic and ecological systems", exploring the risks and opportunities emerging from systemic feedback-loops, and linking the approach of vulnerability to the concepts of ecosystem services and sustainable development. The report identified, described in detail and justified several sets of drivers of change (economic, social, environmental, technological, and policy) at a global and European level. This effort is directed towards a wider resilience perspective beyond the narrow view of food security, changing attitudes to risk, and privileging diversification over specialization [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. opportunities that the food sector will face in the future. The evaluation of the vulnerability and resilience of current and future European food systems is conceived at different levels to pinpoint the directions for European policies that aim to tackle these multiple challenges. Through this systemic and modeling approach, with the involvement of a wide range of stakeholders, and by designing of scenarios for the desired transition pathways in the food system the project aims to understand the sustainability frontiers of different food production systems under the new unfolding conditions and the vulnerabilities of European food systems vis-à-vis future shocks and stresses, and how these may affect FNS focusing on the diversity of local situations within the EU and within regions (TRANSMANGO, 2014).

TRANSMANGO

Metrics of Sustainable Diets and Food Systems

"Metrics of Sustainable Diets and Food Systems" is a multi-institutional small-scale project (Bioversity International & CIHEAM-IAMM, 2014) and its aims consisted of exploring the different approaches to assess the sustainability of diets and food systems, establishing a multidisciplinary taskforce of experts, and identifying a shortlist of indicators for sustainable diets and food systems. The initial focus was in the Mediterranean region at a sub-regional level. The research approach builds on the assumptions that sustainability assessment aims at capturing the ability of a system to maintain and enhance its essential functions over time, and that sustainability addresses threats to preserving life support systems, including their capacity to withstand and adjust. It was considered key to assess stocks of-and changes in human and natural assets. Derived from sustainability sciences, the scientific approach was based on the theories of vulnerability and resilience within the social-ecological systems frameworks, in order to analyze the sustainability of critical food and nutrition security issues. A double set of drivers of change and context-specific food and nutrition security issues were identified at a subregional level. This theoretical modeling exercise allowed the identification of a first suite of indicators. A reduced pool of metrics was then obtained through an expert-based elicitation process (Delphi Survey), moving beyond subjective evaluation and reaching consensus. This smallscale initiative involves a specific and technical selection of indicators (Chapter 5 closely refers to the application and results of this project).

The common thread that links these four different programs (for size and aims) is the approach that is built on the dynamic perspective of the social-ecological systems and the related complex interactions occurring around and inside the food systems. The concepts of vulnerability and resilience are adopted across these projects, even if through different applications and goals with respect to the different understanding of the sustainability of the food systems. Because of the SES scientific approach, the geographical analysis of the food system is carried out at a regional level. The GECAFS project demonstrated how food systems could be conceptualized as coupled social-ecological systems (see Figure 1) and that vulnerability arises in SES from multiple stressors operating across different temporal and spatial scales and levels. In this project and in the 2nd EU SCAR Foresight Exercise it is emphasized the need to identify not only what stresses and changes cause vulnerability, but also the importance of considering the multiple interactions among these stresses and changes.

Building also on this broad theoretical approach, the Metrics of Sustainable Diets and Food Systems' project proposed a specific and reductionist operationalization of the vulnerability and resilience analysis and assessment, strengthening the importance of this analyses for guiding the understanding towards the sustainability of the food systems.

Contribution of the SESs frameworks and Vulnerability & Resilience theories to

Sustainability analyses

Despite the strong orientation of the applications of SESs frameworks and vulnerability and resilience theories towards sustainable development interventions

and exploring the biophysical factors that endanger the sustainability of socialecological wellbeing, the conceptual connectivity and relationship with sustainability is still not obvious. Starting from [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] there has been a strong effort to encourage the consideration of the usefulness of vulnerability and resilience research for sustainability science.

SESs frameworks for Sustainable Development

Various frameworks have been developed aiming at defining a common language, framing research and guidance towards sustainable development of SES [START_REF] Gallopín | Science for the Twenty-First Century: From Social Contract to the Scientific Core[END_REF][START_REF] Holling | Adaptive inference for distinguishing credible from incredible patterns in nature[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Ostrom | A diagnostic approach for going beyond panaceas[END_REF], and the SESs frameworks variables have been key in identifying sustainable outcomes in natural resources management. The variables selected through the SESs frameworks explain the dynamics and the interactions in the social and ecological systems and the framework provides also further variables for exploring the potential sustainable development and management strategies of a social-ecological system [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF]Schluter et al., 2014). This type of framework is suitable for the analysis of complex social-ecological issues that consist dynamic interactions, and for answering research questions about what are the characteristics, activities and dynamic factors of the system leading to, or impeding sustainable management [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF]. [START_REF] Scoones | Dynamic Systems and the Challenge of Sustainability[END_REF] support a new science for sustainability that integrates established perspectives from natural-and social sciences, also through adding "a positivist, sometimes reductionist, analytic" to comprehensive, holistic, multidisciplinary and multi-stakeholders scientific approaches [START_REF] Holling | Two cultures of ecology[END_REF].

Moreover, Schroeter et al. (2005) foster the link between the common goals of sustainability science and global change vulnerability assessment towards the suitability, efficacy, equity, and legitimacy of the outcomes for further sustainable interventions and development pathways [START_REF] Kates | Sustainability Science[END_REF][START_REF] Clark | Sustainability science: the emerging research program[END_REF][START_REF] Yu | Proposing an interdisciplinary and cross-scale framework for global change and food security researches[END_REF]. Indeed, the concepts of resilience and adaptive capacity are often associated with sustainability [START_REF] Conway | Agroecosystem analysis[END_REF][START_REF] Strunz | Is conceptual vagueness an asset? Arguments from philosophy of science applied to the concept of resilience[END_REF]. Resilience, vulnerability and adaptability concepts have been applied in interdisciplinary research and broadly developed as proxies for sustainable strategies [START_REF] Turner | Vulnerability and resilience: coalescing or paralleling approaches for sustainability science?[END_REF], through the hypothesis that a broadly resilient but slightly vulnerable and strongly adaptable system could maintain its functions over time [START_REF] Callo-Concha | Approaches to managing disturbance and change: Resilience, vulnerability and adaptability[END_REF]. [START_REF] Pretty | Agricultural sustainability: concepts, principles and evidence[END_REF] and [START_REF] Schewenius | Opportunities for Increasing Resilience and Sustainability of Urban Social-Ecological Systems: Insights from the URBES and the Cities and Biodiversity Outlook Projects[END_REF] describe how sustainability in agricultural systems integrates the concepts of resilience and persistence (the abilities of a system to buffer disturbance and change and to continue over long periods) while focusing on wider economic, social and environmental outcomes [START_REF] Holling | Resilience and stability of ecological systems[END_REF][START_REF] Folke | How resilient are ecosystems to global environmental change?[END_REF][START_REF] Chelleri | Multidisciplinary Perspectives on Urban Resilience: A Workshop Report, Basque Centre for Climate Change[END_REF][START_REF] Elmqvist | Urbanization, biodiversity and ecosystem services: Challenges and opportunities[END_REF].

Building on the shift of the understanding of sustainability from the formal definition of Sustainable Development (UN, 1987), as threefold focus of the human efforts [START_REF] Martins | Framework for sustainability metrics[END_REF], to a widely established perspective of sustainable systems that are dynamic in response to unexpected events and disturbances [START_REF] Holling | The backloop to sustainability[END_REF], many approaches were identified to systemize the study of change. Thus sustainability can be described as the ability of a system to rebound from shocks and stresses [START_REF] Holling | Investing in research for sustainability[END_REF][START_REF] Ludwig | Sustainability, stability, and resilience[END_REF][START_REF] Folke | Social-ecological resilience and behavioural responses[END_REF][START_REF] Scoones | Dynamic Systems and the Challenge of Sustainability[END_REF]. This latter perspective is key to exploring and anticipating the trends of the changing phenomena occurring, to reducing impact, and to fostering towards the system pathways in the analysis of sustainability [START_REF] Callo-Concha | Approaches to managing disturbance and change: Resilience, vulnerability and adaptability[END_REF]. Sustainability focuses on pressures affecting the perpetuation of life support systems and provides practitioners and decision makers with understanding of these disturbances, their implications, and the ability of the system to cope with them [START_REF] Turner | Vulnerability and resilience: coalescing or paralleling approaches for sustainability science?[END_REF]. To identify sustainable solutions to world agrofood systems, it is considered key to account for and explore the dynamic uncertainty represented by a set of key drivers of change [START_REF] Thompson | Agri-food System Dynamics: pathways to sustainability in an era of uncertainty[END_REF].

Operationalizing Vulnerability & Resilience for a system analysis

Within the SES's analysis, the theories of vulnerability and resilience have proved a useful framework for understanding the dynamic interconnectedness between humans and the environment, and have offered models for improving society's capacity to deal with global change. The main goal of assessing resilience is to pinpoint vulnerabilities in social-ecological systems [START_REF] Berkes | Navigating social-ecological systems: building resilience for complexity and change[END_REF]. Such knowledge is crucial for implementing sustainable management strategies and actions [START_REF] Rammel | Co)evolutionary approaches to sustainable development[END_REF][START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF]. Nevertheless there is still a need for further understanding of the dynamics of sustainability of SESs [START_REF] Carpenter | Resilience: accounting for the noncomputable[END_REF]Schluter et al., 2014) and for a deeper comprehension in social and sustainability science in global change and food security for assessing the food system's vulnerabilities and the socioeconomic and political strategies of adaptation [START_REF] Yu | Proposing an interdisciplinary and cross-scale framework for global change and food security researches[END_REF].

However, resilience and vulnerability are problematic to operationalize through precise assessment methods [START_REF] Cummins | Large scale food retailing as an intervention for diet and health: quasi-experimental evaluation of a natural experiment[END_REF] due to their theoretical and multidimensional nature [START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF]. [START_REF] Scoones | Dynamic Systems and the Challenge of Sustainability[END_REF] underline that system functions have to be sustained in the face of vulnerabilities occurring at different spatial and temporal scales and suggest that there are four necessary but individually insufficient properties that define the sustainability of a system: stability, durability, resilience and robustness. [START_REF] Stave | Dynamic thinking about food system vulnerabilities in highly developed countries: Issues and initial analytic structure[END_REF] proposes, in system dynamics terms, to describe the resilience of a food system, or a simple food system unit, through an analysis of the stocks, building on the hypothesis that any given stock might be sustainable if the flows in and out of the stock are the same. This approach would allow observation of how different conditions of sustainability might have different consequences for the resilience of the system, with respect to its abilities to cope with change through the available socioeconomic, environmental and institutional assets.

In order to structure the vulnerability and resilience analysis of the social-ecological systems towards a more sustainable future, [START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF] consider that it is first necessary to identify the limits of the focal system [START_REF] Carpenter | State of the world's freshwater ecosystems: physical, chemical, and biological changes[END_REF] that can be designed through biophysical factors, political frontiers, and cultural aspects.

In fact each specific system is integrated within other systems across different spatial and temporal tiers. The regional level is considered an important level for food security, food system research and global environmental change considerations. The sub-global, or sub-continental geographical regions scale is a natural level for studies of social-ecological systems (such as food systems) since they are generally defined by common cultural, political, economic and biogeographical contexts. Furthermore, research at regional scale can deliver a set of assets to practitioners, researchers, policy-makers, natural resource managers and other stakeholders for focusing the attention on global change and food security [START_REF] Liverman | Why regions?[END_REF]. Although regions are not always clearly homogenous for socioeconomic and biophysical aspects, before any vulnerability and resilience assessment is necessary to draw artificial boundaries to define a study area (Schroeter et al., 2005). Thus, considering that vulnerability is extremely context-specific, [START_REF] Cordell | Phosphorus vulnerability: a qualitative framework for assessing the vulnerability of national and regional food systems to the multidimensional stressors of phosphorus scarcity[END_REF] and that global change is manifest through sub-global or regional driving forces, cross-scale trade-offs will need to be identified.

When applied to the food system, the system thinking gives us a dominant perspective that allows for global complexity and nonlinearity [START_REF] Ulanowicz | Ecology, the ascendent perspective[END_REF]. A complex system refers to a system constituted from numerous components with numerous types of relationships, and presenting as a whole more characteristics than as a single component individually. Several approaches, analytical frameworks and fields of knowledge originate from these principles, such as systems dynamics, systems of systems, ecological thinking, ecosystem approach, systems thinking, etc. [START_REF] Callo-Concha | Approaches to managing disturbance and change: Resilience, vulnerability and adaptability[END_REF].

Assessing vulnerability to sustainability problems

Starting from the analytical approach of vulnerability and resilience in relationship to global environmental change, but specifically working on phosphorus resource vulnerability, [START_REF] Cordell | Phosphorus vulnerability: a qualitative framework for assessing the vulnerability of national and regional food systems to the multidimensional stressors of phosphorus scarcity[END_REF] define a set of several attributes that are necessary to meet the challenge to assess vulnerability to sustainability problems (problems such as climate change, natural resources depletion, peak oil, market and political instability etc.): integration and inclusiveness of and within coupled humanenvironment systems; record of complexity of interacting stressors and nested scales; participation of relevant stakeholders; assessment over time for current and future vulnerabilities; study of solutions-oriented adaptation and system resilience strategies; policy-relevance.

Several scholars proposed different approaches for measuring resilience, spanning from measuring context-dependent proxies of resilience for each SES [START_REF] Bennett | A systems model approach to determining resilience surrogates for case studies[END_REF][START_REF] Carpenter | Scenarios for ecosystem services: an overview[END_REF] to more quantified approaches such as mathematical models [START_REF] Fletcher | Operationalizing resilience in Australian and New Zealand agroecosystems[END_REF] Despite vulnerability and resilience theories proven key in the investigations of complex social-ecological systems [START_REF] Leach | Re-framing Resilience: a Symposium Report[END_REF], there is still a need for appropriate metrics, in order to measure the conditions of the system and the stages that have been gained towards resilience, that could be achieved through developing a more flexible process of identification of indicators and proxies [START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF].

Moreover, since there is a growing acknowledgment that the impact of food security research on decision making needs to be strengthened, the approach of socialecological systems science is considered as the key to support decision makers in accounting the broad sets of interplaying stressors towards definition of resilience solutions [START_REF] Vermeulen | Addressing uncertainty in adaptation planning for agriculture[END_REF]Vervoort et al., 2014). Hunger problems rely also on the increasing complexity of food systems and an analysis focusing on system dynamics, interactions, feedbacks and non-linear relationship could contribute to identify resilience pathways [START_REF] Ramalingam | Exploring the science of complexity: Ideas and implications for development and humanitarian efforts[END_REF][START_REF] Thompson | Addressing the dynamics of agri-food systems: an emerging agenda for social science research[END_REF][START_REF] Gerber | Food Security as an Outcome of Food Systems[END_REF]. However, vulnerability and resilience theories are not normative concepts [START_REF] Adger | Vulnerability[END_REF], and they therefore need to be used and integrated conjointly with other normative concepts, in order to create a constructive dialogue with policymakers [START_REF] Leach | Re-framing Resilience: a Symposium Report[END_REF][START_REF] Plummer | Social-ecological resilience and environmental education: Synopsis, application, implications[END_REF].

Innovative and appropriate approaches to analysis and assessment should still focus on complexity of food system for their intrinsic entangled and questioned nature [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. For unraveling essential problems in the analysis of socialecological systems, inter and transdisciplinary research is largely deemed as extremely helpful [START_REF] Carpenter | Resilience: accounting for the noncomputable[END_REF]Hammond & Dube´, 2012;[START_REF] Ostrom | A General Framework for Analyzing Sustainability of Social-Ecological Systems[END_REF]MEA, 2005[START_REF] Liu | Complexity of coupled human and natural systems[END_REF][START_REF] Huber | Sustainable land use in mountain regions under global change: synthesis across scales and disciplines[END_REF], especially in terms of assessment of wide sets of potential outcomes, agreement within multiple stakeholders with different goals and intervention pathways, and modeling complex dynamics across the different tiers of food systems. Various qualitative and quantitative methodologies can be implemented and integrated in hybrid frameworks using data and information on previous experiences, in order to seize system complexity and identify synergies and trade-offs for decision-making [START_REF] Ericksen | Food security and global environmental change: emerging challenges[END_REF][START_REF] Anderies | Robustness of Social-Ecological Systems: Implications for Public Policy[END_REF][START_REF] Saldarriaga | Dynamic decision making in coupled social-ecological systems[END_REF].

Despite valuable and numerous efforts, most applications of the social-ecological systems frameworks still belong to the scientific community, whilst development practitioners' interest for this framework might be inhibited by its system-orientation and problems with agency that may not be adequately developed or studied [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. Frameworks, theories, and models are the elementary units that the scientific community applies to developing, proving and adjusting knowledge, and, through an integrative approach, they are fundamental for creating common languages, answering questions about mechanisms of a system at various scales and under changing states [START_REF] Epstein | Missing ecology: integrating ecological perspectives with the social-ecological system framework[END_REF]. However, such more integrative and holistic science, and within an interdisciplinary context, may provide reductionist analytic approaches that can be refined through dialogue and interaction across disciplines, sectors, policy debates and coordination [START_REF] Holling | Two cultures of ecology[END_REF]Scoones, 2007).

Although dynamic models are strongly proposed as suitable tools to explore socialecological interactions, it still remains extremely challenging because of the complexity of the systems studied and the integration and development of knowledge, theories, and approaches from different disciplines (Schluter et al., 2014). Attempts of integration of different frameworks for analyzing social and ecological systems have been proposed. For example by [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF] who attempt to integrate the vulnerability framework into the application of the SES frameworks for the food system, and also alternatively by [START_REF] Loring | The new environmental security: linking food, water and energy for integrative and diagnostic social-ecological research[END_REF] who propose to integrate the Water-Food-Energy nexus into a diagnostic application of the SES frameworks.

Measuring sustainability and transferring scientific information to policy-makers

Assessing issues related to sustainability problems, with the goal of informing the decision-making process and policy-makers, involves a number of critical implications. There is, in fact, a growing debate about the importance of the role, utility, adoption, focus and final goals of the sustainability indicators.

Indicators and composite indices are often considered key to presenting complex data and trends to policy makers through scientific evidence. For their capacity to synthetize multifaceted issues they are deemed as important tools to simplify complex datasets to be communicated and used by non-specialists that need to advocate their policy and management activities with evidence [START_REF] Bell | Measuring Sustainability Learning from Doing[END_REF], 2008;[START_REF] Hezri | Sustainability indicators, policy and governance: issues for ecological economics[END_REF][START_REF] Dale | Challenges in the development and use of ecological indicators[END_REF]. Furthermore, since the contemporary historical and political context allowed raising a plethora of initiatives focused on the identification and formulation of indicator to assess society's wellbeing and development, there is also an increasing public and expert-based debate, at different stakeholder levels, on the issues related to the identification and use of indicators of sustainability [START_REF] Stiglitz | Report by the commission on the measurement of economic performance and social progress[END_REF][START_REF] Sébastien | Use and influence of composite indicators for sustainable development at the EU-level[END_REF]. In the meantime the identification of indicators for the policy use and the pathway leading to the choice of indicators, often through group dynamics, are challenged to be traceable and evidence-based for guaranteeing transparency in decision-making and effectiveness of evidence-based policy (Bell & Morse, 2013).

However, the integration level and the role of the policy indicators, in the institutional decision making processes, are uncertain and questioned by several scholars who demonstrate that the contemporary idea based on the existence of direct and transparent links between the formulation of evidence-based indicators and the use made by policy-makers is highly arguable and can be considered rather dogmatic [START_REF] Innes | Information in communicative planning[END_REF][START_REF] Ayres | Commentary on the utility of the ecological footprint concept[END_REF][START_REF] Gudmundsson | The policy use of environmental indicators-learning from evaluation research[END_REF][START_REF] Lehtonen | The environmental-social interface of sustainable development: capabilities, social capital, institutions[END_REF][START_REF] Hezri | Sustainability indicators, policy and governance: issues for ecological economics[END_REF][START_REF] Rosenström | Exploring the policy use of sustainable development indicators: interviews with Finnish politicians[END_REF][START_REF] Boulanger | Political uses of social indicators: overview and application to sustainable development indicators[END_REF][START_REF] Rydin | Re-examining the role of knowledge within planning theory[END_REF][START_REF] Turnhout | Ecological indicators: between the two fires of science and policy[END_REF][START_REF] Bell | Sustainability indicators: measuring the immeasurable?[END_REF][START_REF] Bell | An analysis of the factors influencing the use of indicators in the European Union[END_REF][START_REF] Bauler | An analytical framework to discuss the usability of (environmental) indicators for policy[END_REF][START_REF] Sébastien | Use and influence of composite indicators for sustainable development at the EU-level[END_REF]. In fact policy decisions are not only based on the quality of the information provided but also on other factors linked to the argument and the power of individuals, or groups of people, who are making policies, and also to their interests, intentions and to the surrounding institutional and evolving social contexts.

Often we measure what we want to measure. In fact, some key and acknowledged indicators can provide information only on the aspects for which they have been created to measure (Bell & Morse, 2013). Also, there are several and different ways to interpret indicators and select data. It is, therefore, important to know how the information about the indicators is transferred to policy-makers, and which are the actual aims of using the indicators [START_REF] Chess | Communicating about environmental indicators[END_REF]. For instance, indicators might also be used for justifying decisions that would have been taken anyhow, or, in other cases, the lack of indicators could be used to justify the inertia in policy-making [START_REF] Gudmundsson | The policy use of environmental indicators-learning from evaluation research[END_REF][START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF]. The role of press, as intermediary on the communication of information through indicators, is also crucial [START_REF] Bell | An analysis of the factors influencing the use of indicators in the European Union[END_REF], and aggregation of data also can strongly alter the messages for policy-makers [START_REF] Chess | Communicating about environmental indicators[END_REF].

Several studies demonstrated also that often the indicators that have been prepared in appropriate technical manner are not actually applied nor they have a real impact on policy-making (Bell & Morse, 2013). A study of [START_REF] Sébastien | Use and influence of composite indicators for sustainable development at the EU-level[END_REF] tries to answer questions about the necessity to increase the understanding of the motivation that pushes policymakers, stakeholders, civil society and citizens to adopt indicators and composite metrics, and how those measures actually impact policies in complex society dynamics. In that study [START_REF] Sébastien | Use and influence of composite indicators for sustainable development at the EU-level[END_REF] Referring to EU institutions, the authors [START_REF] Sébastien | Use and influence of composite indicators for sustainable development at the EU-level[END_REF]) used these findings to prove the need of a greater involvement of the actors in the political and institutional contexts where indicators have to be identified and applied. These elements are confirmed also by similar results that were found in other works that show that research involving sustainability indicator use and effect needs to take into account the geographical, socioeconomic and cultural context within which such tools are implemented, and not only to be a technical exercise [START_REF] Cassar | Assessing the use and influence of sustainability indicators at the European periphery[END_REF].

Specifically, with regards to vulnerability assessment, [START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF] warns from many common usages of vulnerability indicators, rising important questions both for science and policy-making. The arguments of the author are related to vulnerability to climate change, but they can be of great help if they are applied and interpreted for a vulnerability and resilience approach to study the sustainability problem of the food system. Vulnerability assessments' main goal is to inform decision-making (Schroeter et al., 2005;[START_REF] Patt | An introduction to the diversity of approaches to vulnerability research and assessment: common features and lessons learned[END_REF]. In particular, for [START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF] As mentioned above, communication and intermediaries, such as the press, play a key role in transferring information through the use of indicators. The concept of vulnerability is complex and difficult to be used for risk communication.

In particular the author [START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF] identifies in the different scales and levels of analysis some of the main parameters and technical issues to consider for judging the validity of using vulnerability indicators. Also the research on vulnerability assessment and indicators does not imply a specific research question and may generate confusion. A more specific contextualization of the research goals and tools might avoid this confusion and lack of research question, describing the system problems, defining particular factors of vulnerability, identifying vulnerable units of systems, and then applying the use of variables.

-Conclusions

Food and nutrition security, as principal outcome of the food system, needs to be sustained over time. A deeper understanding of the interrelated dynamics of change that govern the complexity of the food systems is necessary to identify the threats to the sustainability of the food systems. Scholars and policy-makers call for metrics of food security and sustainability of the food system, in order to provide decisionmaking with appropriate information [START_REF] Barrett | Measuring Food Insecurity[END_REF][START_REF] Dicks | What do we need to know to enhance the environmental sustainability of agricultural production? A prioritisation of knowledge needs for the UK food system[END_REF].

Considering food systems as complex social-ecological systems and thus analyzing together natural and social systems and their interactions as one system with critical feedbacks throughout temporal and spatial scales, interdisciplinary and integrated investigation approaches become key for exploring and designing effective responses to human-environment interactions related to food and agriculture in a unpredictable and dynamic context [START_REF] Ericksen | Assessing the Vulnerability of Food Systems to Global Environmental Change: A Conceptual and Methodological Review[END_REF][START_REF] Thompson | Agri-food System Dynamics: pathways to sustainability in an era of uncertainty[END_REF]. Several studies identify vulnerability and resilience for helping draw causal dynamic interactions affecting the sustainability within the food systems. Building on a SES framework for the food system, vulnerability and resilience theories operationalize a causal pathway to identify which are the variables concerned with the sustainability of the food system outcomes. A set of indicators of exposure, sensitivity and resilience could proxy the variables that describe the sustainability interrelations underneath the sustainability of the food systems and could be selected through an interdisciplinary and reproducible method. However, first it is necessary to shape a methodological and organized structure, identify the driving forces to which the food system might be vulnerable, and categorize the food system units that are likely to be exposed. In fact the primary goal of assessing resilience is to identify vulnerabilities in socialecological systems to create a more sustainable future for people [START_REF] Berkes | Navigating social-ecological systems: building resilience for complexity and change[END_REF][START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF].

However, while vulnerability and resilience theories are helpful as metaphors, in metrics they are still considerably weak tools for assessment [START_REF] Carpenter | From metaphor to measurement: resilience of what to what?[END_REF][START_REF] Cabell | An indicator framework for assessing agroecosystem resilience[END_REF]. According to [START_REF] Cummins | Large scale food retailing as an intervention for diet and health: quasi-experimental evaluation of a natural experiment[END_REF], resilience and vulnerability are problematic to operationalize for their abstract and multi-dimensional nature. Furthermore, since it is system-oriented, the social-ecological systems frameworks approach is still a research tool exclusive of the scientific community and not yet suitable for development practitioners because of limited options for agency [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. Also integration of different theories, models and frameworks originating from various disciplines might lead to analytical reductionism in the study of complex and interrelated food systems (Scoones, 2007) and further problems might derive from the multiple temporal scales and spatial levels that need to be considered within a complex food system.

Taking into account these factors highlights the challenges that the assessment of vulnerability and resilience faces within the study of the sustainability of the food system in order to satisfy the consideration of a set of aspects such as the coupled human-environment systems, complex interactions and driving forces, nested spatial scales, involvement of stakeholders through participatory process, dynamic assessment over time, providing information for decision-and policy-makings towards resilience.

In the context of a social-ecological system and vulnerability/resilience analysis of the sustainability problems affecting contemporary food systems, these efforts should be directed towards the rising call for system approaches in order to capture the dynamic processes between and within the food system activities, nutrition and health, and environmental outcomes [START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF] and for developing metrics and measurement mechanisms for the sustainability of the food systems to give policymakers information and trade-offs data for intervention and dialogue with the stakeholders [START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF].

There remain no global common metrics to assess the sustainability of a food system [START_REF] Vinceti | The contribution of forests and trees to sustainable diets[END_REF]. A consistent range of evidence-based sustainability metrics and standards needs to be identified to conduct analyses of the quantitative linkages between food security, nutrition, diets, health, agricultural productivity, resource use, environmental impacts, and costs and benefits [START_REF] Beddington | The role for scientists in tackling food insecurity and climate change[END_REF] through joint multidisciplinary efforts of professionals coming from nutrition, agronomy, public health, education, policy-and decision-making and the food sector [START_REF] Tilman | Global diets link environmental sustainability and human health[END_REF].

Indicators direct us to knowledge, and metrics related to the systems' sustainability allow presenting important conditions, complex data, and trends to policy makers (Bell & Morse, 2010;2011). There is, therefore, a need for integrated sets of metrics, understanding different trends and interactions of food systems within the large framework of social-ecological systems, in order to provide practitioners with adequately substantiated modeling tools that allow the results of management decisions to be visualized easily.

-Aims of the thesis

This thesis builds on the social-ecological systems (SES) frameworks and the vulnerability and resilience theories for identifying an assessment tool that expresses the causal dynamics in the interactions (or interplays) between global change drivers and food security outcomes, to guide towards the selection of appropriate metrics.

In the introductory chapter a wide literature review is presented in order to describe the interest of the social-ecological system frameworks -for answering questions about the sustainability problems that affect the functions of the food system -and the previous and future opportunities provided by a vulnerability and resilience analysis.

The second chapter describes food systems as complex social-ecological systems, involving multiple interactions between human and natural components. A strong focus is on nutritional patterns and environment structure that are interconnected in mutual dynamics of change. The systemic nature of these interactions calls for multidimensional approaches, integrated assessments, and simulation tools to guide change. In this chapter conceptual modeling frameworks are described articulating the synergies and tradeoffs between dietary diversity and agricultural biodiversity, and associated ecosystem functions that are crucial resilience factors to climate and global changes.

In the third chapter the fundamental sustainability properties of the social-ecological framework are identified, describing how the vulnerability and resilience theories contribute to the understanding of the causal dynamic interactions of the socioeconomic and biophysical factors acting in the food system. Elements found in literature are reported for illustrating how the vulnerability and resilience approaches are applied for shaping causal interactions building on potential impact and recovery potential.

In the forth chapter it is illustrated the formalization of the food system as a dynamic system. Building on the concepts of vulnerability and resilience the dynamic variables of the food system are identified and modeled following a stepwise application for vulnerability and resilience assessments allowing define the study area, developing context-specific knowledge of the social-ecological system (identifying specific drivers of change), hypothesizing stresses and interactions with the vulnerable issues of the food systems, and finally formalizing these interactions into eight causal models (of vulnerability/resilience). Then we discuss this modeling approach within the context of the assessment of sustainable food systems, and draw further perspectives of research for identifying specific indicators through a vulnerability/resilience modeling exercise.

The last chapter of the thesis illustrates the process of selection of metrics through an expert elicitation method (Delphi survey) that guide to the identification of a reduced pool of indicators, through a shared consensus, selected within a number of dynamic interactions between socioeconomic and biophysical changes, affecting the food system, and food and nutrition security issues, likely to be affected by those changes.

The general aim of this thesis is to analyze and explore the sustainability of the food system through identifying a systemic set of metrics at the Mediterranean level. This general aim involved three specific goals:

Developing a multidimensional framework to improve the dynamic understanding of the sustainability of food systems and diets, applicable to countries of the Mediterranean region.

Identifying the main variables to formalize and operationalize the abstract and multidimensional concepts of sustainable food systems.

Defining metrics for assessing the sustainability of food systems and diets, at a subregional level, combining a vulnerability and resilience framework with a Delphi elicitation process.

Preface to Chapter 2

The stark observation of the co-existence of undernourishment, nutrient deficiencies and overweight and obesity, the triple burden of malnutrition (Pinstrup- [START_REF] Pinstrup-Andersen | Agricultural research and policy to achieve nutrition goals[END_REF], is inviting us to reconsider health and nutrition as the primary goal and final endpoint of food systems. Agriculture and the food industry have made remarkable advances in the past decades.

-Introduction

Humanity faces a global nutrition crisis, with the dual problem of hunger and obesity.

A total of 842 million people still suffer from undernourishment (FAO, 2013a) while obesity has become a significant public health issue with 500 million obese adults [START_REF] Finucane | National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9•1 million participants[END_REF]. More than 1 billion adults are projected to be obese by 2030 if no major effort is made (Kelly et al., 2008). Meanwhile, climate change and environmental degradation are massive threats to human development. Indisputable and unprecedented changes in extreme weather and climate events have been observed and will increasingly have detrimental impacts on livelihoods, particularly in combination with other environmental threats [START_REF] Ipcc | Summary for Policymakers[END_REF]. Above all, global biodiversity is constantly declining, with substantial ongoing losses of populations, species and habitats.

Vertebrate populations have declined by 30% on average since 1970, and up to twothirds of species in some taxa are now threatened with extinction (UNEP, 2012).

These global changes have major implications for food and nutrition security.

There is a bi-directional relationship between the environment and food. Human subjects depend on the goods and services provided by natural and managed ecosystems to meet their food needs. The production of food and its nutrient content are inextricably linked to the environment. Ecological interdependences are key factors for the dietary content of most living species we consume [START_REF] Frison | Agricultural biodiversity is essential for a sustainable improvement in food and nutrition security[END_REF].

The observed environmental degradation and biodiversity depletion, in particular, are affecting the food systems, with implications for yield, quality and affordability (MEA, 2005). At the same time, processes along the food chain, from agricultural production to food consumption, produce other outputs than food that are returned to the natural environment, such as pollution or waste. Human activities impact the diversity of organisms found in ecosystems, and thus influence the provision of ecosystem services.

The links between environmental degradation and food system activities are increasingly recognized and translate into joint negative environmental and nutritional outcomes [START_REF] Ericksen | Food security and global environmental change: emerging challenges[END_REF][START_REF] Gregory | Climate change and food security[END_REF]. The sustainable diets' research and policy agenda essentially aim at putting nutrition and health at the core of sustainable development. However, there is not a clear understanding of the interactions between food systems; their production activities and subsequent outputs, ecological processes and human nutrition. This has resulted in a perceived lack of evidence of the benefits of agrobiodiversity on nutritional outcomes from food systems, preventing agrobiodiversity from being a key consideration in food and nutrition policies.

Since the processes underlying nutrition insecurity and diet-related environmental, economic and social unsustainability derive from a shared food system, a recurrent fundamental question is: what types of system shift could create an enabling environment for sustainable diets? Research has a critical role in answering this type of question. System dynamics are widely considered of particular interest to food and nutrition security (Hammond & Dube, 2012). Starting from a conception of food systems as social-ecological systems, thus fully tackling the systemic dimension of the food sustainability question, this chapter proposes a review and a conceptual modeling framework that articulates biophysical processes with socio-economic dynamics. Within this coupled human-environment framework, taking into account the determinants that influence food consumer behaviors will be key to improving strategies that mitigate negative patterns on health and the environment. It will help frame the agricultural biodiversity's role in nutrition and develop modeling tools for the policy-makers to guide changes towards sustainable diets and food systems.

-Sustainable diets: a new concept calling for changes

A nutrition-driven perspective [START_REF] Gussow | Dietary guidelines for sustainability[END_REF] were the first to suggest the term 'sustainable diet' to describe a diet 'composed of foods chosen for their contribution not only to health but also to the sustainability (the capability of maintenance into the foreseeable future) of the (. . .) agricultural system' [START_REF] Herrin | Designing a sustainable regional diet[END_REF]. Literally, the concept of diet in nutrition refers to the sum of foods consumed by a person.

Whole diet, or dietary pattern, analysis has emerged as an alternative and complementary approach to the study of individual nutrients or foods, highlighting the dynamic and multiple factors involved in eating practices (HU, 2002). It helped better communicate healthy eating messages that emphasize a balance of food and beverages within energy needs (Freeland-Graves & Nitzke, 2013). More fundamentally, adopting a whole-diet approach is now seen as necessary to examine the relationships between nutrition and health. It reflects the increasing recognition of the multidimensional nature of diets and diet-related diseases, from nutrient intakes and metabolism to food consumption behaviors and attitudes [START_REF] Kant | Patterns of recommended dietary behaviors predict subsequent risk of mortality in a large cohort of men and women in the United States[END_REF].

Multidimensionality is further enhanced as the impacts of diets not only on health, but also on the environment or the economy, are considered to assess the sustainability of food choices. The sustainable diet concept advocates for a more consumer-driven thinking on the sustainability of agriculture, promoting a research and policy agenda that introduce nutrition as one of its core dimensions. It claims that understanding the determinants of consumer choices can improve agricultural and food systems, the environment and the health. More fundamentally, it emphasizes the health and food security purpose of food systems, and highlights the need for quality, not just quantity or access.

Advocates promote economically, socially and environmentally sustainable food systems that concurrently ensure 'physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life' (UN, 1996). This reminds us that food, or more precisely feeding people, is agriculture and food systems' main reason for being [START_REF] Haddad | How should nutrition be positioned in the post-2015 agenda?[END_REF]. As such, the concept of sustainable diets provides a food and nutrition security-orientated perspective on the question of the sustainability of food systems. The global climate and other life-supporting environmental systems are seriously perturbed and depleted (IPCC, 2013). These changes include higher temperatures, drought-prone and long-term drying conditions in some sub-tropical regions, rising sea levels, acidification of oceans, declining water quality, depleting fish stocks, increasing frequency and severity of floods and other climate-related natural disasters.

Food security and sustainable development

Biodiversity is also at risk, with 20930 species and ecological communities known to be threatened (IUCN, 2013). Biodiversity, the basis of ecosystem health and future food security, has been more seriously harmed by human activities in the past 50 years than at any other time in human history (UNEP, 2012).

Agriculture and the food sector have historically been major contributors to environmental degradation. For instance, irrigated agriculture globally accounts for 70% of the consumption of freshwater resources (OECD, 2013). However, there is a bi-directional relationship between environmental degradation and food system activities. People, particularly those living in developing countries, are vulnerable to environmental changes that result in reduced quantity, quality and affordability of food. Similarly, nutrition transition and food system transformation go together. The current global health crisis of malnutrition, both in developed and developing countries, and the contemporaneous urging environmental degradation present new challenges for food systems and calls for changes. Improved food systems could be a major partner in the environmental solution.

Diets as system outputs

A crucial question is then: can optimal diets be derived that concurrently meet dietary requirements while reducing detrimental environmental impacts? Contrary to conventional wisdom, recent evidence suggests that high nutritional quality products might not be necessarily more environment-friendly. Although plant-based foods have lower greenhouse gas emissions (GHGE) per unit weight, better quality diets were found associated with significantly higher GHGE after adjustment for energy intake [START_REF] Vieux | Greenhouse gas emissions of self-selected individual diets in France: Changing the diet structure or consuming less?[END_REF][START_REF] Vieux | High nutritional quality is not associated with low greenhouse gas emissions in self-selected diets of French adults[END_REF]. So, can consumers lower, for example, their carbon footprint through making changes in the kind of food they buy, and still meet nutritional adequacy recommendations? MacDiarmid et al. [START_REF] Macdiarmid | Sustainable diets for the future: can we contribute to reducing greenhouse gas emissions by eating a healthy diet?[END_REF] derived what would look like such an optimal diet for a representative UK consumer for different GHGE reduction targets.

Using mathematical linear programming, they conclude that such a diet can be achieved for the GHGE objectives set for 2020 (-25 %); however, meeting the targets for 2050 (-70 %) and dietary recommendations will require a 'radical shift in food consumed'. Ad hoc constraints were added to the model to maintain simulated diets within consumers' acceptability limits. These results clearly show that demand-side approaches to the problem of environmental unsustainability are desirable and likely to contribute to improvements. However, as highlighted by [START_REF] Macdiarmid | Sustainable diets for the future: can we contribute to reducing greenhouse gas emissions by eating a healthy diet?[END_REF], GHGE reductions should be made to both the demand and supply sides within the food chain, in particular to attain longer-term objectives. If other environmental, economic, social and ethical aspects of sustainability were to be included in the optimization model, while strengthening the acceptability constraints, one can wonder if feasible solutions can be derived by changes at the sole food basket level. Linear optimization theory tells us that if there are x decision variables, then a set of x equality constraints needs to be specified for one unique optimal solution and vice versa. Any extra equality constraints will overspecify the problem. If feasible solutions are to be identified, extra decision variables need to be considered. In other words, other levers need to be operated jointly with actions encouraging behaviour changes.

The processes underlying food insecurity and diet-related environmental, economic and social unsustainability derive from a shared food system. For instance, GHGE are not food attributes, but outputs of different activities along the value chain. Food consumption is a heavy contributor to 'embodied' or indirect emissions in products that result from activities prior to purchase (Kim and Neff, 2009). In practice, these indirect emissions are very hard to be accurately estimated and attributed to a good or an individual.

Modeling exercises of optimal diets have had to use so far averages coming from lifecycle assessment studies on, sometimes, rather aggregated food groups. There might thus be a high degree of variation around these average estimates. For instance, Lindenthal et al. ( 2010) report substantial differences in terms of GHGE between organic production methods as compared with conventional farming in Austria (10-21% lower CO2-eq/kg product for organic dairy, 25% for organic wheat bread and 10-35% for organic vegetable.). Similar studies elsewhere have reported the same results (Kustermann et al., 2008;[START_REF] Petersen | Nitrous oxide emissions from organic and conventional crop rotations in five European countries[END_REF].

Consumers stand at the top of the food system and diets are outputs of longer and more complex food chains encompassing several activities. Technologies and policies affect the overall environmental performances, food security and health outcomes [START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF]. To derive optimal sustainable diets, we need to look at all the variables that influence the flow of activities along the food system. These are the levers to act upon. To assess and enhance food sustainability, focus needs to move beyond the food basket while ultimately bearing in mind that diets and nutrition are the final reason for being of the food system. [START_REF] Burchi | The role of food and nutrition system approaches in tackling hidden hunger[END_REF] define a system as 'a set of elements that function together as collective units which have properties greater than the sum of their component parts'. The food system concept describes the required inputs, processes and generated outputs involved in the provision of food and nutrients for sustenance and health, including growing, harvesting, processing, packaging, transporting, marketing, consuming and disposing of food [START_REF] Ericksen | Food security and global environmental change: emerging challenges[END_REF]Ratoin and Ghersi, 2010;[START_REF] Rutten | Food Systems and Food Security: A Conceptual Model for Identifying Food System Deficiencies[END_REF]. The current joint crisis of malnutrition and unsustainability has roots in agricultural and food systems that do not deliver enough essential nutrients to meet dietary requirements for all (Graham et al., 2007;[START_REF] Declerck | Ecological approaches to human nutrition[END_REF]. The solution to sustainable diets lies both in sustainability-orientated food choices and in changes in the food systems. And modern societies depend on complex social-ecological systems to provide food [START_REF] Ericksen | Food security and global environmental change: emerging challenges[END_REF][START_REF] Fraser | A framework for assessing the vulnerability of food systems to future shocks[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Ostrom | A General Framework for Analyzing Sustainability of Social-Ecological Systems[END_REF].

-A complex human-environment system

Food and nutrition as ecosystem services

Agriculture and the food sector at large have a first-hand touchpoint with nature: crops need soil, water, insects for pollination, etc. The analysis of the relationships between resource acquisition and living organisms, at the heart of the sustainable diet concept in the case of human organisms, is also an ecological question, and can surely benefit from insights from ecology. Ecosystems consist of a community of species, or biodiversity, interacting with each other and with their environment. The product of these interactions, which include competition, predation, reproduction and cooperation, is essential to human wellbeing. Human subjects depend on goods provided by natural and managed ecosystems. These goods and other benefits provided by ecosystems to mankind are collectively referred to as ecosystem services (Ecosystem services were defined in the Millennium Ecosystem Assessment (2005) as 'the benefits people obtain from ecosystems', both natural and managed. These services may be categorized as provisional (fiber, food, water and fuel), regulative (climate and disease regulation, water purification), cultural (aesthetics, heritage, education, recreation and spiritual) or supporting services (nutrient cycling, primary production and soil formation)). All are processes through which ecosystem sustain human livelihoods. Food production is an ecosystem service central to human welfare [START_REF] Costanza | The value of the world's ecosystem services and natural capital[END_REF]. The capacity of ecosystems to provide us with the energy and nutrition for our daily life fully depends on the foods that agriculture and food systems provide us. Clear from this process-based interpretation, human nutrition should be considered one of the most fundamental ecosystem services, or alternatively as dependent on several ecosystem services, including provisioning, regulating, supporting and cultural services [START_REF] Declerck | The role of ecological theory and practice in poverty alleviation and environmental conservation[END_REF].

Agricultural biodiversity, or agrobiodiversity, is the sub-component of biodiversity that refers to the biological variety and variability of living organisms that are involved in food and agriculture. It can be considered at three main levels: ecosystem diversity, species diversity and genetic diversity [START_REF] Heywood | Overview of agricultural biodiversity and its contribution to nutrition and health[END_REF]UN, 1992). It includes habitats and species outside of farming systems that benefit agriculture and enhance ecosystem functions such as pollination, soil dynamics and control of GHGE.

Agrobiodiversity comprises the constituents of biological diversity important to food and agriculture as well as for the agroecosystem [START_REF] Frison | Agricultural biodiversity is essential for a sustainable improvement in food and nutrition security[END_REF][START_REF] Brussaard | Reconciling biodiversity conservation and food security: scientific challenges for a new agriculture[END_REF]. Furthermore, it is the result of the deliberate interaction between human subjects and natural ecosystems. Subsequent agroecosystems are thus the product of not just physical elements of the environment and biological resources, but vary according to cultural and management systems [START_REF] Heywood | Overview of agricultural biodiversity and its contribution to nutrition and health[END_REF].

Agrobiodiversity includes a series of social, cultural and ethical variables.

Reduction in agrobiodiversity and simplification of diets

Modern agriculture and food systems are contributing to the simplification of the structure of the environment, replacing nature's biodiversity with a small number of domesticated plant species and animal breeds [START_REF] Altieri | Multifunctional dimensions of ecologically-based agriculture in Latin America[END_REF]. This process has been one of the main factors that allowed much of the human population to enjoy unprecedented levels of development and improved health. However, as efforts have been directed at maximizing production and productivity, uniformity has replaced diversity within cultivated systems [START_REF] Sage | The interconnected challenges for food security from a food regimes perspective: Energy, climate and malconsumption[END_REF]. Agricultural intensification, which implies specialization and genetic standardization, reduction of utilized species, conversion of forests and wild land to anthropogenic habitats, homogenization of soils through amendments, is certainly the first human related cause of biodiversity loss [START_REF] Frison | Agricultural biodiversity is essential for a sustainable improvement in food and nutrition security[END_REF][START_REF] Rosen | European development and environmental risk: Sustainable growth at what cost?[END_REF][START_REF] Tilman | Agricultural sustainability and intensive production practices[END_REF]. The increase in food supply has thus come with important trade-offs that include soil degradation and loss of many regulatory and supporting ecosystem services. These trade-offs can impair the ability of the ecosystems to deliver the essential nutrients for human diets [START_REF] Palm | Soils: a contemporary perspective[END_REF].

This increased reliance on domesticated species and selected crop varieties can be linked to a significant reduction in dietary diversity. Modern agriculture is genetically dependent on a handful of varieties for its major crops [START_REF] Kahane | Agrobiodiversity for food security, health and income[END_REF]. The world's agricultural landscapes are planted mostly with some twelve species of grain crops, twenty three vegetable crop species and about thirty-five fruit and nut crop species [START_REF] Fowler | The threatened gene: food, politics, and the loss of genetic diversity[END_REF]) (as a comparison, one single hectare of tropical rain forest contains on average over 100 species of trees [START_REF] Perry | Forest Ecosystems[END_REF]; cited in [START_REF] Altieri | The ecological role of biodiversity in agroecosystems[END_REF]. This process of simplification of agriculture generated a model where only a small number of crop species dominate our energy and nutritional intakes.

Three crops alone (rice, wheat and maize) account for more than 55% of human energy intake [START_REF] Stamp | Competitive underutilized crops will depend on the state funding of breeding programmes: An opinion on the example of Europe[END_REF].

Although varying in nutrient content, no single crop species is capable of providing all essential nutrients. Nutritional diversity is now widely recognized to be a key factor for adequate diets likely to satisfy the complex human nutritional needs [START_REF] Arimond | Simple food group diversity indicators predict micronutrient adequacy of women's diets in 5 diverse, resource-poor settings[END_REF][START_REF] Roche | Traditional food diversity predicts dietary quality for the Awajun in the Peruvian Amazon[END_REF][START_REF] Randall | Diet diversity and nutrient intake[END_REF][START_REF] Torheim | Nutrient adequacy and dietary diversity in rural Mali: association and determinants[END_REF].

Evidence of the valuable outcomes of diversity in decreasing malnutrition, morbidity and mortality [START_REF] Frison | Agricultural biodiversity is essential for a sustainable improvement in food and nutrition security[END_REF][START_REF] Tucker | Eat a variety of healthful foods: old advice with new support[END_REF] is completed by indications of positive correlation with child growth and survival [START_REF] Arimond | Dietary diversity is associated with child nutritional status: evidence from 11 demographic and health surveys[END_REF][START_REF] Pelletier | Changes in child survival are strongly associated with changes in malnutrition in developing countries[END_REF].

The importance of nutrient diversity for human wellbeing calls for dietary diversification. However, the quality of nutritional supply and human health is in danger because of a loss in biodiversity. A reduction in the consumption of varied, 'nutritionally-rich' and 'functionally-healthy' plant-based foods is reported in most developed and emerging countries (Johns & Eyzaguirre, 2006). The preeminent simplification of human diets, associated with changing lifestyles, led to nutrient deficiencies and excess energy consumption. However, the elimination of most essential nutrient deficiencies (most important micronutrients usually reported are vitamin A, iodine and iron, zinc; Graham et al. ( 2007) provide a list of fifty-one essential nutrients for sustaining human life) requires only small increases in the variety of food items an individual consumes [START_REF] Ruel | Is dietary diversity an indicator of food security or dietary quality? A review of measurement issues and research needs[END_REF]. As a result, balanced nutrition in human diet can depend significantly on the diversity within crops (Mouillet et al., 2010).

Ecological interdependences are key factors of the dietary content of most living species. Some lesser-known cultivars and wild varieties have been reported to be micronutrient superior over other more extensively utilized cultivars. For example, recent analyses have shown that provitamin-A carotenoid content of bananas differs by a factor of 8500 between different cultivars [START_REF] Burlingame | Food composition is fundamental to the cross-cutting initiative on biodiversity for food and nutrition[END_REF]. In Micronesia, the local 'karat' banana has been found to contain high levels of provitamin-A carotenoids, which contribute to protection against vitamin A deficiency and chronic diseases, including certain cancers, heart disease and diabetes [START_REF] Engelberger | Micronesian banana, taro, and other foods: newly recognized sources of provitamin A and other carotenoids[END_REF] (cited in [START_REF] Sajise | Biodiversity research for sustainable development: can it be achieved?[END_REF]. In this regard, the term 'neglected and underutilized species' or 'development opportunity crop' refers to those species whose potential to improve people's livelihood is not being fully exploited (given the current lack of detailed and comprehensive nutritional information about diversity within crops at the cultivar level and the role it plays in nutrition, the Food and Agriculture Organization has launched the INFOODS initiative (Mouillet et al., 2010;Padulosi et al., 2011). For instance, a local fruit, Berchemia discolor, was found to contribute in a low-cost manner to closing nutrient gaps in Kenya [START_REF] Termote | Role of wild, neglected and underutilized foods in reducing the cost of a nutritionally adequate diet in the eastern region of Baringo District, Kenya[END_REF]. Peach palm (Bactris gasipaes) provides, under low soil fertility and extreme rainfall conditions, starchy fruits with high protein density, rich in monounsaturated oleic acids, carotenoids, vitamin E and potassium [START_REF] Graefe | Peach palm (Bactris gasipaes) in tropical Latin America: implications for biodiversity conservation, natural resource management and human nutrition[END_REF]. Amaranth, as a leafy vegetable, is nutritionally comparable with spinach while showing strong photosynthetic activity and water use efficiency [START_REF] Wang | Breeding of Leafy Amaranth for Adaptation to Climate Change[END_REF][START_REF] Ebert | Potential of Underutilized Traditional Vegetables and Legume Crops to Contribute to Food and Nutritional Security, Income and More Sustainable Production Systems[END_REF].

The drumstick tree (Moringa oleifera) combines the traits of high yield and high nutrient density in essential micronutrients, vitamins, antioxidants and bioavailable iron, making it a good supplement for children and pregnant and lactating women [START_REF] Ebert | Potential of Underutilized Traditional Vegetables and Legume Crops to Contribute to Food and Nutritional Security, Income and More Sustainable Production Systems[END_REF]. All these examples demonstrate how intraspecific biodiversity and the consumption of neglected species and varieties can be essential to nutrition security.

Increasing the number of crops available to local communities, in particular in developing countries, increases the likelihood of obtaining the nutrients needed for healthy and productive lives [START_REF] Declerck | Ecological approaches to human nutrition[END_REF]. [START_REF] Deckelbaum | Econutrition: Implementation models from the Millennium Villages Project in Africa[END_REF] showed that biodiversity and hunger hotspots geographically correspond, reminding us of the link that Jared Diamond unraveled about the spatial relationship between biodiversity availability and society development [START_REF] Diamond | Guns, Germs, and Steel[END_REF]. This evidence, demonstrating the correlation between hunger and biodiversity-losing areas, confirms the need for local biodiverse agricultural systems.

DeClerck et al. ( 2011) further observed that improving functional agrobiodiversity in Kenya reduces anemia incidence, and that interventions supporting environmental sustainability, through biodiversity, can have multiple direct and indirect outcomes on human health and nutritional wellbeing. Similarly, in rice-based aquatic production systems, [START_REF] Halwart | Biodiversity and nutrition in rice-based aquatic ecosystems[END_REF] found that vegetal agrobiodiversity allowed improved biological diversity and diverse nutritional sources for human subjects (calcium, iron, zinc, vitamin A, some fatty acids and limiting amino acids). Moreover, through fish biodiversity, rice yields increase and the presence of several aquatic organisms in rice ecosystems allows a better biological control of vectors and pests. Animal and vegetal agrobiodiversity in rice-based ecosystems increases income through yield growth and lower costs for pesticides through biological control [START_REF] Diamond | Guns, Germs, and Steel[END_REF]. These issues suggest, for tackling malnutrition, but also other aspects of food insecurity, the need to link ecology and agriculture to human nutrition and health.

Agrobiodiversity and resilience for food security

On top of nutritional issues, agricultural biodiversity is an essential component in the sustainable delivery of a more secure food supply. Agrobiodiversity is the outcome of thousands of years of efforts by farmers, selecting, breeding and developing appropriate production systems and methods. It plays a crucial role in productivity and livelihood of farmers, by providing the wide range of resources they need to increase productivity in favorable settings or to adapt to variable conditions.

Biodiversity simplification resulted in an artificial ecosystem that requires constant human intervention, whereas plant biodiversity allows internal regulation of essential functions in natural ecosystems [START_REF] Altieri | The ecological role of biodiversity in agroecosystems[END_REF]. Several nature-and human-related drivers of change threaten the ability of social-ecological systems to maintain vital functions and processes: climate change, natural resources exploitation, habitat depletion, pollution, etc.

Understanding how agrobiodiversity is likely to impact agricultural and ecosystems is key. Climate change is a potent risk to the world's food supply in coming decades, likely to undermine production and driving up prices [START_REF] Godfray | Food security: the challenge of feeding 9 billion people[END_REF]Ingram et al., 2010). Agricultural biodiversity will be absolutely essential to cope with the predicted impacts of climate change. Crop genetic diversity provides partial resistance to diseases, and enables farmers to exploit different soil types and microclimates for a variety of nutritional and other uses [START_REF] Altieri | The ecological role of biodiversity in agroecosystems[END_REF]. Improved resilience, to climatic shocks among others, is observed in highly biodiverse ecosystems [START_REF] Swift | Biodiversity and ecosystem services in agricultural landscapes: Are we asking the right questions?[END_REF][START_REF] Rees | Long-term studies of vegetation dynamics[END_REF]. In Malawi, Mozambique and Zambia, between 26 and 50% of rural households relied on indigenous fruits as a coping strategy during critical seasonal\ hunger periods [START_REF] Akinnifesi | Domesticating priority miombo indigenous fruit trees as a promising livelihood option for smallholder farmers in Southern Africa[END_REF][START_REF] Powell | The role of forests, trees and wild biodiversity for nutritionsensitive food systems and landscapes[END_REF]. Furthermore, biodiversity in agroecosystems accomplishes multiple ecological services beyond the production of food such as: nutrients recycling, hydrological regulation, purification of toxic chemical compounds, etc. For instance, improvement in agroforestry biodiversity reduces nutrient leaching and soil erosion and refurbishes key nutrients from the lower soil layers (FAO, 2011a). To assess the role of agricultural biodiversity in sustainable and secure food production, cross-sectoral approaches are necessary as potential benefits can be manifested at different ecological and human scales (Frison, 2011). Farmers also conserve, and modify their use of, agrobiodiversity to better adapt to different environmental conditions, but also to changing market conditions [START_REF] Pascual | The economics of agrobiodiversity conservation for food security under climate change[END_REF]. In Indonesia, the conservation of high levels of biodiversity in rubber agro-forests helped secure population livelihood during the 2008 fall of rubber prices by providing an alternative source of income from secondary products [START_REF] Powell | The role of forests, trees and wild biodiversity for nutritionsensitive food systems and landscapes[END_REF][START_REF] Feintrenie | Sumatra's rubber agroforests: advent, rise and fall of a sustainable cropping system[END_REF]. Agrobiodiversity can thus be seen as a crucial asset to keep multiple options open. As a general rule, increasing the number of species in a community will enhance the number of functions provided by that community, and will reinforce the stability of the provision of those functions [START_REF] Declerck | Ecological approaches to human nutrition[END_REF].

Bio-economic modelling for biodiversity and nutrition

Modelling activities, capturing diversities

In recent years, there has been a significant development of bio-economic models, enhanced by the recognition of the multifunctionality of agriculture and the multiplicity of objectives assigned to the agricultural policies [START_REF] Janssen | Assessing farm innovations and responses to policies: a review of bio-economic farm models[END_REF]. The subsequent increasing demand for integrated assessment called also for more dialogue and co-operation between scientists from various disciplines, and bio-economic models have been advocated as an adequate tool for such a purpose (Kragt, 2012). Bio-economic models refer to models that couple both an economic and a biophysical component. [START_REF] Brown | A review of bio-economic models[END_REF] more precisely identifies models primarily concerned with 'biological process (. . .) to which an economic analysis component has been added'.

Another kind of model consists of 'economic optimization models which include various biophysical components as activities among the various choices for optimization'. In between, he suggests a third category that integrates in an interactive manner the biophysical and the economic modules. This last category genuinely deserves to be called 'bio-economic'.

At the heart of most bio-economic models lies the paradigm that, for analyzing the relationships and tradeoffs between socio-economic systems and biophysical and ecological processes, and to help evaluate how management actions affect different policy objectives, it is necessary to model activities [START_REF] Flichman | Modelling the Relationship Between Agriculture and the Environment Using Bio-Economic Models: Some Conceptual Issues[END_REF]. What produces biodiversity depletion or soil erosion is not wheat or maize production per se, but the way it is produced. And there are several ways of producing the same product.

The degree of pressure on the environment will depend on the crop selected and its combination with other crops, the tillage technique, the type of soil, the production system, the period of harvest, the seasonality and many other technical issues. It is therefore not adequate to associate a final product with a single simple production function. The relationships between a final product and the inputs associated with its production, highly non-linear because of the large set of possible combinations, might be better captured by considering the variety of activities or production processes.

Land, water, seeds (of different species and varieties), labor, energy, machinery, fertilizer, etc. are taken into account as inputs to the agricultural production. Food are outputs, as well as pollution, changes in landscape, depletion of natural resources, soil erosion, loss of underground water, habitat destruction, biodiversity losses, etc. There are numerous possible combinations of inputs to produce several outputs. Using an example from agricultural production, wheat systems do not only produce grain, but also straw and different types of pollution. They are 'joint products' (Baumgartner et al., 2001;[START_REF] Pasinetti | Essays on the theory of joint production[END_REF]. Thus each activity can produce several products (e.g. grain, straw and pollution), and in turn each product can be produced by several activities (e.g. several ways of producing grain). As a consequence, modeling the relationships between a final product and the 'externalities' become even more challenging to synthesize.

Bio-economic models represent production activities in an explicit manner. A production activity describes a specific production process. Usually called an engineering production function, it describes explicitly the relationships between factors of production and products expressed in physical quantities (e.g., kg fertilizer/ha, m3 water for irrigation, etc.). In agriculture, an activity is defined by the technical coefficients that represent the use of inputs needed to produce different outputs [START_REF] Flichman | Modelling the Relationship Between Agriculture and the Environment Using Bio-Economic Models: Some Conceptual Issues[END_REF]. These engineering production functions, which use primal variables (physical quantities), constitute the essential link between the biophysical and economic processes. Models based on cost functions, which use dual variables (prices), can hardly analyze the relationships between inputs and outputs in a straightforward and proper manner. The fact that one product is obtained through several production activities, explains in part the complex and non-linear relationships between inputs and outputs observed per product, which are difficult to capture mathematically. On the contrary, the average cost can more realistically be assumed equal to the marginal cost when considered per activity. Relationships between inputs and joint products by activity are thus linear functions of Leontief type. The use of engineering production functions creates a strong information demand, requiring data framed in terms of physical input-output matrices. However, thanks to this representation, positive and negative jointness can be simultaneously taken into account. This more direct approach can help assess the joint interactions between biodiversity and nutrition.

Biodiversity in bio-economic modeling

There are basically four approaches to introduce biodiversity or agrobiodiversity in bio-economic optimization models. In a normative approach, it is possible to include biodiversity conservation targets directly in a multiobjective function. Multi-objective optimization models are goal-oriented models, where optimal decisions need to be taken in the presence of trade-offs between two or more conflicting objectives. As argued by [START_REF] Schönhart | Integration of bio-physical and economic models to analyze management intensity and landscape structure effects at farm and landscape level[END_REF], biodiversity conservation targets can also be introduced in the model as constraints. Van Wenum et al. ( 2004) study optimal wildlife management on crop farms using integer programming. They compute a wildlife-cost frontier at the farm level evaluating the optimal trade-off between species richness and total gross margins. Their model derives sets of management activities that maximize farm income under incrementally varying wildlife conservation requirements.

Results provide the extent to which stepwise increases in species richness objectives impact negatively farm profits.

A last approach consists of integrating agrobiodiversity at the core of the model in the definition of the agricultural activities. All the earlier examples of models that consider impacts on biodiversity are based, at least partially, on engineering production functions. It implies defining activities such as obtaining constant marginal costs. Combinations of crops and rotation schemes, in interaction with the environment and agronomic technique, on the farm at the field level have to be considered to specify activities. For example, maize, beans and squash (the indigenous 'American three-sisters') planted simultaneously would be modeled as a specific activity, different from an activity involving only one of the three crops or any other combination. The planting techniques used, either just in the same field or in the same hole, would also be distinguished. Conceptually, this approach by activity would allow setting agrobiodiversity at the core of the model, and better match an understanding of the environmental and nutritional outcomes of diets as system outputs. Indeed, specific environment and nutrition impacts can thus be specified by activity and not by product. However, one strong limitation regards data requirements. Given the wide array of possible combinations, a large number of technical coefficients, which enter the model as external variables, need to be available and properly estimated to result in real improvement to existing modelling exercise.

Joint assessment of nutrition and biodiversity

The increasing demand for integrated assessment, including nutrition (Hammond & Dube, 2012;[START_REF] Frongillo | Measures and indicators for assessing impact of interventions integrating nutrition, health, and early childhood development[END_REF][START_REF] Misselhorn | A vision for attaining food security[END_REF][START_REF] Remans | 7 Linking biodiversity and nutrition[END_REF] calls also for bio-economic models integrating consumer choices and dietary patterns, and subsequent sets of food consumption and nutrition indicators. A nutrition-driven food system, which also ensures that environmental integrity, economic self reliance and social well-being are maintained and enhanced, places people, as consumers, as one of its central focus [START_REF] Burchi | The role of food and nutrition system approaches in tackling hidden hunger[END_REF]. Not only should we be able to determine food and nutrient availability at the farm or food system level, resulting from the use of biodiversity for instance, but we also need to understand and consider how it translates into actual consumption at the household and individual level. To achieve this, models of food consumption patterns and behaviours need to be integrated into the bio-economic models. This type of tool will allow a proper nutritional analysis and evaluation of required changes in the food systems to reach sustainable diets. In the context of developing countries, farm household models offer the conceptual background to expand existing bio-economic farm models, to capture the interactions between ecological dimensions and agronomic decisions with consumers' choices (and acceptability of simulated options in terms of consumers' preferences) and nutritional outcomes. Smallholder farmers are vital for developing countries'

economies, supporting today one-third of humanity (IFAD, 2014). Farm households, while increasingly selling and relying on markets, represent an 'easier to control for' food system at the smallest scale.

In the case of smallholder farmers in developing countries, the deciding entity is both a producer and a consumer. In the existence of market failures, non-separability regarding production and consumption decisions has to be assumed, and a farm-household approach becomes necessary [START_REF] Sadoulet | Quantitative development policy analysis[END_REF]. Several attempts have been made to couple bio-economic and farm-household models [START_REF] Janssen | Assessing farm innovations and responses to policies: a review of bio-economic farm models[END_REF][START_REF] Holden | Non-farm income, household welfare, and sustainable land management in a less-favoured area in the Ethiopian highlands[END_REF][START_REF] Kruseman | Agrarian policies for sustainable land use: bioeconomic modelling to assess the effectiveness of policy instruments[END_REF]Ruben and van Rujven, 2001;[START_REF] Shiferaw | Population pressure and land degradation in the Ethiopian highlands: a bio-economic model with endogenous soil degradation[END_REF] In a normative approach, this approach could help define optimal combinations of activities and resulting diets. In a more positive approach, it could identify through simulation analysis the factors more likely to help attain some of these optimal combinations.

-Conclusions

A wider deployment of agricultural biodiversity is key for the sustainable delivery of a more secure and nutritious food supply. The importance of nutrient diversity for human wellbeing calls for dietary diversification. However, the quality of nutritional supply and human health are in danger because of losses in biodiversity. Biodiversity benefits affect social-ecological systems all along the food value chain, from agricultural activities, food processing and consumption patterns to nutrition and health status. There is a call for system approaches to capture the dynamic processes between and within the food system activities, nutrition and health, and environmental outcomes. Computational complex systems modeling techniques aim at capturing the co-evolution of human and biological systems, and the complexity of human decision-making (Hammond & Dube, 2012)

-Introduction

Over the past 25 years, the international and scientific community has repeatedly attempted to deal with the issue of sustainability. "Our Common Future" (UN, 1987), commonly known as the "Brundtland Report", argues that sustainable development should meet "the needs of the present without compromising the ability of future generations to meet their own needs". It stresses the necessity to implement economic, social, environmental and institutional progress that can be maintained over time. Worldwide concerns about sustainable development are also reflected in the global food security debate, which states that "Food security exists when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food which meets their dietary needs and food preferences for an active and healthy life" (FAO, 1996). The 1996 World Food Summit (WFS) identifies four main determinants of food security: food availability, accessibility to food, food utilization, and the stability over time of the three previous dimensions; depletion in any one of these leads to food insecurity.

The first crucial change from the supply-based food security concept of 1974 (UN, 1975) came with the access-related definition of food security [START_REF] Fao | World Food Security: a Reappraisal of the Concepts and Approaches[END_REF]World Bank, 1986) using Sen's entitlements approach [START_REF] Sen | Poverty and Famines: An Essay on Entitlement and Deprivation[END_REF]. Then, the nutrition approach guided the notion of utilization [START_REF] Staatz | Measuring food security in Africa: conceptual, empirical, and policy issues[END_REF], highlighting the need for quality, including good and culturally accepted feeding practices, food safety and nutritional value. During the same period, Maxwell and Frankenberger (1992) sustain the theory that household access to sufficient and nutritious food at all times is key to food security. Building on the 1986 World Bank report "Poverty and hunger", the stability dimension, related to the temporal dynamics of food insecurity, was explicitly acknowledged.

Associating sustainable agriculture and food security, [START_REF] Speth | Towards sustainable food security[END_REF] Swaminathan was among the first to point out the need for an ecological foundation to food security "to protect basic life-support systems of land, water, flora, fauna, and the atmosphere" (Swaminathan, 1983, p. 37). In 1987, Swaminathan reaffirmed the sustainable food security concept, extending it to encompass both to nutritional and water issues, while [START_REF] Gussow | Dietary guidelines for sustainability[END_REF] were the first to use the term "sustainable diets" to define diets both healthy for the environment and humans. It is clear from this definition that the issue of sustainability of diets closely refers to food and nutrition security. The sustainable diets definition establishes four main goals for the governance of a future sustainable food system: human health and nutrition, cultural acceptability, economic viability and environmental protection [START_REF] Fanzo | Metrics of sustainable diets and food systems[END_REF]. It highlights some crucial elements such as the importance of biodiversity stocks not just for the agriculture and the environment, but also for adequacy to nutritional recommendations and cultural acceptability. The multiple conditions of sustainability clearly encompass several dimensions. These conditions refer to different sets of capital that allow flows of services to be maintained over time. Stiglitz, Sen and Fitoussi (2009) suggest that these welfare-producing services can be sustained over time when stocks of capital (natural, physical, human and social) are transferred to future generations.

The analysis of the sustainability of food security requires a shift towards a multidimensional vision (Pinstrup- [START_REF] Pinstrup-Andersen | Food security: definition and measurement[END_REF], but also a transversal approach across the multiple activities leading to diets. Achieving both sustainability and food security requires more than focusing on agriculture or on markets or on household food baskets, but to look at the overall food system [START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF]. Sustainable food systems are key for assuring sustainable food security (FAO & Bioversity International, 2012), and they cannot be pursued in the absence of food and nutrition security [START_REF] Buttriss | Sustainable diets: Harnessing the nutrition agenda[END_REF]. Food security and food system sustainability are then indispensable prerequisites to each other and they need to be jointly analyzed.

Policymakers and stakeholders play a key role in the governance of future sustainable food systems, at a different spatial scale. They need evidence-based scientific information to define policy and implement actions [START_REF] Barrett | Measuring Food Insecurity[END_REF]. The aim of this chapter is to develop a conceptual framework, applied to the Mediterranean region, which links concepts, methods and metrics, for a multidimensional joint analysis of food and nutrition security and food system sustainability. Building on the resilience literature, the vulnerability approach [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] provides a systemic causal pathway to analyze the impacts of the main drivers of change on specific food security and nutrition outcomes. It allows understanding and assessing the conditions of sustainability of the food system. This chapter provides the conceptual background to develop metrics, relying on evidence-based scientific knowledge, to inform all stakeholders, particularly policymakers, on response interventions to major changes at national and regional scale, in order to maintain the ability of the system to provide food security and good nutrition over time, while taking into account environmental, social and economic constraints and assets.

We first introduce the Mediterranean context and briefly review the main issues related to food and nutrition security and food system sustainability in the region.

Developed from natural disaster and sustainability sciences, the vulnerability conceptual framework is presented as a valid approach to capture and model food system sustainability. We then expose the associated metrics -or information system -to quantify vulnerability that integrates three essential components: exposure, sensitivity, and adaptive capacity [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]. We finally discuss the utility of this approach with examples of its possible application to Mediterranean countries.

-Food Insecurity and Environmental Unsustainability: A joint regional analysis

Changes in dietary patterns and food insecurity

Globally, more than 2 billion people are food insecure, either undernourished, malnourished or overnourished [START_REF] Ciheam | Towards the development of guidelines for improving the sustainability of diets and food consumption patterns: the Mediterranean Diet as a pilot study[END_REF][START_REF] Strang | Investing in the future: A united call to action on vitamin and mineral deficiencies: Global Report 2009[END_REF]WHO, 2013).

Concurrently, there is consensus among the international and scientific community on the non-sustainability of the western agrofood system, in terms of its impacts on natural resources and ecosystems, and on human health with increasing prevalence of non-communicable diet-related diseases. The Mediterranean region has been identified as one of the main critical hotspots of environmental unsustainability due to intense human activity and agricultural exploitation [START_REF] Capone | Food consumption patterns and sustainable natural resources management in the Mediterranean region[END_REF]Salvati, 2013). A large part of its population can also be considered food insecure. Using United Nations (UN) anthropometric and population composition data 3 , out of a total population of about 500 million, it is possible to estimate that at least 215 million adults and children (44% of total population) are "qualitative and quantitative foodinsecure" in the Mediterranean region 4 , 5 . The geographical zone represents an interesting testing area of study in which to carry out a multidimensional analysis of the inter-connected factors that characterize food insecurity and environmental unsustainability. In this section, we present a joint analysis of the current situation and show how both issues intersect. [START_REF] Rastoin | Sécurité alimentaire en Méditerranée: Un enjeu géostratégique majeur[END_REF].

Obesity is closely linked to dietary behavior and socio-economic determinants, but also to agricultural policies, production systems and food chain characteristics [START_REF] Delpeuch | Globesity: a planet out of control?[END_REF]. In the Northern Mediterranean countries, these diet-related pathologies are the symptoms of an overconsumption of meat (especially red meat), dairy products and eggs [START_REF] Padilla | Dietary patterns and trends in consumption[END_REF], with a tendency towards overconsumption of energy-rich and nutrient-poor foods (Darmon & Soler, 2013). In Southern Mediterranean, the double burden phenomenon represents the chronic phase of a nutrition transition. Statistics show a change of diet towards a regime that is richer in animal proteins and fats, at the expense of dietary diversity and food providing important micronutrients [START_REF] Popkin | The Nutrition Transition in the Developing World[END_REF]. At the same time, supply shortage and struggle for access to food remain persistent for large cohorts of individuals. Another feature of the nutrition transition in the Southern Mediterranean countries is the change in the share of energy sources derived from added sugars, with increased intake of simple carbohydrates and refined sugars [START_REF] Drewnowski | The Nutrition Transition: New Trends in the Global Diet[END_REF]) and, in particular, a sharp increase in levels of simple sugar consumption through processed industrial products (drinks, biscuits, desserts, etc.) [START_REF] Padilla | Dietary patterns and trends in consumption[END_REF].

Hence nutrition transition and malconsumption i are the two major food phenomena leading to diet-related diseases in the Mediterranean. Nutrient-poor "pseudo foods" [START_REF] Winson | Bringing political economy into the debate on the obesity epidemic[END_REF] with high levels of vegetable oils, animal fats, sugar and salt permeate the global food system [START_REF] Popkin | Using research on the obesity pandemic as a guide to a unified vision of nutrition[END_REF]. Long-established dietary patterns and traditions using local staples are being replaced with western-style highly processed products [START_REF] Pingali | Westernization of Asian diets and the transformation of food systems: implications for research and policy[END_REF]. This is the case in emerging economies that are experiencing several phenomena simultaneously, such as increased urbanization, household income growth, greater market penetration by foreign brands, global supermarket and food service chains, expansion of advertising and mass media, and highly competitive prices (Sage, 2012). These dynamics lead to qualitative changes in diets and thus new food security issues, together with changes in lifestyle and work environment, with a growing tendency towards sedentary jobs and physical activity increasingly being limited to leisure time [START_REF] Gil | Economic development and food consumption in Mediterranean countries[END_REF]. These changes in diets contribute, as causal factors, to the rising incidence of nutrition-related noncommunicable diseases, such as heart disease, cancer, diabetes and obesity.

The associated issue of environmental unsustainability

These dietary changes and the increasing incidence of related diseases coincide with major transformations in the agricultural and food systems, which have become more global and complex. These evolutions in food behavior patterns and in industrial production and processing have joint social, economic and environmental impacts. It is a fact that the nutritional characteristics of diets are directly related to environmental conditions, which are consequences of the production system associated with current food consumption patterns. The question is to understand to which extent. The environmental impact of the current agrofood system is a widely debated question. [START_REF] Darmon | Carbon footprint and nutritional quality of diets in France[END_REF], for instance, observe a positive correlation between calorie intake and greenhouse gas emissions. In any case, it should be noted that the Mediterranean agrofood sector represents 25% of the global Ecological Footprint of the region (Global Footprint Network, 2012).

The current shift from diverse farming systems to ecologically simplified ones, mainly based on cereals, contributes to micronutrient deficiency, poorly diversified diets and thus malnutrition in developed, as well as in developing countries [START_REF] Frison | Agricultural biodiversity, nutrition, and health: Making a difference to hunger and nutrition in the developing world[END_REF]Graham et al., 2007;[START_REF] Negin | Integrating a broader notion of food security and gender empowerment into the African Green Revolution[END_REF][START_REF] Remans | Assessing Nutritional Diversity of Cropping Systems in African Villages[END_REF][START_REF] Welch | A new paradigm for world agriculture: meeting human needs: Productive, sustainable, nutritious[END_REF]). An important negative outcome of intensive production, in addition to environmental damage such as soil depletion and erosion, and pollution of surface and groundwater, is the narrowing of biodiversity base through the use of only the most profitable varieties.

Many of the processes and much of the equipment used in the food industry have been developed to transform staple foods with specific characteristics (e.g. size, color group, quality category, etc.). As a consequence, despite an apparent diversity of the final products available on the market for consumers, genetic resources diversity tends to shrink. Current industrial production systems favor limited varieties and monocultures to the disadvantage of biological diversity [START_REF] Esnouf | Food System Sustainability: Insights from DuALIne[END_REF]. The issue of biodiversity loss is related both to environmental concerns and to health and nutrition issues, because of its link with insufficient diet diversity, micronutrient deficiency, and unhealthy food habits [START_REF] Burlingame | Food composition is fundamental to the cross-cutting initiative on biodiversity for food and nutrition[END_REF]. The importance of food variety and composition, especially in terms of genetic resources, is increasingly acknowledged. Differences in nutrients between varieties have a major impact on nutrient intakes; higher consumption of one variety over another can lead to adequacy or deficiency in certain micronutrients. For this reason, nutrition research looks at both the food composition and consumption dimensions [START_REF] Burlingame | Food composition is fundamental to the cross-cutting initiative on biodiversity for food and nutrition[END_REF].

The alarming rate of biodiversity loss and ecosystem degradation, and the consequent negative impact on food and nutrition security, also provide strong reasons to reconsider the food systems and diet approaches. It is necessary to develop and promote strategies for sustainable food regimes, emphasizing the positive role of biodiversity to reverse or mitigate the phenomena that cogenerate negative effects on human nutrition and health [START_REF] Burlingame | Food biodiversity and sustainable diets: implications of applications for food production and processing[END_REF]. However, measuring food and nutritional biodiversity is a difficult task; the INFOODS network developed metrics that need a large amount of data, which are difficult to collect.

The environment throughout the entire geographic area of the Mediterranean is at risk, threatened by the intensive exploitation of its natural resources, particularly water [START_REF] Lutter | Water Management Indicators -State of the Art for the Mediterranean Region[END_REF][START_REF] Roson | Water scarcity and virtual water trade in the Mediterranean[END_REF]UNEP, 2006). Considering the increasing issue of drought in the region, the intensification of water requirements for food is a major concern [START_REF] Capone | Food consumption patterns and sustainable natural resources management in the Mediterranean region[END_REF]. The high water demand of the Mediterranean food system reveals a deficit in terms of virtual water exchange for agrofood products (Mekonnen & Hoekstra, 2011) 8 . Water consumption trends are directly related to food consumption patterns since food products bring with them an internal quantity of water that differs by foodstuff origin, quality and quantity. Water requirements for plant and animal products vary widely. Red meat and dairy products, for example, are considered highly water-consuming compared to crop production.

Thus, the quantity and types of food demanded strongly implicate the extent of water allocated and used for agriculture and related production activities [START_REF] Lundqvist | Saving water: from field to fork: curbing losses and wastage in the food chain, SIWI Policy Brief[END_REF]. Water consumption is therefore also connected to nutritional composition of food consumed and strictly related to life habits and to drivers of change affecting the food system.

The relationship between unhealthy foods and highly environment-impacting foodstuff is tentatively captured by the Barilla Center's Double Pyramid (Barilla Center for Food and Nutrition, 2010). Some argue that the more frequently recommended healthy food corresponds also to lowest environment impacting products, and vice versa. Consumption of red meat is, for example, often considered the heaviest variable affecting the sustainability of food systems and consumed in excessive amounts in developed countries [START_REF] Fao | Livestock's long shadow: Environmental issues and options[END_REF][START_REF] Lang | Looking Back, Looking Forward: Sustainability and UK food policy 2000-2011[END_REF]. However, evidence is mixed with regard to the general alignment of environmental and nutritional recommendations. For instance, [START_REF] Vieux | High nutritional quality is not associated with low greenhouse gas emissions in self-selected diets of French adults[END_REF] show that high nutritional quality is not always associated with low greenhouse gas emissions.

Certainly no single food can encompass the wide range of both nutritional and environmental recommendations, without even mentioning economic viability and social acceptability constraints. A myriad of factors affecting both actors and activities within the food system explain the nutritional and environmental outcomes of dietary behaviors. Providing a clearer picture of the circular dynamics between environmental, health, economic and social drivers can help not only to measure impacts or progress, but also to understand interactions, and thus aid decision making.

We suggest tackling this complex challenge by applying the vulnerability framework to the changes affecting the agrofood system.

Building on [START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF], we defend an approach to metrics, which switches not only from the "what we get" (food security outcome approach) to the "what we do" approach (food systems-activities approach) (p. 419), but which also considers the "what happens" side (food system-drivers interactions). The Mediterranean region presents several factors of change affecting food security and environmental sustainability. The multiple issues related to food insecurity and unsustainability that have been exposed above for the Mediterranean region can be analyzed from a multidimensional perspective, as a series of issues or hotspots of vulnerability of the different national agrofood systems, and integrated within a conceptual framework linking concepts, methods and metrics.

-Vulnerability for a multidimensional and dynamic system approach

Mechanics of change and sustainability

According to the definition of agro-ecosystem sustainability coined by [START_REF] Conway | Agroecosystem analysis[END_REF], "Sustainability is the ability of a system to maintain productivity in spite of a major disturbance, such as caused by intensive stress or a large perturbation" (p.

35). Consistently with the literal English usage of the verb "to sustain", [START_REF] Hansen | Is agricultural sustainability a useful concept?[END_REF] further interprets sustainability as a system's ability to continue through time.

If sustainability is the dynamic ability of a given system to maintain or enhance its essential outcomes over time and space, then the concept of vulnerability can provide the elements to understand the mechanisms affecting the activities of the system [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF].

The United Nations Development Programme (UNDP) defines vulnerability as the "degree of loss to each element should a hazard of a given severity occur" (1994, p.

49), i.e. the extent to which an individual or system or geographic area is damaged in relation to a given change. [START_REF] Downing | Assessing socioeconomic vulnerability to famine: Frameworks, concepts, and applications[END_REF] states that "Vulnerability is the composite of two prospects: risk of exposure and risk (or magnitude) of consequence" (p. 11).

The exposure to hazardous events is different from the magnitude of the consequences that result from that exposure. The vulnerability approach further evolves with [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF], who established three main components to vulnerability: exposure, sensitivity and adaptive capacity. Adaptive -or copyingcapacity corresponds to the responses that it is possible to implement. The theoretical basis for this evolution is to be found essentially in the theory of abilities and capabilities [START_REF] Sen | Poverty and Famines: An Essay on Entitlement and Deprivation[END_REF].

The vulnerability assessment is today widely acknowledged as composed of three dimensions [START_REF] Adger | Institutional adaptation to environmental risk under the transition in Vietnam[END_REF][START_REF] Adger | Vulnerability[END_REF][START_REF] Adger | Uncertainty in adaptive capacity[END_REF][START_REF] Allison | Vulnerability of national economies to the impacts of climate change on fisheries[END_REF]Cinner et al., 2011;Gallopin, 2006;[START_REF] Kelly | Theory and practice in assessing vulnerability to climate change and facilitating adaptation[END_REF][START_REF] Ipcc | Climate change 2001: Impacts, adaptation, and vulnerability[END_REF][START_REF] Grafton | Adaptation to climate change in marine capture fisheries[END_REF][START_REF] Smit | Adaptation, adaptive capacity and vulnerability[END_REF]: exposure and sensitivity to single or multiple stressors, and the adaptive capacity to cope with these. [START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF] adopted such a conceptual framework to quantify the anthropic effects on coral reefs and national food security, developing a national-level vulnerability index. In the case of the fresh fruit and vegetable value chains, the vulnerability approach was adopted to assess the strengths and weaknesses of Mediterranean production zones facing an increasing competition from South East Mediterranean countries [START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF]. The aim was to build an inter-regional diagnostic comparison by means of a Regional Vulnerability Index (RVI).

Vulnerability is a relative measure, and the exposure of individuals/systems/regions is related to their specific conditions. Similarly, the magnitude of the consequences from this exposure is linked to these particular characteristics and their associated sensitivity. Most adaptive capacity analyses tend to be specific to a place and context while linked across scales [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF], and vulnerability is most frequently assessed at national levels [START_REF] Allison | Vulnerability of national economies to the impacts of climate change on fisheries[END_REF][START_REF] Brooks | The determinants of vulnerability and adaptive capacity at the national level and the implications for adaptation[END_REF][START_REF] Pelling | Small island developing states: natural disaster vulnerability and global change[END_REF]. The benefits of assessing vulnerability at the national level are that results can influence national-level policy responses and adaptive management strategies [START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF].

A causal-factor approach

One key conceptual element is a clear distinction between causal events and outcomes [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF]. Following the introduction by [START_REF] Sen | Poverty and Famines: An Essay on Entitlement and Deprivation[END_REF] of the notion of accessibility beyond availability as a main determinant of famine, the analysis of food security shifted from a study of the sole natural causes to the inclusion of societal causes (Blaikie et al., 1994). The vulnerability framework was indicated to describe and assess the multifaceted socioeconomic determinants of famine [START_REF] Borton | Mapping vulnerability to food insecurity: Tentative guidelines for WFP offices, Relief and Development Institute[END_REF]Maxwell & Frankenberger, 1992;Middleton & O'Keefe, 1998;[START_REF] Ribot | The causal structure of vulnerability: its application to climate impact analysis[END_REF][START_REF] Swift | Why are Rural People Vulnerable to Famine?[END_REF] (as cited in [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF]. The vulnerability approach, based on natural disaster assessment, was then transposed to societal causes for the analysis of food insecurity. In particular, [START_REF] Chambers | Editorial Introduction: Vulnerability, Coping and Policy[END_REF] and [START_REF] Downing | Assessing socioeconomic vulnerability to famine: Frameworks, concepts, and applications[END_REF] made considerable efforts in converting Sen's analysis into assessment methods. The main result was the expression "vulnerability to famine" (p.

233), which became widely popular. It was understood in direct relation to the final outcome. However, [START_REF] Downing | Assessing socioeconomic vulnerability to famine: Frameworks, concepts, and applications[END_REF] clearly stated that vulnerability is "a relative measure, for a given population or region, of the underlying factors that influence exposure to famine and predisposition to the consequences of famine" (p. 18), aiming at identifying elements for a causal factor analysis.

In the food security context, the Food and Agriculture Organization specified that vulnerability is the relationship between risks, resulting shocks and resilience to these (FAO, 2004). The coupled risk-shock component affects population wellbeing and food security, while resilience concerns the strategies implemented to mitigate the impact of the shocks. Vulnerability is understood as directly correlated to the impact of shocks and is inversely correlated to resilience (FAO, 2004). While the natural disaster management approach to vulnerability involved the identification of a degree of damage on populations or economic assets, food security specialists applied vulnerability to measure the intensity of the state of food insecurity or famine [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF]). Hence, it is possible to define the FAO vulnerability approach to food security analysis as a direct "outcome approach", whilst the natural disaster method is rather a "causal factor approach", describing the interactions leading to the final outcomes.

Given the wide and complex sequence of phenomena involved in food insecurity and environmental unsustainability, the causal factor specification can also help to distinguish several vulnerabilities of specific issues or outcomes. It allows a dynamic analysis of the particular issues of vulnerability, instead of a static identification of vulnerability to a broad and general final outcome. Furthermore, a broad understanding of vulnerability on wide range of sectors or issues would not be sufficiently focused to implement actions [START_REF] Ionescu | Towards a formal framework of vulnerability to climate change[END_REF]Leurs, 2005).

Regarding the multidimensionality of the concepts of food security and sustainability, assessments based on one element or one dimension are no longer considered sufficient [START_REF] Aubin | A critical panorama of methods used to assess food sustainability[END_REF]. There is a rising call for new types of systems analysis and modeling tools (Nicholson et al., 2009). The fragmentation of the broad concept of vulnerability in an integrated general framework is a first response to this need.

Vulnerability has evolved as a term of art and a conceptual framework to implement assessment methods in different research areas, such as climate impact analysis (Timmerman, 1981), disaster management (UNDRO, 1979), food security [START_REF] Chambers | Editorial Introduction: Vulnerability, Coping and Policy[END_REF][START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF], and sustainability science [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]. The analysis of vulnerability can provide a conceptual and methodological approach to the understanding of sustainability. It offers a logical conceptual basis and method upon which to build a modeling causal framework that raises awareness on: vulnerable people or entities to shocks; how and where the shocks modified the living conditions; which are the response strategies; the identification of the multiple metrics that assess the phenomena. Additionally, [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] referred to vulnerability assessment as a coupled human-environment system approach and reaffirmed the role of sustainability and global change science in improving the bonds between the science problem and decision-making needs.

-Methodological steps for the assessment of Vulnerability

Exposure

Building on sustainability and natural disaster sciences, exposure is considered as the degree to which a system experiences environmental or socio-political stress [START_REF] Adger | Vulnerability[END_REF], including frequency, magnitude, duration and the areal extent of the hazard [START_REF] Burton | The Environment as Hazard[END_REF]. It can thus be interpreted as the likelihood of experiencing stress or perturbations [START_REF] Downing | Assessing socioeconomic vulnerability to famine: Frameworks, concepts, and applications[END_REF]. For the purpose of this work, we define exposure as the degree to which a system or a country is subjected to changes directly causing or indirectly prompting food insecurity and environmental unsustainability. For instance, in a context of dependency on cereal imports, the share of cereals in total consumption can indicate the degree of exposure to cereal price volatility. Exposure is directly correlated with vulnerability.

Sensitivity

Sensitivity can be defined as the consequence of the exposure to a stress. It is the degree to which a system is modified or affected by the perturbations or the outcome of an unwanted event to which the system is exposed [START_REF] Adger | Vulnerability[END_REF]. It can be understood as the likelihood of experiencing different magnitudes of consequences of exposure to a stress or perturbation [START_REF] Downing | Assessing socioeconomic vulnerability to famine: Frameworks, concepts, and applications[END_REF]. For instance, price elasticities for cereals may represent the sensitivity to fluctuating international cereal prices, since they represent the effective impact of the exposure. Indicators of sensitivity are generally measuring impacts. As for exposure, sensitivity is directly correlated with vulnerability.

Adaptive capacity and resilience

The third component of vulnerability, related to adaptive capacity, was defined as the potential of the system to respond to changes [START_REF] Adger | New indicators of vulnerability and adaptive capacity[END_REF][START_REF] Burton | From impacts assessment to adaptation priorities: the shaping of adaptation policy[END_REF][START_REF] Ipcc | Climate change 2001: Impacts, adaptation, and vulnerability[END_REF]. [START_REF] Cinner | Vulnerability of coastal communities to key impacts of climate change on coral reef fisheries[END_REF] and [START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF] propose to disaggregate adaptive capacity into several categories such as assets, flexibility, learning, and social organization. In physics, resilience is the resistance of an object to a given shock. According to [START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF], the concept of resilience is applicable to biology and human sciences as the resistance of an individual or a community to an external stress. For instance, when coupled, exposure and sensitivity negatively affect people's welfare and food security status. In the case of food price volatility, resilience contains all the coping strategies that can be implemented or are already implemented to avoid exposure to risks and minimize impact sensitivity to the shock, in order to overcome detrimental effects. National and global institutions, for instance, by means of food price protection policies, safety nets and subsidies, can encourage these strategies.

In an institutional context, resilience can represent stakeholders' reactive capacity to cope with changes. Stakeholders can respond with coping and adapting strategies to rule economic, finance, social institutional changes [START_REF] North | Institutions[END_REF]. Sen (1985) similarly identifies for individuals the capacity to manage opportunities deriving from risk effects, by means of the concept of capabilities. The stakeholders, searching in their natural, human, physical and social assets, take the opportunity of the environmental changes, transforming these resources in capabilities, which allows overcoming the shocks' impacts and to be prepared for the next risks. For these characteristics that identify resilience (or adaptive capacity), the concept is often associated with sustainability [START_REF] Conway | Agroecosystem analysis[END_REF][START_REF] Strunz | Is conceptual vagueness an asset? Arguments from philosophy of science applied to the concept of resilience[END_REF]. While vulnerability is directly associated with risks and shocks impacts, resilience is inversely correlated with vulnerability (FAO, 2004). People who overcome negative impacts of changes (and end up in an even better situation) would be resilient; those suffering from the effects of the modifications would be considered as vulnerable [START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF].

Calculating a Vulnerability score

In [START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF], the estimation method is based on the capabilities approach;

vulnerability is then assessed solely on the one component of adaptive capacity/resilience. In a more general framework this approach could be also associated with the exposure and sensitivity dimensions. The order and the signs used for the methods of calculation of vulnerability, define the relationships between the three components. However, in a metric-identifying approach, the indicators come from different sources and disciplines, and are expressed in different units of measurement. Index values then need to be standardized or normalized. In many cases (Cinner et al., 2011;[START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF] The Economist Intelligence Unit, 2013), data normalization is based on minimum and maximum values in the dataset, and places on a scale from 0 to 1 (from 0 to 100 for the GFSI, 2012) using the typical normalization method "min-max" [START_REF] Adger | Uncertainty in adaptive capacity[END_REF]OECD, 2008):

i(X) = (X -Xmin)/(Xmax -Xmin) (3.1)
In this formula Xmin and Xmax are, respectively, the lowest and highest values for any given indicator. The normalized value is then transformed from a 0 to 1 value to make it directly comparable with other indicators. This means that the indicator with the highest raw data value will score 1, while the lowest will score 0.

In the examples referred to, the indicator scores are normalized and then aggregated across categories to enable a comparison of broader concepts across countries.

Normalization rebases the raw indicator data to a common unit so that it can be aggregated.

Finally, in our specific case the n particular vulnerabilities will be calculated following this formula:

V = [(E -Emin / Emax -Emin) + (S -Smin / Smax -Smin) -(AC -ACmin / ACmax -ACmin)].
(3.2)

Where V = vulnerability, E = exposure, S = sensitivity and AC = adaptive capacity.

Another issue that has to be considered is the quantitative relevance, or weight, that is associated with the different components. Different metric systems often rely on equal weights, leaving to policymakers, practitioners and stakeholders the opportunity to apply a goal-or priority-oriented weighting system [START_REF] Saaty | Decision Making for Leaders: The Analytical Hierarchy Process for Decisions in A Complex World[END_REF]Hammond et al., 1999;[START_REF] Mcclanahan | Conservation action in a changing climate[END_REF]The Economist Intelligence Unit, 2013).

Based on this approach, it would be possible to rank the Mediterranean countries in relation to their exposure, sensitivity and adaptive capacity vis-à-vis changes affecting agrofood systems in their food and nutrition security outcomes.

-Discussion of the approach

Metrics, analysis and prospective

The vulnerability approach stresses the need for methods and metrics that do not just express final results or outcomes, but provides a system of information that can be interpreted in a dynamic framework modeling interactions between different drivers.

In particular, the vulnerability framework can be disaggregated in several dimensions according to the different drivers of change considered: vulnerability to climate change, vulnerability to price volatility, vulnerability to demographic transformations, etc. The integrated fragmentation of the broad vulnerability into specific vulnerabilities represents a response to the lack of causal factor analysis.

As mentioned above, each specific vulnerability can be further broken down into exposure, sensitivity and adaptive capacity. However, both the sensitivity and adaptive capacity dimensions of the system have to be assessed according to specific outcomes or services provided by the food system that need to be maintained over time. For instance, access to food may be jeopardized in the short term by high food price volatility; however, food supply might not be affected in the same way or to the same extent. Thus, problematic issues or hotspots, related to the agrofood system and local context, need to be specified. Three stages of causal factor analysis can be established through the vulnerability framework. In a nutshell, the framework allows organizing evidence-based information and aiding decision-making by clarifying sequential dynamics, while allowing for prospective or forward-looking analysis.

Therefore, it is important to define issues and challenges of food security and sustainability before choosing assessment methods [START_REF] Aubin | A critical panorama of methods used to assess food sustainability[END_REF]. The qualitative identification of the problematic issues, and then of the variables to assess vulnerability, can be obtained through a hierarchical analysis [START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF], previous field observations (Cinner et al., 2011;[START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF], a literature review and expert consultation, and using statistical methods such as Principal

Components Analysis [START_REF] Jolliffe | Principal Component Analysis[END_REF].

The vulnerability framework can lead, for example through participatory methods, to the identification of a system of indicators and appropriate metrics, offering a method to capture complexity and interconnectedness between phenomena [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]. Furthermore, since indicators inform action [START_REF] Barrett | Measuring Food Insecurity[END_REF], they are essential to establish the communicative link between science and policymakers. One essential aim of the vulnerability analysis remains in the identification of the response opportunities for decision-making [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF].

To summarize, several functions can be attributed to the vulnerability approach such as: a holistic and novel assessment framework and a dynamic tool for sustainability sciences; a geographical-based approach involving the participation of local stakeholders; a multiple factor analysis allowing interdisciplinary research on complex and systemic phenomena; a scheme to conceptualize and develop metrics, in a system of information and response opportunities for decision making; a methodology to draw evidence-based knowledge; a predictive framework to anticipate consequences of hazards and changes [START_REF] Watts | Hunger, famine and the space of vulnerability[END_REF][START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Adger | Vulnerability[END_REF]Fussel, 2006;[START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF][START_REF] Locatelli | Facing an uncertain future: How forests and people can adapt to climate change[END_REF][START_REF] Sonwa | Vulnerability, forest-related sectors and climate change adaptation: The case of Cameroon[END_REF]. The main advantages of a vulnerability approach to the analysis of sustainability of food system activities are summarized in Table 1.

Identifying issues and dealing with multidimensionality

Limits to this conceptual approach depend strongly on the level of accuracy of the application. The main risk is the lack of a genuine causal factors analysis that can be avoided by disentangling the multiple vulnerabilities and their components. Thus, one crucial element in the application of the vulnerability approach resides in the level of accuracy in defining the problematic issues that are, in our specific case, driven by nutrition and food security concerns of the agrofood system.

Furthermore, scholars and practitioners highly focused in one specific scientific discipline may be skeptical with regard to the large amount of variables. However, Developing Metrics 1. Providing information and interpretation of the phenomena for decision making [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Adger | Vulnerability[END_REF][START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF][START_REF] Sonwa | Vulnerability, forest-related sectors and climate change adaptation: The case of Cameroon[END_REF] 2. Identifying complexity and interconnectedness of the phenomena [START_REF] Watts | Hunger, famine and the space of vulnerability[END_REF][START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] 3. Increasing scientific knowledge through vulnerability assessment [START_REF] Sonwa | Vulnerability, forest-related sectors and climate change adaptation: The case of Cameroon[END_REF]Fussel, 2006;[START_REF] Locatelli | Facing an uncertain future: How forests and people can adapt to climate change[END_REF] Analysis 4. Allowing information analysis through quantitative and qualitative data and novel methods [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] 5. Allowing the multiple factor analysis for an interdisciplinary understanding of vulnerability [START_REF] Adger | Vulnerability[END_REF] 6. Providing a dynamic tool applied to Sustainability science [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] Prospective 7. Further opening the causal interpretation rather than analyzing just the final outcomes of a phenomenon [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF] 8. Representing the opportunity to involve regional stakeholders in a place-based analysis and collaborative assessment (geographical approach) [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF] 9. Anticipating and predicting new hazards and changes [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Adger | Vulnerability[END_REF][START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF] the development of a multidimensional metrics framework can open a stimulating scientific debate involving experiences from several disciplines and feed the scientific knowledge base. Indeed, as observed in sustainability science and resilience thinking, inter-and trans-disciplinary communication is strictly linked to problem solvinginstead of puzzle-solving -and related to participative creativity instead of dogmatism [START_REF] Strunz | Is conceptual vagueness an asset? Arguments from philosophy of science applied to the concept of resilience[END_REF]. So, the development of the framework aims to create a flexible tool that can be adapted and modeled (as for a weighting system) to different users' and to different policy purposes related to nutrition and food security concerns. The involvement of the stakeholders is key to building up the framework and to assigning hierarchy to the indicators [START_REF] Aubin | A critical panorama of methods used to assess food sustainability[END_REF].

In conclusion this scheme provides a multidimensional vulnerability framework to jointly assess nutrition and food insecurity and unsustainability. Starting from a specific geographical region, it represents a tool for policymakers. The Mediterranean geographical area, as a physical space where several environmental, social and economic and nutrition hotspots of vulnerability persist over time, offers a first case of application. The last subsection presents an analysis of some representative interactions between drivers of change, and food and nutrition security issues, together with the description of the resulting exposure, sensitivity and adaptive capacity.

Examples of application

Application of the vulnerability assessment framework requires specifying the context and the issues of concern. These can be identified by literature review or participative expert consultation. The analysis of each specific issue or hotspot of vulnerability (of a given geographical area) allows us to establish from which point of the causal sequence of phenomena, the components of exposure, sensitivity and adaptive capacity can be applied.

For the sake of illustration, we provide three examples of how to apply the vulnerability model to the specific geographical Mediterranean region. Given the nutrition and food security-driven perspective of this work, three main issues critical to the food system, namely supply, accessibility and nutritional value, are assessed, considering the three components of vulnerability. Each issue is analyzed against three different landscape drivers of change, respectively climate change, price volatility and nutritional transition and changing consumption patterns. This selection of driver/issue combinations, restricted to three for the sake of illustration, does not presume that the drivers cannot have impacts on several issues.

Food supply-related vulnerability to climate change.

National food supply rests on food production, stocks and imports (minus exports). It relies also on quantities used from feed, seeds and transformation. Depending on the agrofood policy strategies and on their financial system conditions, a national food system can be vulnerable because of several factors or drivers affecting food supply.

The conceptual model provides an approach that develops a series of questions. A

-Conclusions

While securing food security is considered a global priority, there is contemporary widespread consensus about the importance of sustainability as a goal for food systems. This chapter provides a conceptual hierarchical framework for modeling the complex relationships between food and nutrition security and sustainability. It initially analyzed the internationally acknowledged concepts of sustainable development and food security, describing the interconnectedness between them that recent notions such as sustainable food security or sustainable diets try to capture.

Relying on an approach of the concept of sustainability as a system property allowing a desirable state to be "sustained" over generations, assessment methodologies should reflect the conditions of a system from a holistic and dynamic perspective. Calling on elements from the vulnerability and resilience literature, the proposed framework sequentially disentangles the exposure, sensitivity and copying/adaptive capacities of a specific food system to identified stressors or drivers of change jeopardizing critical food and nutrition security outcomes.

This approach entails also the assessment of sustainability with regard to a suitable temporal and spatial scale. Drivers affecting the sustainability of the food systems have multiple origins. The proposed framework hierarchically clarifies the different scale at which drivers and issues interact in a circular way with feedback loops. While suitable for expressing the global food-related concerns of a geographical region, it points out the need for assessment tools adapted to context-specific questions. Main data and general insights of the situation of the Mediterranean region help underline the main critical issues related to food and nutrition security facing the agro-food system in the region.

A quantitative method is proposed for assessing sustainability of food and nutrition outcomes by means of a precise correlation between the three components of exposure, sensitivity and adaptive capacities, which can ultimately be aggregated in a composite index. The joint assessment of food insecurity and unsustainability can be expressed through the language of vulnerability and resilience, as the degree to which a system is exposed and sensitive to dynamic phenomena, while considering its capability to respond and adapt. This approach provides the concepts fundamental to the development of potential indicators or metrics of sustainable diets and food systems, whose primary goal is to ensure food security and good nutrition for a healthy and active life.

Preface to Chapter 4

The processes underlying environmental, economic and social unsustainability derive in part from a shared food system. Building sustainable food systems has become a key endeavor to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems act as complex social-ecological systems, involving multiple interactions between human and natural components.

Policy needs to strengthen the perception of humanity and nature as interdependent and interacting. The systemic nature of these interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system that will ensure that its essential outcomes will be maintained or Agriculture and food systems are at the center of the debates around sustainability.

The processes underlying environmental, economic and social unsustainability derive in part from a shared food system. The increase in food supply has come with important trade-offs. Processes along the food chain, from agricultural production to food consumption, produce other outputs than food that are returned to the natural environment, such as pollution or waste. Food waste only would represent around 3-5% of global warming impacts, more than 20% of biodiversity pressure, and 30% of all of the world's agricultural land (European Commission, 2014). Meanwhile, 842 million people still suffer from undernourishment (FAO, 2013a) while obesity has become a significant public health issue with 500 million obese adults [START_REF] Finucane | National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9•1 million participants[END_REF]. Building sustainable food systems has become a popular motto and key endeavor to redirect our food systems and policies towards better-adjusted goals and improved societal welfare.

A sustainable food system can be defined as one that "provides healthy food to meet current food needs while maintaining healthy ecosystems that can also provide food for generations to come, with minimal negative impact to the environment; encourages local production and distribution infrastructures; makes nutritious food available, accessible, and affordable to all; is humane and just-protecting farmers and other workers, consumers, and communities" [START_REF] Story | Food systems and public health: linkages to achieve healthier diets and healthier communities[END_REF]. The food system is highly complex, driven by many economic, socio-cultural and environmental factors, which are both internal and external to its boundaries. The systemic nature of these interactions calls for systems approaches and integrated assessment tools to guide change.

Many intricately related factors are involved in getting food from farm to consumer, including the inputs, processes and outcomes of food systems, including nutrition and health. Food systems act as complex social-ecological systems, involving multiple interactions between human and natural components. Better understanding these drivers and how they interact to influence activities and outcomes of the food system, can help to improve public policies. Efforts to define, measure and model progress towards sustainability have led to the development of a variety of indicators and models that monitor and simulate (some of) these aspects of sustainability. In this chapter, we present an additional approach that consider vulnerability and resilience as the operating concepts to model the systemic factors that lead to final food systems' outcomes, such as food and nutrition security. properties of the food system that will ensure that its essential outcomes will be maintained or enhanced over time, across generations, can help organizations and governmental institutions track progress towards sustainability and set policies that will encourage positive transformations. The Latin Arc countries -Spain, France and

Italy -have been selected as the study area for the biophysical and socioeconomic common features of this transnational area.

The first section of the chapter reviews the background and theory of sustainability, recalling that assessment exercises aim at identifying fundamental systemic properties. We discuss in particular the concepts of vulnerability and resilience proposed in social-ecological system frameworks as key concepts for sustainability assessment. Building on dynamic system theory, we then suggest a formal representation of the overall food system to structure its different elements; clarify the distinctions between input, state and output variables; and formalize the scale at which systems' dynamics are operating. In the third section, we present a stepwise application of the model, identifying specific drivers and issues for the Latin Arc and formulating explicit interactions. We finally motivate this approach in the discussion section.

-Identifying the fundamental sustainability properties of the food system

Sustainability as a system property

The multidimensional nature of sustainable development -which has to satisfy several economic development, social equity, and environmental protection goals -is generally emphasized. Proponents of sustainable agriculture have for instance proposed alternative farming practices, which are less environmentally impacting but also embedded in new sets of values and carrying other visions of organization in society. These renewed approaches to agriculture -such as organic farming, lowinput agriculture, biodynamic agriculture, regenerative agriculture, permaculture, agroecology, etc. -are interesting crucial initiatives rooted in the ground. Yet, sustainability in agriculture cannot be defined per se by the simple adherence to one of these approaches; these are propositions of solutions towards sustainability.

The most frequently quoted definition of sustainability comes from Our Common Future, also known as the Brundtland Report (UN, 1987). Human development must meet "the needs of the present without compromising the ability of future generations to meet their own needs". This forward-looking imperative highlights the intergenerational and inter-temporal dimensions of sustainability, which thus infer that stewardship of both natural and human resources is of prime importance to ensure long-term development. When applied to the agricultural and food sector, Conway's frequently quoted definition of agro-ecosystem sustainability refers to "the ability of a system to maintain productivity in spite of a major disturbance, such as caused by intensive stress or a large perturbation" [START_REF] Conway | Agroecosystem analysis[END_REF]. [START_REF] Hansen | Is agricultural sustainability a useful concept?[END_REF] further interprets sustainability as a system's ability to continue over time. The concept of agricultural and food sustainability refers to a property of a system, rather than an approach to agriculture. Only such an understanding can offer a way out of the logical flaw of judging the sustainability of approaches that have been defined in the first place as sustainable, and help assess the contribution of these approaches towards sustainability.

Sustainability is a property of a system that is open to interactions with the external. It is the dynamic preservation, over time, of the intrinsic identity of the system among perpetual change (Gallopin, 2003). Multiple factors influence the course of humanenvironment interactions, which are further complicated by the presence of coevolving causal forces. Research in both the natural and social sciences uses the idea of a system to explain complex dynamics. A system is a network of multi variables that are connected to each other through causal relationships. Modern societies depend on complex systems to provide food [START_REF] Fraser | A framework for assessing the vulnerability of food systems to future shocks[END_REF]. Food systems encompass an array of activities from sowing through to waste disposal management, including production, processing, packaging and distributing, and retail and consumption [START_REF] Ingram | Food system concepts for the ESF/COST Forward Look on European food systems in a changing world[END_REF]. Furthermore, global environmental and socioeconomic changes are occurring concurrently, affecting food activities. Food systems, in turn, have an impact on the environment, as activities and outcomes are also drivers of global environmental change, engendering feedback loops and cross-scale interactions. If assessing sustainability is about understanding these dynamics to gauge the ability of a system to maintain or enhance essential outcomes, it requires viewing the system as a whole. System thinking can be a useful approach to capture causal loops, where the effects of the last element influence the input of the first element. The coupled Human-Environment System or the Social-Ecological System (SES) [START_REF] Holling | Cross-scale morphology, geometry, and dynamics of ecosystems[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]Ericksen, 2008c;[START_REF] Ostrom | A General Framework for Analyzing Sustainability of Social-Ecological Systems[END_REF] approaches allow moving away from looking at isolated events and their causes, and looking at systems made up of interacting parts. The analysis and the assessment of the sustainability of the food system are here conducted through the application of a SES framework.

A social-ecological framework

SES frameworks originate from ecosystem management and Ecology. SESs can be defined as complex human-nature adaptive systems linked by dynamic processes and reciprocal feedback mechanisms, with a substantial exchange of energy and materials across boundaries (Berkes et al., 2000;[START_REF] Folke | Resilience: The emergence of a perspective for social-ecological systems analyses[END_REF]. A crucial challenge towards sustainability of food systems is the management of dynamics originating from both global and internal changes, and their different synergistic impacts on systems' outcomes. Only a better understanding of these processes will help estimating and forecasting resulting tradeoffs between human wellbeing and ecosystem services, economic performances and environmental impacts. Vulnerability and resilience have emerged in recent years as one of the principal SES framing concepts for research on global change (Donning, 2000;O'Brien & Leichenko, 2000;[START_REF] Kates | Sustainability Science[END_REF]Schroeter et al., 2005;[START_REF] Polsky | Building comparable global change vulnerability assessments: The vulnerability scoping diagram[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF].

Vulnerability/resilience assessment and modeling are today acknowledged methods to explore sustainability of SES. There are several illustrations of approaches analyzing across food systems their vulnerability and resilience to global socioeconomic and biophysical changes in order to explore sustainability, highlighting key system processes and characteristics [START_REF] Ericksen | Global environmental change and food security[END_REF][START_REF] Darnhofer | Assessing a farm's sustainability: insights from resilience thinking[END_REF][START_REF] Allouche | The sustainability and resilience of global water and food systems: Political analysis of the interplay between security, resource scarcity, political systems and global trade[END_REF].

Vulnerability and resilience constitute different but overlapping research themes [START_REF] Turner | Vulnerability and resilience: coalescing or paralleling approaches for sustainability science?[END_REF]. Both address the consequences and the responses of system to social and/or environmental changes. Their continuing differences in approach to socialecological dimensions of change are still in discussion (Miller et al., 2010). For a comprehensive review, please consult [START_REF] Alwang | Vulnerability: a view from different disciplines[END_REF]. Ericksen (2008c) argues that the vulnerability approach "frames the consequences of environmental change for food systems in the context of socioeconomic and political change so as to understand the synergistic effects of the multiple stresses that interact with food systems, sometimes making these systems vulnerable" or not. The common ground of (almost) all approaches to vulnerability considers it as an "intrinsic characteristic of a system" at risk. The conditions and properties of the exposed system -or element of the system -are the crucial features to be identified and assessed [START_REF] Birkmann | Measuring vulnerability to promote disaster-resilient societies: Conceptual frameworks and definitions[END_REF]. In the meantime, vulnerability deals also with features linked to capacities of the system to anticipate and cope with the impact of a change or hazard [START_REF] Bohle | Vulnerability and criticality: perspectives from social geography[END_REF]. This allows flexibility in applying vulnerability for largely different elements, such as structures and physical characteristics of buildings, ecosystems and environmental functions and services, but also communities and social groups.

The concept of resilience, originating in Ecology, is central to visualizing the dynamics of the coupled system. Resilience is interpreted differently by SES scholars but commonly recognized as a multi-attribute concept, composed of: i) ability to cope with disturbance or change and retain control of function and structure; ii) capacity to self-organize; and iii) capacity to learn and adapt [START_REF] Walker | Resilience management in social-ecological systems: a working hypothesis for a participatory approach[END_REF][START_REF] Berkes | Navigating social-ecological systems: building resilience for complexity and change[END_REF][START_REF] Walker | Resilience, adaptability and transformability in social-ecological systems[END_REF]. Both vulnerability and resilience stress the need for methods and metrics that do not just express final results or outcomes, but provides a system of information that can be interpreted in a causal framework modeling interactions between different variables.

Building on [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF], the conceptualization of sustainability as the dynamic ability of a given system to maintain or enhance its essential outcomes over time, allows vulnerability and resilience theories to provide the elements to understand the mechanisms likely to affect activities within the system. The challenge for SES framework analysis here is to identify the pathways leading to vulnerability, and the characteristics and opportunities ensuring resilience of the food system in a context of change. Since contemporary food systems are characterized by cross-scale interactions and feedbacks across time and space and between the social and ecological components [START_REF] Cash | Scale and cross-scale dynamics: governance and information in a multilevel world[END_REF], efforts to rate how changes affect the performance of social, ecological and economic systems over time are key for the process towards sustainable development (Gallopin, 2003). At the same time, desired systemic properties can be expanded by investing specific components of systems (Marshke & Berkes, 2006). In particular, the vulnerability framework can be disaggregated in several dimensions according to different drivers of change:

vulnerability to climate change, vulnerability to price volatility, vulnerability to demographic transformations, etc.

Vulnerability/Resilience for the analysis of food system sustainability

Vulnerability in SES depends on the stress to which a system is exposed, its sensitivity, and its adaptive capacity and resilience opportunities. In line with the internationally recognized IPCC definition, De Lange et al. ( 2010) state that "Vulnerability is generally considered as a function of exposure to a stressor, effect

(also termed sensitivity or potential impact) and recovery potential (also termed resilience or adaptive capacity)". This is a clear and synthetic definition of vulnerability in its components that will be fundamental for the modeling exercise.

Exposure refers to the existence or presence of elements, in the system, that are susceptible to be adversely affected by the occurrence of environmental or sociopolitical stresses (IPCC, 2012). It is a necessary but not sufficient first condition for a

given system to experience stress or perturbations. Sensitivity is the degree to which a system is potentially affected by its exposure to a stress or perturbation [START_REF] Adger | Vulnerability[END_REF].

It can be understood as the potential magnitudes of consequences of being exposed [START_REF] Downing | Assessing socioeconomic vulnerability to famine: Frameworks, concepts, and applications[END_REF]. Indicators of sensitivity measure generally impacts. See Prosperi et al. (2014), or chapter 3, for further clarification.

Recovery potential is composed of adaptive capacities and resilience opportunities.

These are related to the potential of the system to respond to changes, including adaptation and transformation [START_REF] Ipcc | Climate change 2001: Impacts, adaptation, and vulnerability[END_REF][START_REF] Burton | From impacts assessment to adaptation priorities: the shaping of adaptation policy[END_REF][START_REF] Adger | Adaptation to climate change in the developing world[END_REF].

Adaptation captures the capacity of a system to learn and adjust to changing processes, and "continue developing within the current stability domain or basin of attraction" [START_REF] Berkes | Navigating social-ecological systems: building resilience for complexity and change[END_REF]cited in Folke et al., 2010). Systems will absorb disturbances and retain their original structures and processes. Transformation has been defined as "the capacity to create a fundamentally new system when ecological, economic, or social structures make the existing system untenable" [START_REF] Walker | Resilience, adaptability and transformability in social-ecological systems[END_REF]. Transformation is then necessary for the system to maintain its functionalities.

Resilience is more specifically concerned with the ability of a system to "absorb shocks, to avoid crossing a threshold into an alternate and possibly irreversible new state, and to regenerate after disturbance" (Resilience Alliance, 2010). The ability of a system and its component parts to anticipate, absorb, accommodate, or recover from the effects of a hazardous event in a timely and efficient manner, including through ensuring the preservation, restoration, or improvement of its essential basic structures and functions. Exposure refers to relational variables, i.e. elements that characterize the relationship between the system and its environment (Gallopin, 2006). It is the first point of contact between the stress or perturbation, and the system. Although commonly included in vulnerability [START_REF] Chambers | Editorial Introduction: Vulnerability, Coping and Policy[END_REF][START_REF] Adger | Social vulnerability to climate change and the architecture of entitlements[END_REF][START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Ipcc | Climate change 2001: Impacts, adaptation, and vulnerability[END_REF][START_REF] Polsky | Global Change Vulnerability[END_REF], exposure has recently been excluded from vulnerability in the last IPCC definition to actually align the understanding of vulnerability as a pure attribute of a system existing prior to and apart from the disturbance. In the earlier IPCC definitions, reference was indeed made as well to information on the change itself (e.g. its magnitude, rate of variation, duration, etc.), as well as on the presence of elements that are exposed. The question whether vulnerability is determined purely by the internal characteristics of a system, or whether it also depends on the likelihood that a system will encounter a particular hazard, is a long-standing dispute [START_REF] Brooks | Vulnerability, risk and adaptation: A conceptual framework[END_REF]. We will consider here the conventional framework for vulnerability. The understanding of exposure as the first interface with a specific driver of change helps differentiating it from the sensitivity or resilience components, which might be influenced by other drivers of change (Fussel, 2006).

When a food system fails to deliver food security or has the potential to do so in the face of a perturbation, the system can be considered to be vulnerable (Ericksen, 2008a). [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF] state that "The social-ecological system considers the human-environment interface as a coupled "system" where socio-economic and biophysical drivers of change interact to influence activities and outcomes, of the food system, that subsequently influence drivers of changes in a feedback loops dynamic".

Such systems can exhibit coherent behaviors. Constituting elements interact in a complex but lawful way. How can we account for the confluence of so many factors simultaneously? Resolving these issues is beyond the scope of traditional, linear, closed-system methods. Viewing food system sustainability from a dynamic systems perspective makes it possible to examine non-linear, complex, and reciprocally causal processes more explicitly. In the next section, we build on system thinking to identify the main variables to formalize and operationalize the abstract and multidimensional concept of sustainable food systems.

-Formalizing the food system as a dynamic system

What is a dynamic system?

The term "dynamic system" -or "dynamical system" -refers to a set of interacting elements that change over time. The first assumption of the dynamic approach is that evolving systems are complex, i.e. composed of many individual elements embedded

within, and open to, a complex environment. These elements function together as collective units, producing outputs in relation to inputs through processes endogenous to the system. Changes in one variable will impact all other variables of the system, with possible lagged and multi-scale effects. It can include natural as well as human components. Outcomes thus emerge from the complex interactions among system elements and are not just the product of external causes.

The field of dynamic systems is vast. From initial work in cybernetics [START_REF] Wiener | Cybernetics[END_REF][START_REF] Ashby | An introduction to cybernetics[END_REF] and system theory [START_REF] Kalman | Fundamental study of adaptive control systems[END_REF][START_REF] Bertalanffy | General system theory: Foundations, development, applications[END_REF], system thinking grows directly from advance in Mathematics and Physics. Psychology also uses system-based approaches to explore human behavioral patterns. The more technical term "dynamic system modeling" refers to a class of mathematical equations that describe time-based systems with particular properties. Systems can be classified in different ways. System models can be either continuous or discrete. They can be linear or nonlinear, and time-invariant or time-variant. Systems can be static if its output depends only on its present input. On the contrary, a dynamic system requires past input to determine the system output.

The approach begins with defining problems dynamically, proceeds through modeling stages, then builds confidence in the model and its policy implications. As highlighted in the previous section, the idea of change is key to sustainability. Sustainability is about maintaining and/or enhancing essential functions or outcomes over time, taking into account environmental, social, and economic constraints and assets. Food system sustainability can be viewed as the ex ante assessment of potential change in its functioning, given external conditions and internal dialectic. More precisely, sustainability approach and assessment aim at capturing (and protecting) the properties or features of the system crucial to supporting life, and food security in particular as the first reason for being of food systems [START_REF] Haddad | How should nutrition be positioned in the post-2015 agenda?[END_REF]. This requires examining how the multicausality of dynamic processes within complex system, such as the food system, could help understand changes over time towards food security.

A mathematical representation

Modeling dynamic systems is about representing mathematically the dynamics between the inputs and outputs of the system of interest. Figure 5 shows a simplified graphical representation of a dynamic system such as the food system. It captures a closed-loop system, with feedback from outputs to inputs. A "controller" can monitor the output of the system by adjusting control variables u to achieve a specified response. When modeling input-output systems, in addition to an observed set of variables internal to the system that can be levers of action, external drivers can enter the model as inputs [START_REF] Ionescu | Towards a formal framework of vulnerability to climate change[END_REF]. If considered exposed to external influences, the system is said to be non-autonomous [START_REF] Stankovski | Tackling the inverse problem for non-autonomous systems: application to the life sciences[END_REF]. A dynamical system can also be possibly perturbed by unobserved forces or noise. For the sake of simplicity, the presentation below is made under deterministic assumptions. For approaches motivated by stochastic models, see Aström (2012) and references therein.

Not all variables that appear in a model are of interest. The behaviors are usually captured by defining appropriate outputs. We choose outputs in order to describe those quantities that get focus. Food security can be considered as the principal outcome of food systems, if these systems are defined broadly and generically [START_REF] Haddad | How should nutrition be positioned in the post-2015 agenda?[END_REF][START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF][START_REF] Burlingame | Sustainable diets: the Mediterranean diet as an example[END_REF]. These outcomes are also determined by decisions and actions taken along the activities of the food system, but also by global socio-economic, political and environmental drivers through their impacts on the food system (Ingram et al., 2010). Such drivers might also impact food security directly. The state of the system at a given time, is the extra piece of information needed, so that given the input trajectory, it is possible to determine the behavior of the system over time. We call the state variables of the system. These variables provide the minimum amount of information that fully describes the system at any given time .

A mathematical description of the system in terms of a minimum set of variables , together with knowledge of those variables at an initial time and the system inputs for time , are deemed sufficient to predict the future system states and outputs for all time .

Output functions are commonly used to characterize the input-output relationships.

Dynamics of the system models are usually represented using differential or difference equations (with time as the independent variable). These equations, known as the transition functions, are formulated in state-space form that has a certain matrix structure.

The output equations are commonly written as 10 :

where is a vector function with n components for the n outputs of interest. All variables typically vary with time t.

Transition functions map the state of the model today into the state tomorrow. In vector notation, the set of differential equations may be written as:

where f is any vector function. The system state at any instant t may be interpreted as a point in an m-dimensional state-space 11 , and the dynamic state response can be interpreted as a trajectory traced out in the state-space [START_REF] Rowell | State-space representation of LTI systems[END_REF].

Another two equations (4.3 and 4.4) can be added to the usual differential equation to map the feedback to inputs [START_REF] Ionescu | Towards a formal framework of vulnerability to climate change[END_REF]. The problem of parameter estimation pertains to the identification of data and determination of numerical values of the elements of these matrices. 10 The notation below is a vector notation, which allows us to represent the system in a compact form.

11 With m variables determining the state of the system.

Categorizing variables, constructing a composite indicator

As explained in the second section, we are looking for the essential variables describing a system and the variables we can act upon to redirect food system toward looked upon objectives. In the language of dynamic systems, we are looking for x and u, the state and control variables. These are the essential features of the system that determine the trajectory of the system and characterize sustainability. A system can be understood by the response pattern following a perturbation. Perturbation reveals the nature of the system. To capture something of the internal dialectic of system, we suggest fixing some crucial external variables, or drivers of changes e, and seeing how these affect one of the system outcomes, i.e. our outcome of interest: food and nutrition security.

To highlight the internal dialect of food systems, we suggest using the concepts from the already existing vulnerability/resilience framework to clarify what we would like to proxy; literally, vulnerability is the propensity or predisposition of a socialecological system to be adversely affected by a change. Some global processes are significant drivers of change. There is high confidence that these include population growth, rapid and inappropriate urban development, international financial pressures, increases in socioeconomic inequalities, trends and failures in governance, etc.

Vulnerability describes a set of conditions of people that derive from the historical and prevailing cultural, social, environmental, political, and economic contexts As presented above, vulnerability/resilience is made up of three essential components:

Exposure, sensitivity and resilience. Thus, vulnerability V can be regarded as a function of the components recovery potential (RP) and potential impacts (PI), which in turn are expressed by exposure (E) and sensitivity (S).

The vulnerability/resilience framework can first help structuring the different elements, i.e. categorizing variables with regards to others, and thus constructing a composite indicator in the absence of statistical application able to reveal the structure of the data, though procedures such as Principal Component Analysis (PCA). See [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF] for a proposition of composite indicator. Second, the vulnerability/resilience framework allows articulating the different scales at which food systems are operating or embedded in. While defining system boundaries, attention should be paid to system level and spatial scale. The spatial scale at which the system is defined is crucial, as it will help identify the external variables affecting the system.

Figure 6 -A Sustainable food system framework (adapted from [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]Ericksen, 2008a;[START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF].

A map of the feedback structure of the system is a starting point. Building on the GECAFS food systems approach (Ericksen, 2008a,b;[START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF], coupled with Turner et al.'s (2003) conceptualization of vulnerability, we suggest the framework represented in Figure 6 to model food systems' dynamics. Dynamic systems consider mainly two types of variables: endogenous and exogenous variables. Endogenous variables are the elements that are interactive within the boundaries of the system of interest. In the case at hand, these variables are defined at the national or sub-national level. On the contrary, exogenous variables are factors that are not enclosed by the system boundary but influence the system. Exogenous variables are on the other hand not directly influenced by variables enclosed within the system. Outcomes from the food system activities may however contribute to these external drivers, but geographically specified food systems are assumed driver-takers 12 . In our specific case, these external drivers of change are at the broader regional level or global scale.

The three components of vulnerability -exposure, sensitivity and resilience -are the intrinsic features of the system that mediate the impact of the drivers of change on the food system's outcomes. These can be either state or control variables.

In this section, we specifically consider the large body of research on dynamic systems, and aim at applying this modeling approach to the assessment of food system sustainability. To assess the sustainability of the food system, we need to understand what might affect its processes, to which extent the drivers of change impact the food system's outcomes, and how actors respond to these pressures.

Answering the question that was first posed by

-Application: Addressing context-specific issues

A stepwise approach

Schroeter et al. ( 2005) developed an eight step methodological process to conduct vulnerability assessments. Following Schroeter et al. ( 2005), we propose a similarly structured and systematic method to apply the conceptual elements described in the above sections. These steps are preliminary to the identification of appropriate statistical variables, data application and scenario analysis. They involve proceeding in four stages:

1. Defining a study area and scale of analysis;

2. Identifying essential drivers of change;

3. Identifying essential food systems' outcomes;

4. Developing of a causal model by selecting essential interactions driver/outcome and examining respective systems' exposure, sensitivity and recovery potential.

Sustainability is usually conceived in place-specific terms. In the proposed framework, exposure to risks is dependent on the geographic context, and sensitivity and adaptive capacity are shaped by social and institutional factor elements [START_REF] Eakin | What is Vulnerable?[END_REF]. The first step includes choosing a scale of analysis and drawing artificial boundaries around the coupled human-environment system of interest. Every system incorporates some sub-systems, which are themselves based on components, which are in fact sub-systems, etc. Two points are crucial to consider when defining the system level and spatial scale of analysis: i) who are the intended users of the measurement set and ii) what is the degree of granularity of the food system's outcomes to be address.

This work is part of the project "Advancing through sustainable diets" that has a focus on France and Spain. Given that the assessment is targeting policy-makers as main users, we opted for analysis at the population scale rather than the individual scale. It has thus been decided that the final level of analysis will be national or subnational ("Comunidad autónoma" in Spain, "Région" in France and "Regione" in Italy). To draw the geographical boundaries, it has then been argued that the entities had to be subjected to similar type of food system concerns and exposed to similar type of drivers of change or factors of risk. Italy has thus been added to France and Spain as a possible study zone, on the ground that the three countries share similar food and nutrition security issues.

The northern coastal area of the western Mediterranean basin is commonly referred to as the "Latin Arc". It includes the coastal regions from Andalusia to Sicily. It is considered a homogeneous geographical entity closely related to certain summary representations of the European territory, at the regional level, proposed by geographers and urban scholars [START_REF] Camagni | Spatial Scenarios in a Global Perspective: Europe and the Latin Arc Countries[END_REF]Barrio, 2004;[START_REF] Daviet | Introduction. L'arc latin, histoire et problématiques d'un concept[END_REF][START_REF] Voiron-Caniccio | À la recherche d'un arc méditerranéen[END_REF][START_REF] Cortesi | Urban Change and the Environment: The Case of the North-Western Mediterranean[END_REF][START_REF] Vanolo | Innovation and Polycentrism in the Mediterranean Latin Arc[END_REF] As mentioned previously, the spatial scale at which the system is defined drives the identification of the external variables likely to affect the system. Sub-global/regional is a natural level for studies of SES. The Mediterranean basin has been identified as one of the most prominent "hotspots" in future climate change projections [START_REF] Giorgi | Climate change hot-spots[END_REF], but also in terms of environmental unsustainability due to intense human activity and agricultural exploitation [START_REF] Salvati | Toward a 'Sustainable'land degradation? Vulnerability degree and component balance in a rapidly changing environment[END_REF]. It has also been recognized as one of the first 25 Global Biodiversity hotspots in the world [START_REF] Myers | Biodiversity hotspots for conservation priorities[END_REF].

Identifying global and regional drivers of change affecting the food system outcomes

The second and third steps are crucial in applying the conceptual framework. It Water depletion:

Water depletion is "a use or removal of water from a water basin that renders it unavailable for further use" [START_REF] Molden | Accounting for water use and productivity[END_REF]. The Mediterranean region is greatly concerned by water stress and scarcity (FAO, 2011a;[START_REF] Parme | Quelles recherches et quels partenariats pour la Méditerranée?[END_REF]. The Western and Central Mediterranean areas are particularly subject to increasing water needs for domestic use, touristic and agricultural activities [START_REF] Sousa | Trends and extremes of drought indices throughout the 20th century in the Mediterranean[END_REF]. Water demand doubled in 50 years in Mediterranean countries (UNEP/Plan Bleu, 2006). The food system production and consumption patterns are increasingly water demanding.

Irrigated agriculture only accounts for 70% of the consumption of freshwater resources globally (OECD, 2013). In the EU-15, 85% of irrigated land is located in the Mediterranean area (France, Spain, Italy, Portugal, and Greece).

Water availability is closely related to climate change trends altering precipitation patterns and rainwater (Freibauer et al., 2011). Increase in the concentration of agrochemicals, soil nutrients, and a number of water pollutions are also observed, impacting the quality of water and further contributing to water scarcity [START_REF] Bates | Climate change and water[END_REF].

Biodiversity loss:

Biodiversity 13 loss is defined as "the long-term or permanent qualitative or quantitative reduction in components of biodiversity and their potential to provide goods and services, to be measured at global, regional and national levels" (CBD, 2004). Biodiversity is globally at risk, with 20930 species and ecological communities known to be threatened (IUCN, 2013). The Mediterranean region has been in particular catalogued as one of the 25 biodiversity hotspots of the planet with an exceptional diversity of endemic species within ecosystems that are at great risk, with 19% of the species threatened for extinction (IUCN, 2008).

Biodiversity loss is cogenerated by climate change, environment depletion and water stress. It is strongly related to modern food production and consumption patterns [START_REF] Altieri | Multifunctional dimensions of ecologically-based agriculture in Latin America[END_REF] that have become more intensive and homogenizing. The loss of agrobiodiversity is interlinked also with a number of causal factors, including habitat depletion, change in land use and management, GHG emissions, etc. [START_REF] Tilman | Agricultural sustainability and intensive production practices[END_REF][START_REF] Frison | Agricultural biodiversity is essential for a sustainable improvement in food and nutrition security[END_REF].

Food price volatility:

Food price volatility refers to large and atypical 14 "variations in agricultural prices over time" (FAO, 2011b). Food prices increased sharply in 2008, with the FAO food 13 Biodiversity is defined as the existence of species, genetic, and ecosystem diversity in an area [START_REF] Swingland | Biodiversity, definition of[END_REF]. 14 See FAO report Price Volatility in Food and Agricultural Markets: Policy Responses (Annex A, 2011) for a more technical definitions of price volatility.

price index breaking the threshold of 200 15 for the first time [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. The Mediterranean region is a particularly vulnerable region with regards to price volatility, in particular due to its cereal dependence, nutrition transition, population growth, urbanization and climate change effects [START_REF] Padilla | Dietary patterns and trends in consumption[END_REF].

Climate change impacts, changing trade patterns, new dietary trends and growing demand for biofuels are often invoked as among the causes of food price volatility.

The rising demand for food and fuel, originated from consumption and industrial purposes, is engendered by both population growth and changes in food consumption patterns [START_REF] Brown | From Feast to Famine: After Seven Good Years What Now for Commodity Producers in the Developing World[END_REF]. Furthermore speculation on commodity markets and reduction of food stocks are also crucial determinants of price variations [START_REF] Robles | When speculation matters[END_REF].

Changing food consumption patterns:

Changing food consumption 16 patterns refers to the changing structure of global food consumption, related to changing dominant values, attitude and behaviors [START_REF] Kearney | Food consumption trends and drivers[END_REF]. Globally, food consumption patterns are changing both in terms of total amount and composition. Worldwide consumers have switched from considering animal protein a luxury food item to considering it a regular part of the diet [START_REF] Meade | New International Evidence on Food Consumption Patterns[END_REF]. 15 Base 100: 1998-2000. 16 This social driver is proposed as one regime driver by the EU-SCAR 2nd Foresight exercise report (2009), closely linked to the other social global driver "changing dominant values", and is exactly phrased "Consumption quantities and patterns", referring to literally to "food consumption patterns" and "nutritional transition".

Identifying food and nutrition security issues

It is important at this point to formalize the hypotheses to be explored. The "what is vulnerable" is identified by the functions performed by the ecological and social service delivering entity composed of a number of actors, activities and processes.

The system will be considered vulnerable if negative food system outcomes emerge. Food, or more precisely feeding population, is agriculture and food systems' main reason for being [START_REF] Haddad | How should nutrition be positioned in the post-2015 agenda?[END_REF]. Human nutrition should be considered one of the most fundamental ecosystem services, or alternatively as dependent on several ecosystem services, including provisioning, regulating, supporting and cultural services [START_REF] Deckelbaum | Econutrition: Implementation models from the Millennium Villages Project in Africa[END_REF].

Food security, defined as the situation that exists when all people, at all times, have physical and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life (FAO, 1996), is a policy issue of importance in just about every country. It can be considered the principal outcome of food systems. It is also important to remember that food security is not just about the amount of food but also depends on the nutritional quality, safety and cultural appropriateness of foods [START_REF] Liverman | Food systems and the global environment: An overview[END_REF]. Investigating the influence of socio-economic and environmental drivers on food and nutrition security, with regards to some essential food system characteristics, can provide an approach to think the causal mechanisms that can lead to unsustainability. As mentioned above, four food and nutrition security issues have been identified as crucial for the Latin Arc countries.

Nutritional quality of the food supply:

The Nutritional quality of food supply refers to the nutritional composition of the food products on the market (Oquali, INRA/ANES). The improvement of the nutritional quality of the food supply is one of the eight specific actions defined by the WHO European Action Plan for Food and Nutrition Policy 2007-2012 17 . A balanced diet is 17 The WHO European Action Plan for Food and Nutrition Policy 2007-2012 defines eight specific actions for "ensuring a safe, healthy and sustainable food supply: improve the availability and affordability of fruit and vegetables; promote the reformulation of mainstream food products; promote appropriate micronutrient fortification of staple food items and develop complementary foods with adequate micronutrient content; improve the nutritional quality of the food supply and food safety in public institutions; ensure that the commercial provision of food products is aligned with food-based dietary guidelines; explore the use of economic tools (taxes, subsidies); establish targeted programmes for the protection of vulnerable and low socioeconomic groups;

achieved through personal habits but also requires that the foods on offer to consumers have a satisfactory nutritional composition. In France, a food quality observatory (Oqali) was set up to monitor the quality of the food supply. Increasing availability and consumption of nutrient-poor and energy-dense foods and beverages lead to enhancement of human health problems, including obesity and noncommunicable chronic disease.

Affordability of food:

According to [START_REF] Ingram | A food systems approach to researching food security and its interactions with global environmental change[END_REF], affordability of food is "the purchasing power of households or communities relative to the price of food". It refers to the "economic access" to food [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. Affordability is about food being available at prices that people can afford to pay, and in particular, whether low-income consumers can afford to buy enough nutritious food to meet basic needs [START_REF] Barling | The re-emergence of UK National Food Security on the policy agenda: sustainability challenges and the politics of food supply[END_REF].

The determinants of food affordability include pricing policies and mechanisms, seasonal and geographical variations in price, local prices relative to external prices, the form in which households are paid, income and wealth levels [START_REF] Ingram | Food system concepts for the ESF/COST Forward Look on European food systems in a changing world[END_REF].

Food affordability and food prices are important determinants of food choices [START_REF] Lee | Monitoring the price and affordability of foods and diets globally[END_REF].

Dietary energy balance:

Dietary energy balance refers to the balance between caloric intake and energy expenditure [START_REF] Patel | Effects of energy balance on cancer in genetically altered mice[END_REF]. Excessive fat accumulation is acknowledged to be a risk factor for various health problems, including CVD, diabetes, cancers and osteoarthritis (WHO, 2014). Obesity has become a significant public health in high and medium income countries, with 500 million adults obese worldwide and more than 1 billion projected by 2030 if no major effort is made (Kelly et al., 2008;[START_REF] Finucane | National, regional, and global trends in body-mass index since 1980: systematic analysis of health examination surveys and epidemiological studies with 960 country-years and 9•1 million participants[END_REF]. Body weight results from the integrated effects of food consumption, physical activity and genetics. A range of environmental, social and behavioral factors interact to determine energy intake and expenditure, such as sedentary lifestyles, heavy marketing of both energy-dense foods and fast food outlets, adverse social and economic conditions, the consumption of high-sugar drinks, etc. [START_REF] Swinburn | Diet, nutrition and the prevention of excess weight gain and obesity[END_REF].

establish intersectoral food safety systems with a farm-to-fork approach and in accordance with the Codex Alimentarius risk analysis framework."

Satisfaction of cultural food preferences:

Cultural food preferences are environmental factors related to social background, which contribute to food choices and intakes. It now acknowledged that honoring ethnic and cultural food preferences, compatible with nutritional requirements, is essential for food acceptance and wellbeing. Social and cultural norms have a crucial role in diet [START_REF] Sobal | A conceptual model of the food and nutrition system[END_REF]. Food preferences, socially or culturally determined, are now recognized as a key consideration in food security, as highlighted already in the 1996 definition of food security. Assessing cultural issues surrounding food preferences may also help improve dietary adherence to recommendations.

A causal model

The fourth step is about developing a causal model, formalizing into a model the dynamics of exposure, sensitivity and resilience. The four drivers of change and four food security issues, presented above, are matched to explore their possible causal relationships. The proposed framework aimed at identifying the food system characteristics that make the food system capable of sustaining food and nutrition security outcomes. This can serve to identify warning signals, although the drivers and outcomes of interest will have to be evaluated as well. Results are presented in Table 2.

Food and Nutrition Security Issues

Drivers of change

Nutritional quality of food supply

WATER DEPLETION

Potential Impact

• Contributing to decrease of production and productivity of sufficient and nutritious foods. • Engendering low dilution capacity and consequent contamination of agrofood products. • Impacting the availability of quality foods for poor consumers through higher cost of water. [START_REF] Bates | Climate change and water[END_REF][START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF][START_REF] Brown | From Feast to Famine: After Seven Good Years What Now for Commodity Producers in the Developing World[END_REF][START_REF] Ericksen | The value of a food system approach[END_REF][START_REF] Wood | Lessons learned from international assessments[END_REF][START_REF] Parme | Quelles recherches et quels partenariats pour la Méditerranée?[END_REF][START_REF] Dangour | Linking agriculture and health in low-and middle-income countries: an interdisciplinary research agenda[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF] Recovery potential

Affordability of food

Potential Impact

• Altering productivity, prices and trade, and then food availability and affordability. • Increasing water prices lead to higher costs of agrofood production and to decrease in food affordability. [START_REF] Ingram | Stakeholders' Approaches to Regional Food Security Research[END_REF][START_REF] Wood | Lessons learned from international assessments[END_REF][START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF] Recovery potential

Nutritional quality of food supply BIODIVERSITY LOSS

Potential Impact

• Shifting to ecologically simplified systems based on cereals contributes to poorly diversified diets. • Hampering food systems responses against climate change, with consequent impact on productivity. • Increasing the dependency on global varieties on external inputs. [START_REF] Randall | Diet diversity and nutrient intake[END_REF]Torheim et al., 2000;[START_REF] Pelletier | Changes in child survival are strongly associated with changes in malnutrition in developing countries[END_REF][START_REF] Frison | Agricultural biodiversity, nutrition, and health: Making a difference to hunger and nutrition in the developing world[END_REF][START_REF] Brunori | The Second SCAR Foresight Exercise, Synthesis Report 'New challenges for agricultural research: climate change, food security, rural development, agricultural knowledge systems[END_REF][START_REF] Roche | Traditional food diversity predicts dietary quality for the Awajun in the Peruvian Amazon[END_REF][START_REF] Arimond | Simple food group diversity indicators predict micronutrient adequacy of women's diets in 5 diverse, resource-poor settings[END_REF]Remans et al. 2011;[START_REF] Dangour | Linking agriculture and health in low-and middle-income countries: an interdisciplinary research agenda[END_REF][START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF][START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF] Recovery potential

• Promoting agrobiodiverse systems for ecosystem services, food security benefits (nutritional value of foods), the viability of agricultural systems and longterm productivity. • Fostering organic farming [START_REF] Thrupp | Linking agricultural biodiversity and food security: the valuable role of agrobiodiversity for sustainable agriculture[END_REF][START_REF] Reidsma | Regional farm diversity can reduce vulnerability of food production to climate change[END_REF][START_REF] Eakin | What is Vulnerable?[END_REF]

Satisfaction of cultural food preferences

Potential Impact

• Putting at risk cultural traditions and preferences, linked to regional varieties and diets. • Homogenizing food production.

• Contributing to reduce the enormous amount of information, on nutritional and health benefits of the foods that shape the food cultural preferences of people. • Decreasing food biodiversity could result in the loss of unique and traditional foods. [START_REF] Kuhnlein | Indigenous peoples' food systems: the many dimensions of culture, diversity and environment for nutrition and health[END_REF][START_REF] Kearney | Food consumption trends and drivers[END_REF][START_REF] Liverman | Food systems and the global environment: An overview[END_REF][START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF][START_REF] Jacques | Monocropping cultures into ruin: the loss of food varieties and cultural diversity[END_REF] Recovery potential

• Knowing how to prepare a more varied diet can influence consumption of different food products. • Providing more varied and tasteful diets.

• Enhancing and keeping traditional food cultures. [START_REF] Termote | Eating from the wild: Turumbu indigenous knowledge on noncultivated edible plants, Tshopo District, DRCongo[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF][START_REF] Khoury | Increasing homogeneity in global food supplies and the implications for food security[END_REF]

Potential Impact

• Impacting food production and consumption.

• Altering food supply towards disadvantaged groups.

• Leading to profound changes in the composition and availability of food supplies. • Hampering the present agrofood system supply, strongly interlinked with fossil fuels system. (DEFRA, 2008;[START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF][START_REF] Friel | Unequal Food Systems, Unhealthy Diets[END_REF]WHO, 2014) Recovery potential

• Enhancing dietary diversity for avoiding dependency on few groups of foods. • Fostering local provisioning and production, less involved in price variations. [START_REF] Herforth | Promotion Of Traditional African Vegetables In Kenya And Tanzania: A Case Study Of An Intervention Representing Emerging Imperatives in Global Nutrition[END_REF][START_REF] Pinstrup-Andersen | Nutrition-sensitive food systems: from rhetoric to action[END_REF]

Affordability of food

Potential Impact

• Impacting household incomes and purchasing power.

• Affecting agrofood productivity, and therefore food affordability and availability • Exacerbating economic shocks for the poor, who depend on wages and the rest of the economy. • Shifting purchasing strategies to lower quality products. [START_REF] Ingram | Food system concepts for the ESF/COST Forward Look on European food systems in a changing world[END_REF][START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]UK Cabinet Office, 2008;[START_REF] Wood | Lessons learned from international assessments[END_REF][START_REF] Hlpe | Price volatility and food security: a report by the High Level Panel of Experts on Food Security and Nutrition of the Committee on World Food Security[END_REF][START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF][START_REF] Lee | Monitoring the price and affordability of foods and diets globally[END_REF][START_REF] Meade | New International Evidence on Food Consumption Patterns[END_REF] Recovery potential

• Fostering food industry's focus on consumers and their need for "affordable food of high quality and diversity". • Shifting towards cheaper or locally available foods, meeting the same caloric and nutritional requirements. • Implement food policies for diversifying supply sources through different strategies (subsidies, food stamps). • Promoting diversity in food consumption patterns. (European Technology Platform, 2008;[START_REF] Brunori | Security for whom? Changing discourses on food in Europe in times of a global food crisis[END_REF][START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF] Nutritional quality of food supply

CHANGES IN FOOD CONSUMPTION PATTERNS

Potential Impact

• Influencing food industry production patterns, overall food security and nutritional characteristics of diets.

Dietary Energy Balance

Potential Impact

• Increasing consumption of fats, sugars, sweeteners, animal products, highly processed foods, and in fast foods and vending machines products. • Decreasing consumption in plant proteins and of homeprepared foods. • Strengthening "obesogenic" environments with little energy expenditure and sedentary lifestyles. • Altering frequency and the amounts consumed of foods.

• Decreasing dietary diversity. [START_REF] Swinburn | Dissecting obesogenic environments: the development and application of a framework for identifying and prioritizing environmental interventions for obesity[END_REF][START_REF] Unscn | Fourth Report on the World Nutrition Situation, United Nations System Standing Committee on Nutrition (SCN)[END_REF][START_REF] Popkin | The shift in stages of the nutrition transition in the developing world differs from past experiences![END_REF][START_REF] Nielsen | Changes in beverage intake between 1977 and 2001[END_REF][START_REF] Garrett | Stunted child-overweight mother pairs: Prevalence and association with economic development and urbanization[END_REF][START_REF] Ley | Microbial ecology: human gut microbes associated with obesity[END_REF][START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF][START_REF] Ericksen | The value of a food system approach[END_REF][START_REF] Friel | Unequal Food Systems, Unhealthy Diets[END_REF][START_REF] Liverman | Food systems and the global environment: An overview[END_REF][START_REF] Parme | Quelles recherches et quels partenariats pour la Méditerranée?[END_REF][START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF][START_REF] Lozupone | Diversity, stability and resilience of the human gut microbiota[END_REF]UNEP, 2012;[START_REF] Yatsunenko | Human gut microbiome viewed across age and geography[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF] Recovery potential

• Fostering public awareness for healthier diets through campaigns and community movements. • Enhancing cultural knowledge on preparing varied diets and on nutritional and health benefits of the foods. • Promoting weight loss and metabolic health through appropriate changes in the gut microbiota. • Supporting guidelines on dietary strategies to counteract overweight and obesity. [START_REF] Barling | The re-emergence of UK National Food Security on the policy agenda: sustainability challenges and the politics of food supply[END_REF][START_REF] Kuhnlein | Indigenous peoples' food systems: the many dimensions of culture, diversity and environment for nutrition and health[END_REF][START_REF] Obersteiner | Green food systems for 9 billion[END_REF][START_REF] Termote | Eating from the wild: Turumbu indigenous knowledge on noncultivated edible plants, Tshopo District, DRCongo[END_REF][START_REF] Cardoso | The effects of green tea consumption and resistance training on body composition and resting metabolic rate in overweight or obese women[END_REF][START_REF] Freeland-Graves | Position of the academy of nutrition and dietetics: total diet approach to healthy eating[END_REF][START_REF] Lopez-Legarrea | The influence of Mediterranean, carbohydrate and high protein diets on gut microbiota composition in the treatment of obesity and associated inflammatory state[END_REF] These sets of characteristics are indicating how changes in water, biodiversity, food prices and food consumption patterns are transmitted through the food system, including the sequencing of events and the scale of interactions; how the food system is sensitive to these changes; and the adaptive capacity of the food system. This could lead to subsequent work to identify thresholds of change and to model quantitatively the interactions among stressors, attributes, and outcomes, to improve the general understanding of food system sustainability; it more importantly offers the elements that need to be assessed, i.e. the attributes that indicators can be measuring.

4.5-Discussion

Why vulnerability and resilience to assess sustainability?

In this chapter, we propose to analyze and assess the sustainability of food systems using the concepts of vulnerability and resilience. First, vulnerability is not the simple flip side of resilience. Following [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF], we argue that articulating the two -overlapping -concepts provides a more comprehensive framework to capture the features of complex systems, such as food systems, perpetually evolving and reorganizing into unexpected new configurations. The identification of the elements within the system, and assessment of their sensitivity to change, in addition to the capacity of the system to cope, adapt and transform to these changes, are considered key to understanding dynamic systems. Resilience and vulnerability are relatively new, but now fundamental concepts in the contemporary language of sustainability sciences. The links between vulnerability and sustainability have been discussed

against the backdrop of a long-standing dispute about the relations between sustainability and resilience. Resilience is commonly accepted as at least a crucial dimension of sustainability. Some argue that resilience of a system constitutes a necessary but not sufficient condition for sustainability [START_REF] Derissen | The relationship between resilience and sustainability of ecological-economic systems[END_REF]. How do the concepts of vulnerability and resilience square with the definition of sustainability?

Sustainability is a normative concept that provides a broad framework to guide actions; it requires defining specific goals and their monitoring measures that need to be agreed and acknowledged by all stakeholders [START_REF] Anderies | Robustness of Social-Ecological Systems: Implications for Public Policy[END_REF]. The design of legitimate and collective decision processes is crucial to sustainability. On the contrary, resilience and vulnerability as descriptive concepts characterize the dynamic properties of a system, and can thus help define these societal goals. Sustainability and vulnerability/resilience can thus be understood as distinct concepts operating at different levels, the latter concepts providing the elements to inform the decision process intrinsic to the former concept.

Although the concepts of "vulnerability" and "resilience" have entered the food policy discourse, the influence of SES thinking on policy-maker agendas has otherwise been rather limited [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. SES frameworks emphasize complexity and systemic interactions. Applications of these frameworks tend thus to focus on problem identification and improving system understanding [START_REF] Nadasdy | Adaptive co-management and the gospel of resilience[END_REF]. As mentioned earlier, food systems are systems of variables connected to each other through causal pathways, which are further complexified by operating at different geographical or time scales. Vulnerability and resilience can be useful approaches to capture these relationships. One key conceptual element of vulnerability/resilience models is a clear distinction between causal events and outcomes [START_REF] Dilley | Coming to terms with vulnerability: a critique of the food security definition[END_REF]; it frames a "causal factor approach" that describes the interactions leading to the final outcomes. Exposure, sensitivity and resilience provide the concepts to identify the system's properties that shape causal pathways towards food system's outcomes.

Systems behave in a circular organization forming feedback loops. The proposed fragmentation in specific vulnerabilities and resilience factors -through the intersections of different drivers and issues -can induce a certain degree of linearity in causality. Vulnerability and resilience answer questions about mechanisms that operate to produce outcomes under certain specific conditions. As such, it provides policy-makers with a model of highly formalized predictions of the effects of a limited set of variables [START_REF] Epstein | Missing ecology: integrating ecological perspectives with the social-ecological system framework[END_REF], which can be tested recursively and provide insights into possible feedback. Modelers are generally faced with the dilemma of how comprehensive a model to build: "one with many variables that ends up as a qualitative description, or one with a few key variables that acts quantitatively but lacks comprehensiveness" [START_REF] Fraser | A framework for assessing the vulnerability of food systems to future shocks[END_REF]. It has also to be recalled that sustainability as a forward-looking concept requires apprehending the conditions and determinants to maintain systems' functions over time. By focusing on a number of external forces and highlighting systemic internal dialectic, the vulnerability/resilience model allows a dynamic analysis of some specific issues of the food systems and provides direction for policy-makers.

Why these specific issues and drivers?

Building on Schroeter et al. ( 2005), two of the four sub-steps proposed to resolve the complexity that arise when integrating social and ecological approaches, imply specifying food systems' outcomes and external drivers.

It is, therefore, required first to clarify the principal outcomes or functions of a food system, in particular the issues at risk. Food systems serve several purposes and have several outcomes. What are the priority issues? Outcomes might be evaluated and ranked differently by different stakeholders, and at different levels. The proponents of the "Sustainable Diet" agenda highlight the food and nutrition security objectives of the food systems selected here as the end-point of the analysis (FAO & Bioversity, 2012). As mentioned above, following a review and after discussion in two focus groups, four food and nutrition security concerns have been retained judged crucial to the context at hand. However, other issues have been debated, such as "food safety" or "dietary quality". Other food systems' outcomes than food and nutrition security issues could also have been considered, such as environmental and socio-economic outcomes related to employment or equity. Food systems are responsible for diverse environmental, economic and social outcomes. Introducing these would have been maybe more in line with the general perception of what sustainability means. The articulation between food systems' defining elements and their resulting outcomes, the former contributing to predict the latter, could be expanded to other dimensions to further the modelling approach. Sustainability can hardly be modeled parsimoniously, raising then questions in terms of feasibility of the modeling.

The second step is to understand what and how global or regional changes, either socio-economic or environmental, might be transmitted through the activities to impact the outcomes, because food systems' complexity means that impacts may not always be felt directly. Experts invited to the focus groups mentioned other important drivers of change, such as "climate change" or "technological innovation". They also wondered if the model captures completely the internal drivers that are intrinsic to the system. Drivers are interacting with each other. Climate change and biodiversity loss are closely related for instance, with reciprocal influence. This interdependence raises some technical modeling concerns, named variables acting as possible proxy for other variables it is associated with. We thus aimed, as much as possible, to select priority drivers, excluding two drivers that are directly linked. Some analytical clarity and direction are indeed essential to convince policy-makers and have any policy impact.

It is moreover desired to develop interventions that treat the underlying causes, rather than the symptoms of the unsustainability deriving from food systems. The concepts of vulnerability and resilience bring food security into consideration in a different way than in the past. Changes are happening and investigating the sources of adaptive capacity in the system is crucial. This approach also highlights that food security is a matter both for the North and for the South, although with different modes of expression, and cannot be dealt with only by looking at national concerns [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

-Conclusions

Developing policy to ensure sustainable food security is a tremendous challenge that requires a comprehensive and integrated analytical approach. Multiple factors influence the course of human-environment interactions, which are further complicated by the presence of co-evolving causal forces. Understanding these dynamics requires viewing the food system as a whole. Social-ecological system approaches allow moving away from looking at isolated events and their causes and start to look at systems made up of interacting parts. Vulnerability and resilience is suggested in this chapter as a possible approach to capture the food system as a whole, think prospectively and identify the system elements that policy can leverage.

The distinction in three components, namely exposure, sensitivity and resilience, provides the elements of a model that specify what attributes need to be measured and how to structure the different indicators in a coherent framework for improved decision-making and policies.

The concept of vulnerability and of resilience imposes a system thinking approach based on the interdependencies between drivers, system activities and properties, outcomes and feedback loops. Vulnerability and resilience of food systems can have multiple sources, and these sources may interact to generate unexpected responses [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. As sustainability and food security becomes increasingly central, vulnerability/resilience will be among the principles that will drive the reformulation of research, as well as policies [START_REF] Brunori | Security for whom? Changing discourses on food in Europe in times of a global food crisis[END_REF]. Concepts and methods for global change, vulnerability/resilience assessments represent a new research frontier.

More theoretical and empirical research is needed to measure and assess the interplay between human and environment systems, between causal factors and consequences.

Appropriate tools have to be developed for monitoring, forecasting and integration in policy support measures.

Chapter 5

Using Delphi expert elicitation survey to define indicators for assessing the Sustainability of the Food Systems

-Introduction

The scientific and international debate on sustainability of diets and food systems is gaining increasing recognition in the international community (FAO & Bioversity International, 2012). Interconnected environmental sustainability and food and nutrition security topics, and the debate about strengthening the links between food, health, and environmental research, are gaining increasing intensity [START_REF] Scar | 3rd SCAR foresight exercise: Sustainable Food Consumption and Production in a Resource-Constrained World[END_REF].

However clear consensus on metrics of sustainable diets and food systems is still lacking and a host of efforts are being implemented towards this goal [START_REF] Fanzo | Metrics of sustainable diets and food systems[END_REF][START_REF] Vinceti | The contribution of forests and trees to sustainable diets[END_REF]. Understanding what needs to constitute the assessment of the sustainability of food systems and diets is key for providing decision-and policymaking with knowledge of action, and having a systemic rationale and a framework to build a metric system is indispensible [START_REF] Fanzo | Strengthening the engagement of food and health systems to improve nutrition security: Synthesis and overview of approaches to address malnutrition[END_REF]. It is then necessary to investigate the impact of the determinants on the sustainability of diets and identify the appropriate tradeoffs related with recommendations and actions towards the sustainability of the food systems [START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF].

The coexistence of undernutrition, nutrient deficiencies, overweight and obesity -the tripe burden of malnutrition (Pinstrup- [START_REF] Pinstrup-Andersen | Agricultural research and policy to achieve nutrition goals[END_REF] -is inviting us to reconsider health and nutrition as the primary goal of food systems. Moreover, while improving food and nutrition security, agriculture and food industry have generated unintended consequences including environmental losses (UNEP, 2012;[START_REF] Allen | Agricultural biodiversity, social-ecological systems and sustainable diets[END_REF].

Simultaneously, several regions are experiencing unprecedented weather events caused by climate change and habitat depletion, in turn further destabilizing global food and nutrition security [START_REF] Thompson | The impact of climate change and bioenergy on nutrition[END_REF][START_REF] Dora | Indicators linking health and sustainability in the post-2015 development agenda[END_REF]. This confluence of food crises with increasing environmental degradation suggests an urgent need for novel analyses and new paradigms to describe and understand the causes and facilitate adaptation and mitigation.

Participants at the 2010 international conference organized by the FAO and Bioversity International agreed on a common definition of Sustainable Diets that emphasizes the food and nutrition security purpose of food systems, and the need to maintain or enhance this outcome over time -across generations -by preserving essential human assets and the flows of services they provide (FAO & Bioversity International, 2012). The concept of Sustainable Diets promotes economically, socially and environmentally sustainable food systems that concurrently ensure food and nutrition security [START_REF] Fanzo | Metrics of sustainable diets and food systems[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF].

Modern societies depend on complex agro-ecological and trading systems to provide food. The move to sustainable diets calls for changes in the agricultural and food systems. Policy-makers and other stakeholders need evidence-based information and assessment tools to lead public policy interventions [START_REF] Barrett | Measuring Food Insecurity[END_REF]. Sustainability in general provides decision makers with development strategies to allow present and future generations meeting their needs within the limits of the earth's capacity. Thus, it is a concept that offers a perspective of the dynamics that regulate the interconnection within social and ecological systems [START_REF] Carpenter | Resilience: accounting for the noncomputable[END_REF]Rockstrom et al., 2009;[START_REF] Waas | Sustainable development: A bird's eye view[END_REF]. The sustainability of diets and food systems needs to be explored and assessed to provide decision-makers with information on socioeconomic and biophysical determinants and outcomes that regulate the system dynamics over time. In order to translate sustainability from a concept to a tangible strategy, indicators are key tools. Sustainability indicators can represent a set of metrics that measure characteristics or mechanisms that regulate the socio-ecological systems and ensure its continuity and functionality over time [START_REF] Benitez-Capistros | Environmental impacts on the Galapagos Islands: Identification of interactions, perceptions and steps ahead[END_REF].

Metrics are an organized system combined to provide a perspective and have three principal objectives: inform civil society, industry, public officials and all stakeholders; measuring progress towards defined goals; aid decision making processes (UN, 2007). Indicators are variables that offer information on other variables that are limited [START_REF] Gras | Le fait technique en agronomie[END_REF]. They synthetize the information [START_REF] Andersen | An indicator-based method for quantifying farm multifunctionality[END_REF][START_REF] Girardin | Indicators: tools to evaluate the environmental impacts of farming systems[END_REF][START_REF] Mitchell | PICABUE: a methodological framework for the development of indicators of sustainable development[END_REF][START_REF] Rigby | Constructing a farm level indicator of sustainable agricultural practice[END_REF][START_REF] Singh | An overview of sustainability assessment methodologies[END_REF] and provide benchmarks for decision-making [START_REF] Gras | Le fait technique en agronomie[END_REF][START_REF] Thivierge | Environmental sustainability indicators for cash-crop farms in Quebec, Canada: A participatory approach[END_REF]. Indicators are variables that can simplify a complex message and are developed to transfer information to decision makers [START_REF] Bell | Sustainability indicators: measuring the immeasurable?[END_REF].

Indicators of sustainable development at the national level are often identified through dynamic interactive and participatory approaches with stakeholders such as government representatives, technical experts, and civil society agents. A sound theoretical framework is the starting point in constructing metrics (OECD, 2008). Sustainability -or Sustainable Development -is a necessarily complex concept that can have different understandings. For our purpose, we assume that a sustainability assessment aims at capturing the ability of a system to maintain and enhance its essential functions over time [START_REF] Conway | Agroecosystem analysis[END_REF][START_REF] Hansen | Is agricultural sustainability a useful concept?[END_REF].

Sustainability addresses threats to preserving life support systems, including their capacity to withstand and adjust [START_REF] Turner | Vulnerability and resilience: coalescing or paralleling approaches for sustainability science?[END_REF]. It is then key to assess stocks of and changes in human and natural assets (Stiglitz et al., 2009). Derived from sustainability sciences, the vulnerability approach, complemented by inputs from the resilience literature (see [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF], is proposed to analyze the sustainability of critical food and nutrition security outcomes (see chapter 4 and Ericksen, 2008c;[START_REF] Eakin | What is Vulnerable?[END_REF][START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF].

Vulnerability -as the degree to which a system is likely to experience harm due to exposure to a perturbation or stress -is a function of exposure, sensitivity, and resilience. Exposure is the nature and degree to which a system is likely to be affected by the occurrence of a change. Sensitivity is the degree to which a system is affected either adversely or beneficially, by a change. Resilience is the ability of a system to anticipate, absorb, accommodate, or recover from the effects of a potentially hazardous event in a timely and efficient manner, through ensuring the preservation, restoration, or improvement of its essential basic structures and functions [START_REF] Ipcc | Managing the risks of extreme events and disasters to advance climate change adaptation: Special report of the intergovernmental panel on climate change[END_REF].

Several global and regional drivers of change affect the structure and processes of the food systems [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF] putting at risk context-specific food and nutrition security outcomes (Ericksen, 2008a). Based on an extensive literature review, four critical food and nutrition security issues and fours drivers of change have been identified. An indicator-based approach is then proposed to assess the sustainability of diets and food systems, through a vulnerability and resilience framework. These Several decision support tools have been identified and applied for providing guidance to decision makers for solving problems in social-ecological systems and global change contexts, yet several approaches fail to be validated. Therefore, it is usually recommended to use expert elicitation to offer solutions for decision-making [START_REF] De França Doria | Using expert elicitation to define successful adaptation to climate change[END_REF]. The Delphi method represents a support tool for decision-making that implies the participation of a broad range of different experts, can be applied on a global scale, is based on anonymous responses, and can generate interactions between experts having different opinions and coming from different geographical backgrounds [START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF]. The Delphi method is a popular social research technique for forecasting and an aid in decision-making, and its aim is to obtain a reliable common opinion from a group of individual experts who can each provide anonymous valuable contributions in order to resolve a complex problem on the basis of free opinions and knowledge, avoiding influences from personality and authority [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF][START_REF] Linstone | The Delphi method: Techniques and applications[END_REF].

Aims

The main goal of this research study is to identify a set of metrics of sustainable diets and food systems. The vulnerability and resilience framework was used as an analytical lens to provide a sequential list of sustainability indicators, while the Delphi method was used to determine which indicators are perceived as more relevant according to a selected group of participants. Delphi is an iterative questionnaire designed to elicit expert's knowledge. The study also investigated whether crucial information and further aspects related to food system sustainability were lacking in the structure proposed, which elements and interlinkages could be added and in which manner.

The system-oriented approach that is proposed, for the assessment of sustainable diets and food systems, incorporates elements from the vulnerability and resilience theories. The Turner et al.'s (2003) vulnerability/sustainability framework is one of the most quoted integrated conceptual models for vulnerability assessment [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF]. Exposure, sensitivity and resilience provide the concepts to identify the system's properties that shape a causal pathway towards food system's outcomes, and these are the variables that we aim to proxy through the Delphi expert elicitation process (see chapter 4).

There is one crucial question the panel of experts were asked to answer:

Vulnerability/resilience of what to what? Four main food and nutrition security issues -i.e. food system outcomes at risk specific to the Spanish, French and Italian context -and four global and regional drivers of change -relevant to the Mediterranean region and likely to impact the identified issues -were identified. Three questionnaires, over three iterative rounds, were used and included the proposed indicators of exposure, sensitivity and resilience of four context-specific food and nutrition security issues, against fours drivers of change affecting the food system.

Following the protocol of the Delphi Survey, participants were asked to discuss and complement the framework and underlying assumptions, and test the framework by selecting proxy indicators. Succeeding rounds were designed to bring the group to focus or consensus. The second section of this chapter describes the Delphi approach adopted in this study, the participants, and the process undertaken. The third section describes the main findings of the study including consensus on indicators, drivers, issues, and on the vulnerability and resilience interactions proposed. The forth section reviews the usefulness and limitations of this study with respect to the results obtained and the methodology applied. We conclude that the Delphi-variant used in this study was useful in providing a clear and transparent means of exploring the complexities of the assessment of sustainable diets and food systems, and consensus was reached for a number of dimensions. Specifically, this study highlighted the challenges and the interest for further researches, through combining expert elicitation processes and a dynamic and analytical vulnerability and resilience framework, to generate a common working language and a set of metrics supporting decision-making for sustainable diets and food systems.

-Research design: Materials and methods

The Delphi technique is defined as "a method of structuring a group communication process so that the process is effective in allowing a group of individuals as a whole to deal with a complex problem" [START_REF] Hugé | Sustainability indicators for clean development mechanism projects in Vietnam[END_REF]. It is a procedure for organizing dispersed expert group debate to find answers to complex problems [START_REF] Linstone | The Delphi method: Techniques and applications[END_REF]. Within several valuable expert elicitation tools, the Delphi approach proved helpful for involving experts in an iterative process of problem definition and analysis, in order to attain unbiased views and estimations on different complex issues [START_REF] De França Doria | Using expert elicitation to define successful adaptation to climate change[END_REF], and convert these opinions into one or more communal notion/s through a feedback process [START_REF] Benitez-Capistros | Environmental impacts on the Galapagos Islands: Identification of interactions, perceptions and steps ahead[END_REF]. The Delphi technique is mostly applied by medical and engineering sciences, as well as in social sciences, and especially in different research domains and purposes spanning from medicine and public health [START_REF] Hwang | A time scale-oriented approach for building medical expert systems[END_REF][START_REF] Boulkedid | Using and reporting the Delphi method for selecting healthcare quality indicators: a systematic review[END_REF], to agrofood systems policy and food safety issues [START_REF] Wentholt | The views of key stakeholders on an evolving food risk governance framework: results from a Delphi study[END_REF][START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF], food security [START_REF] Wolfe | Building household food-security measurement tools from the ground up[END_REF], development and selection of indicators of sustainability [START_REF] Benitez-Capistros | Environmental impacts on the Galapagos Islands: Identification of interactions, perceptions and steps ahead[END_REF], definition of agrienvironmental indicators to assess sustainability [START_REF] Bélanger | Development of agri-environmental indicators to assess dairy farm sustainability in Quebec, Eastern Canada[END_REF] and sustainable aquaculture (Fezzardi et al., 2013 -FAO), topics related to agro-based bioenergy [START_REF] Rikkonen | Future prospects of alternative agro-based bioenergy use in Finland-constructing scenarios with quantitative and qualitative Delphi data[END_REF], meat consumption [START_REF] Vinnari | Future images of meat consumption in 2030[END_REF], educational research [START_REF] Green | The Delphi Technique in Educational Research[END_REF], farm sustainability [START_REF] Etxeberria | Development of sustainability reports for farming operations in the Basque Country using the Delphi method[END_REF], sustainability indicators for tourism [START_REF] Choi | Sustainability indicators for managing community tourism[END_REF] and related weighting [START_REF] Tsaur | Evaluating ecotourism sustainability from the integrated perspective of resource, community and tourism[END_REF], environmental, scientific and policy evaluations and scenarios [START_REF] Nowack | Review of Delphi-based scenario studies: quality and design considerations[END_REF][START_REF] Swor | Promoting environmental sustainability via an expert elicitation process[END_REF][START_REF] Wright | Giving "teeth" to an environmental policy: a Delphi study at Dalhousie University[END_REF], climate change impacts and vulnerabilities [START_REF] Mastrandrea | Probabilistic integrated assessment of" dangerous" climate change[END_REF][START_REF] Webster | Uncertainty analysis of climate change and policy response[END_REF]Arnell et al., 2005;[START_REF] Prato | Conceptual framework for assessment and management of ecosystem impacts of climate change[END_REF], adaptation to climate change and adaptive management [START_REF] Plummer | Charting the new territory of adaptive comanagement: a Delphi study[END_REF]de Franca Doria et al., 2009), landscape and conservation management [START_REF] Mehnen | The Delphi Method as a Useful Tool to Study Governance and Protected Areas?[END_REF], and vulnerability assessment [START_REF] De Lange | Ecological vulnerability in risk assessment-a review and perspectives[END_REF].

Generally a Delphi survey starts with an initial structured questionnaire -addressed to experts or participants -that leads to multiple interactions (rounds) between group members (expert panel) and the facilitator through a controlled feedback process.

Once completed the questionnaires each expert is provided with a common feedback on the group responses. Often the facilitator indicates, individually to each participant, his/her position within the global feedback of the panel. Provided with this information, the participants complete the survey form again. Then he/she can confirm or amend his opinion on the basis of the information proposed -in the global feedback -by the other participants. Thus, in each round the participants are in some way asked to judge the opinions and elements that were suggested by the group on the preceding round. The process can be reiterated several times in as many different rounds until consensus emerges or is achieved. Usually consensus is reached following two to four rounds. However, a larger number of rounds often generates an important decline in the participation [START_REF] Keeney | A critical review of the Delphi technique as a research methodology for nursing[END_REF].

Facilitators, in order to efficiently manage a Delphi study, have to consider that this iterative process can lead to large questionnaires with long lists of issues and information, that are time consuming to analyze, difficult to manage, and can further complicate consensus [START_REF] Hasson | Research guidelines for the Delphi survey technique[END_REF][START_REF] De França Doria | Using expert elicitation to define successful adaptation to climate change[END_REF][START_REF] Benitez-Capistros | Environmental impacts on the Galapagos Islands: Identification of interactions, perceptions and steps ahead[END_REF].

Building blocks of any Delphi process are participants' anonymity [START_REF] Landeta | People consultation to construct the future: a Delphi application[END_REF], a rigorous management of group through coalescing opinions and answering expert questions [START_REF] Dalal | ExpertLens: A system for eliciting opinions from a large pool of non-collocated experts with diverse knowledge[END_REF], and letting participants the possibility to amend their opinions. In particular anonymity, together with sufficiently extended time frames between rounds, contributes to avoid bias problems typical of group dynamics and allows experts freely presenting their judgments on the topics [START_REF] De França Doria | Using expert elicitation to define successful adaptation to climate change[END_REF].

In the present study, the Delphi method was conducted in an online environment, through emails sending and the web-based survey tool SurveyMonkey, an online survey creator (see www.surveymonkey.com). The online-based Delphi was adopted to improve the ergonomics of the process, avoiding unhandiness of paper-based surveys and easiness limitations as observed on other Delphi studies [START_REF] Cam | The Delphi method online: Medical expert consensus via the Internet[END_REF][START_REF] Steyaert | Participatory methods toolkit-A practitioner's manual[END_REF].

This Delphi study was conducted mainly focusing consensus around a list of indicators of sustainable diets and food systems over three iterative rounds. Experts

were also asked with a number of open and appraisal questions with regards to the contents (drivers of change and issues of food and nutrition security) that compose the framework, in order to confirm or not the importance of the food system dynamics that were proposed to study, and to further open the analysis to other key aspects related to the sustainability of the food system. Before starting the Delphi process the framework, the indicators, the selection of participants, the survey, and the structure of the study were discussed in two exploratory focus groups (see figure 7).

Participation and Panel composition

Selection of participants to a Delphi survey is critical. An expert is a person who is particularly competent as authority on a certain matter of facts [START_REF] Flick | An introduction to qualitative research[END_REF].

Identifying who is an expert -his/her expertise and knowledge -is challenging [START_REF] Burgman | Expert status and performance[END_REF][START_REF] Failing | Integrating science and local knowledge in environmental risk management: a decision-focused approach[END_REF], and selection must be performed thoroughly so that the group composition shapes the diversity of valuable knowledge [START_REF] Okoli | The Delphi method as a research tool: an example, design considerations and applications[END_REF][START_REF] Steyaert | Participatory methods toolkit-A practitioner's manual[END_REF]. For the purpose of this research we considered an expert as a person who, by a verifiable mean (particular scientific role, expertise/knowledge, publications), is known to have information or has access to information with regards to the issues under investigation. In this study, we opted for a two-stage sampling procedure.

In a first step, potential participants were selected by reviewing academic publications and participation to scientific conferences using broad keywords, and through professional networks. The sampling procedure identified experts working or doing scientific research on issues related to the sustainability of the food systems.

Then we classified experts as a group of informed individuals, specialists in a field, or those with expertise about specific topics (see [START_REF] Keeney | A critical review of the Delphi technique as a research methodology for nursing[END_REF]. The group included experts from a multiplicity of disciplines, to guarantee a heterogeneous array of opinions. 213 suitable candidates were finally listed. Information on academic discipline, age and sex was collected. Potential participants were invited to participate by e-mail and then telephoned. Co-nomination was authorized when one of the experts declined (generally due to lack of availability) and suggested a colleague instead. In a second step, background variables (academic discipline, age and sex)

were checked, and reminders and personalized emails were sent to individuals belonging to under-represented groups.

A first reminder was sent a week before the deadline for the first round and a second one four days later. On the last day, 41 questionnaires had been filled in. Therefore 18 experts were then contacted by telephone or, if not possible, sent another personalized email to balance the sample. An extra week was given to complete the questionnaire.

At the end of this process 51 experts returned the questionnaire. For the second round two reminders were sent, and a few identified experts were further emailed to maintain a balanced panel. For the third round two reminders were also sent and a few experts were further emailed. The data were collected between March 2014 and July 2014.

Preparation and distribution of Delphi questionnaires

First, an electronic letter of invitation to the Delphi expert consultation was sent to the potential participants. The invitation (see Annex 1) enlightened the goals and methods of the study, and permitted potential participants to self estimate their expertise and aptness to the study [START_REF] Dalkey | The Delphi Method, IV: Effect of Percentile Feedback and Feed-In of Relevant Facts[END_REF]. Two weeks later, a nonpersonalized email was sent to all identified experts with the link to the questionnaire and reading material. This material, distributed to all potential participants, comprehended a document explaining the conceptual background, the specific aim and purpose of the Delphi study (see Annex 2), and the indicator list (see Annex 3).

Then, for each of the three consecutive rounds, electronic letters were sent to invite participants to fill in the questionnaire.

The online questionnaire was first created in an MS Excel (XLS) environment and then directly uploaded to SurveyMonkey (see Annex 4). The obtained data was kept and could be downloaded in an XLS format for statistical and text analysis. Reports describing the results of each questionnaire were sent via email after each of the three Delphi rounds, separately to each participant. In the attached PDF file with the results, for each participant his/her individual choice was highlighted.

The time frame asked to respond to each of the three consecutive rounds was of two weeks. However, as predicted, reminders were needed to send to let the maximum rate of participant respond. Extra time was necessary for some experts to fill in the questionnaires, therefore the actual time frame that participants were given has been of three weeks for the first round, and four weeks for the second and third rounds.

After the first and the second rounds an additional time frame of eighteen days was required for completing the analysis of data and for providing participants with a modified questionnaire. Overall, the time elapsed between the delivery of the first and the third questionnaires, was approximately 3 months. The final results were given four months and ten days after sending the first letter of invitation to the Delphi expert consultation.

The Vulnerability and Resilience framework

This Delphi process is based on an integration of concepts and scientific approaches to study the broad topic of the sustainability of diets and food systems -including social-ecological systems frameworks, and theories and assessment of vulnerability and resilience -with the aim of identifying a set of metrics for improving decisionmaking. The vulnerability and resilience framework was applied building on the interactions between drivers of change and food and nutrition security issuesfollowing the vulnerability framework proposed by [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF] see also chapter 4) -and disentangling these interactions in exposure, sensitivity and resilience. The vulnerability and resilience framework was chosen because of its proven suitability for drawing linkages between socioeconomic and biophysical causal factors within a given system, for its usefulness in multidisciplinary perspectives, and because it fills in science and policy gaps [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF].

Also, indicators represent one approach to making theoretical concepts, such as vulnerability and resilience, operational. Using available scientific knowledge in form of frameworks, theories or models about the vulnerable system of interest in the selection of indicating variables, and considering literature and expert judgment, relate to what Hinkel (2011) defines "using deductive arguments" and "theory-driven approaches" in the development of vulnerability indicators.

Following the methodological guidelines of the vulnerability assessment (Schroeter et al., 2005) it has been possible to identify a geographical area of interest (the west Mediterranean Europe countries, France, Italy and Spain), four drivers of change impacting the food system and four units of the food system likely to be vulnerable to changes (food and nutrition security issues); a set of interactions between these two categories (of drivers and issues) were identified (see chapter 4). The drivers of change selected were adapted from the drivers proposed by the second report of the European Union Standing Committee on Agricultural Research ( 2008) at the European level, such as water depletion, biodiversity loss, food price volatility, and changes in food consumption patterns. The vulnerable context-specific units of the food system were identified within the general food and nutrition security issues (availability, access, utilization) -as main outcomes of a food system -following the main understanding brought by the definition of food and nutrition security (UN, 1996) and the framework of the food system in the context of global change (Ericksen, 2008a;Ingram et al., 2010), such as nutritional quality of food supply, food affordability, dietary energy balance, and satisfaction of cultural food preferences. The interactions -between drivers and issues -were identified on the basis of the structure of the vulnerability framework [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF], and related indicators were identified through an extensive and context-specific literature review (see Annexes 2 and 3).

Building on the mentioned vulnerability and resilience framework, the base structure for identifying the indicators was a matrix framework displaying the interactions between the "impacting" drivers of change and the "affected" food and nutrition security issues, within a complex interconnected food system (see Annex 2). The indicators were organized -for each vulnerability interaction -in the three components of vulnerability, such as: exposure, sensitivity, and resilience (see Prosperi et al., 2014 and chapter 4). The indicators were proposed for each of these three components following previous approaches to vulnerability assessment (Fussel & Klein, 2006;Schroeter et al., 2005). As mentioned above, the suggested framework and the initial shortlist of indicators were developed in discussions with selected experts in two focus groups. In fact, it is strongly recommended for Delphi process to gather an exploratory workshop to refine round one Delphi. The objective is ensuring the best, most comprehensive, and most focused issues for involving participation in a quantitative survey and overcoming possible limitations of international participation. Furthermore, the experts participating in the focus groups can facilitate the implication of researchers or other experts, within their contacts, for participating in the Delphi process (cascade methodology) [START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF].

Six experts participated in the focus groups, as senior researchers from multiple disciplinary backgrounds closely related to the sustainability of the food system, including also a specialist of the Delphi method. The meetings with the reduced panel in the focus groups consisted of a presentation of the proposed framework and discussion on the main issues and drivers considered, and on the criteria for reducing the pools of indicators. The goal of these focus groups was to test the questionnaire and to anticipate the likely perception of the large panel of experts. The focus groups meant also to represent a sample for exploring the practical applications in the large survey panel of experts. In the present study, the selection criteria for identifying the indicators were mainly related to keywords for drivers of change and issues, and to the mechanisms and interactions of the food system functioning. These criteria were explained to the experts in the focus groups. The exploratory focus groups allowed improve the ergonomics of the online survey, reduce and ameliorate the list of indicators provided, enlarge the contacts of potential participants to invite, and verify that the food system issues under discussion were particularly relevant.

Data analysis

In each round participants were asked to select the best indicator within each of the 24 components presented (i.e. [exposure + sensitivity + resilience] times 8 interactions).

Indicators that not received any participant preference were excluded from the framework. New indicators were added if at least two participants proposed the same, or similar, proxy variables to enter in a specific component (only indicators proposed by at least 2 participants were reported -Indicators were considered as close enough when at least 2 words in the title or details of the indicators were common or judged similar [eg. "Number of crops", "variety of crops" and "crop concentration"]). The questionnaire implied also questions on the appraisal of the framework, other than the selection of the indicators. Thus, participants were asked to judge the importance of the drivers of change and the proposed interactions, and to rank by importance the issues of food and nutrition security through a Likert scale. It was also asked (not compulsorily) to propose further drivers and issues.

The data analysis of each round was based on descriptive statistics that were returned to experts through an iterative process. For the selection of indicators -in the three rounds -the results were indicated in percentages. For the close-ended questionssuch as, Not at all important / Not that important / Important / Very Important -on the appraisal of drivers and interactions, the results were indicated in percentages of rating. With regards to the appraisal of the food and nutrition security issues, a Likert scale was used for the evaluation of a 9-point (with 1 being the lowest and 9 being the highest). Except for the indicator selection, the appraisal of the elements of the framework was conducted through single assessments that were not reiterated in the Delphi process. In the argumentative section, qualitative comments were categorized and reported in each feedback. Higher priority was placed in addressing comments raised by a higher proportion of experts, and in those that were associated with higher disagreements. The purpose of this procedure was to minimize biases attributable to the facilitator during the process.

-Results

The Delphi sample characteristics

Usually Delphi studies involve on average between 15 and 60 experts, and within this range a Delphi panel is generally considered valid [START_REF] Hasson | Research guidelines for the Delphi survey technique[END_REF]. In this Delphi study 51 experts, corresponding to 24% of the all experts who were invited, returned the questionnaire of the first round. However this actually indicates a response rate of 72% of those who acknowledged receiving the invitation (see Table 3). Comparable decreases of participation were observed in other Delphi studies [START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF][START_REF] Wentholt | The views of key stakeholders on an evolving food risk governance framework: results from a Delphi study[END_REF]. Nonetheless, the number of experts is not always considered key. It is rather required a balanced composition of the panel and an adequate quality level of participants [START_REF] Powell | The Delphi technique: myths and realities[END_REF]. Strong variations of the panel through the Delphi process or disequilibria might lead facilitators to stop the study earlier than expected [START_REF] Benitez-Capistros | Environmental impacts on the Galapagos Islands: Identification of interactions, perceptions and steps ahead[END_REF].

With regards to the experts who replied to the first round questionnaire, 66% were males and 34% were females. The majority (33%) are economists -although from different sub-disciplines ranging from agricultural and food economics to resources and environmental economics -closely followed by nutritionists (22%). Agronomists and environmental scientists represent 10% and 8% respectively, and food technologists 4%. About 12% of the panel can be associated to sustainability science(s) and another 8% as working specifically on food policy and governance. We focused on agrofood economists and nutritionists, as they are the main groups who have published in the area of sustainable diets and food systems.

In the round two -given the relatively small samples in Delphi surveys -achieving and maintaining a certain degree of participation was crucial to ensure the validity of the study. Overall, 39 experts (out of 51) logged in again and answered to the second round of the questionnaire, i.e. a response rate of 76.5%, above the highest threshold (70%) encountered in the literature [START_REF] Akins | Stability of response characteristics of a Delphi panel: application of bootstrap data expansion[END_REF]. Two reminders were sent, and a few identified experts were further emailed to maintain a balanced panel. Women represent about one third of the sample (31%). Economists and nutritionists remain within limits (36% and 28% respectively). System agronomists and sustainability scientists represent 10% each, and ecologists and food policy/governance specialists 8%. Only 1 panelist brings in food technology expertise.

In the round three -36 experts (out of 39 of the second round) responded to this third and last round of the survey, i.e. a response rate of 92%. As for previous rounds, two reminders were sent and a few experts were further emailed to maintain a balanced panel. Final participation indicates that women represent about one third of the sample (31%). Economists and nutritionists are still the best represented (33% and 22% respectively). Agronomists and ecologists represent about 8.5% of the panel each, and declared sustainability scientists 5.5%. Participants suggested two new groups: statisticians (5.5%) and food system specialists (3%). One panelist brings in explicitly food technology expertise. Confirmation about the scientific field of the experts was asked only in the last round, to avoid overload the previous rounds. Still the answers confirmed the heterogeneity level of the panel over the Delphi process that was maintained through constant monitoring of the multidisciplinary composition (see Table 4).

Progression of consensus on the indicators

Delphi round 1

In this initial step of the survey it is normal to observe largely distributed inputs for indicator preferences. Majority (≥50%) is reached only for 4 indicators and dimensions, while in 12 dimensions we observe one or more indicators reaching 35% and in 8 dimensions all indicators are still below 35%. 4 initial indicators were not selected and were then excluded from the list for the round 2. On the other hand 14 new indicators were proposed by participants and, therefore, introduced for selection in round 2. A descriptive analysis of the results of this stage is still not appropriate for indicators.

Delphi round 2

Consensus is clearly emerging for 10 of the 24 desired indicators (i.e. more than 60% of agreement on one indicator); however no indicator has yet met the defined high threshold consensus criteria (80%). For some interactions and components, panelists seem to be balancing between two main options (7 components, out of 24, present two indicators displaying more than 30% agreement each). 31 indicators, that were proposed in the round 2, were not selected and were then excluded from the list for the round 3. Experts suggested 4 new indicators that were integrated to the questionnaire for selection in round 3.

Delphi round 3: final results

Consensus is finally reached for 14 of the 24 desired indicators: 8 indicators have met the high threshold consensus criteria (80%), 3 other indicators have met the medium threshold consensus criteria (70%) and other 3 ones have achieved the low threshold consensus criteria (60%). 4 indicators have been selected by the majority of the participants (above 50%). These values that define the different rates of consensus criteria were proposed by [START_REF] Keeney | A Classical Delphi Design Case Study[END_REF] and are largely acknowledged in Delphi studies. Furthermore, according to [START_REF] Hasson | Research guidelines for the Delphi survey technique[END_REF] and de Franca Doria et al. (2009), it is also suggested that consensus between 51% and 80% should be considered acceptable.

For 5 dimensions (out of 24), clear bipolarity can be reported (two indicators above 35%). In some of these cases, several experts have recommended constructing a composite indicator. 3 dimensions remain unresolved with a wide dispersion of expert opinions among indicators and little improvement of the consensus through the rounds. Furthermore, "Don't know" rates (the default option) are high only for these 3 dimensions. 23 proposed indicators were not selected in this round by any of the participants. Globally 56 (4 + 31 + 24) indicators were -in the first, second and third rounds -completely rejected by the panel by a rate of respectively 3%, 21% and 20% over the total indicators proposed in each round.

On average, 93% of the experts who selected the favorite indicator per dimension (at least 50%) in the second round confirmed their choices in the third round. Although there is no specific statistical test to measure the stability of responses between rounds for qualitative nominal variables, this observation indicates that a certain degree of stability of the consensus has been achieved.

Furthermore, 75% (18 out of 24) of dimensions reached, at least, a majority consensus (≥50%) on one indicator, and in all these cases the indicator which was the most chosen in the round 3, was been also the most chosen in the round 1 and in the round 2 (see Table 5). This additional observation contributes also to demonstrate a certain degree of stability of consensus. The progression of consensus is thus ascending over the three rounds (see Figure 9).

Figure 9 -Share of consensus (expressed in %) of the most selected indicator for each of the 24 vulnerability components considered (exposure, sensitivity, resilience) within each interaction over the three rounds (in ascending order of consensus)

Table 5 -Consensus rate (%) of the most selected indicator/s per vulnerability component in the three Delphi rounds

Appraisal of Interactions, Drivers, and Issues

Drivers

Four drivers of change were included in the initial framework, such as Water Depletion, Biodiversity Loss, Food Price Volatility and Changes in Food Consumption Patterns (see Chapter 4). In the first round experts were asked to propose other drivers likely to affect each of the suggested food and nutrition security issues. 65% of the panel made 139 propositions. 25% of them proposed drivers that already emanate from the framework and 75% were original suggestions. Each driver was classified according to the 2nd EU-SCAR Foresight Exercise's typology of drivers likely to significantly impact food systems' prospects [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF].

We were able to associate most of the participants' propositions with a shortlist of 12 broad drivers of change: Agrifood patterns (including industry and market structure) As regards additional potential drivers affecting affordability of food, two main drivers were suggested: Policies (30%) and Agrifood patterns (24%). Energy prices and Global economy trends were proposed by 11% and 8% respectively of respondents.

As regards additional potential drivers affecting dietary energy balance, Policies stands out as a main driver to consider (43%). World population (29%) and Agrifood patterns (14%) would come second. Changing dominant values and diversity in lifestyles -included in the global Changing food consumption patterns driver -have been frequently repeated.

As regards additional potential drivers affecting the satisfaction of cultural food preferences, Policies (36%), Agrifood patterns (27%) and World population (18%) are the most added drivers.

In order to prepare the questionnaire for the second round, the proposed drivers were added to the initial set.

Interactions

In the second round experts were asked to rank the importance of the eight initial interactions (between a driver of change and a food and nutrition security issue). All the eight proposed interactions have been judged "important" or "very important" by more than 80% of the panelists. Agreement on importance ranges from 85% (impact of biodiversity loss on nutritional quality of food supply) to 97% (impact of changing food consumption patterns on dietary energy balance) (Figure 10). In the second round, the two first proposed drivers, per issue, were submitted to the participants for ranking according to importance.

Overall, the newly proposed drivers have not reached the same high degree of consensus on importance for food and nutrition security as the initial set. Mainly three have attained comparable levels for some issues (near or above 80%), namely:

Changing agrofood patterns, Policy actions and Technological innovations (See figure 11). In particular, population dynamics appear not to be considered a priority concern for food and nutrition security.

It has to be reported that Climate change, proposed by 5% of the respondents in the first round, has been highlighted again in the open ended questions as an important driver to consider per se, in addition to Water depletion and Biodiversity loss.

Food and nutrition security issues

In the second round participants were invited to propose new food and nutrition security issues judged important for the geographical context considered (Spain, France and Italy), in addition to the four food and nutrition security context-specific issues proposed in the framework. 18 experts (45%) answered to this non-compulsory question and respondents suggested 5 additional issues. Two of these (environmental externalities and social equity) are not generally considered as conventional food and nutrition security issues, as usually encountered in the literature [START_REF] Pangaribowo | Food and nutrition security indicators: a review[END_REF]. Discussions should now focus on whether these two issues would actually fall within the sustainable food and nutrition security realm.

Accessibility has been suggested as another food and nutrition security issue by 3 participants, "next to affordability". An expert specified that "physical access" was a particular concern to consider. Another stated that "allocation of food within society/household" is an issue when discussing accessibility. Food safety was another issue mentioned. One expert mentioned "food system sovereignty and governance (transparency in decision-making, ability of consumers and producers to influence food system drivers and outcomes)". Other panelists talked about "food production patterns" and "re-orientation of industry [organization] or technological improvement" along the value chains. Several experts added "environmental impacts"

or "externalities". Others specifically mentioned "greenhouse gas emissions" or "biodiversity" or "water use" or "energy consumption", as food and nutrition security

issues. An expert highlighted the importance of "increased inequality in wealth/income distribution", while others added "inequitable (and unethical) healthy food distribution" or "equity" as food system outcomes that need to be considered.

Another expert mentioned labor regulations and corporate social responsibility as crucial elements for the future of the food systems.

The propositions of the experts have then been analyzed and categorized in five additional issues, namely: (Physical) accessibility, food safety, governance, environmental externalities and equity.

Participants were then asked to rate the priority of these nine issues using a scale of 1 to 9 (with 1 being the lowest and 9 being the highest) (see figure 12). The four initial issues appear within the first five priority challenges for food and nutrition security identified in the region. "Nutritional quality (of food supply)" is ranked the most important current issue (5.8). Two new challenges -"Environmental externalities"

and "social equity" -come second and third (5.6 and 5.3 respectively). As already highlighted, these two crucial questions are not conventional food and nutrition security issues, as usually encountered in the literature [START_REF] Pangaribowo | Food and nutrition security indicators: a review[END_REF].

"Satisfaction of cultural food preferences" (5.2) is judged the fourth most important issue, closely followed by "affordability of food" and "dietary energy balance" ex-aequo (5). The other three proposed issues fall below the median value of the scale (i.e. 5).

Figure 12 -Expert appraisal of the initial set of food and nutrition security issues and of the newly proposed ones (Likert scale 1 -9)

-Discussion

Discussion of the results

Discussion in terms of participation

The size of the expert group can vary depending on the complexity of the study and the management of the process. Generally the minimum number of participants required should imply at least four people [START_REF] Thangaratinam | The Delphi technique[END_REF], and there is not a maximum threshold, within the ability to ensure a sound and efficient management of the Delphi process. This is not only for the number of participants, (61%) effectively participated in the first round, and it was also specified that this number corresponded to 85% of those who initially accepted to participate (27). A third example of a Delphi study -on the identification of emerging food risk in the current food safety systems (Wentholt et al., 2012) -involved the invitation of 1931 experts, of whom only about 500 (22%) participated in the first round. Generally, as previously mentioned, a panel size within the range of 15-60 experts is considered appropriate for the application of the Delphi method [START_REF] Hasson | Research guidelines for the Delphi survey technique[END_REF]. In this Delphi study, the results obtained for the participation, both in absolute and percentage terms, largely fall within the standard recommendations for the implementation of the Delphi technique.

However, if on the one hand the number of experts is not always deemed fundamental, on the other hand balancing the panel may be considered compulsory and the validity of the Delphi study may be evaluated also on the basis of the quality of the experts [START_REF] Powell | The Delphi technique: myths and realities[END_REF]. Often Delphi specialists recommend facilitators to end the process if the panel balance and quality are not sufficiently accurate [START_REF] Benitez-Capistros | Environmental impacts on the Galapagos Islands: Identification of interactions, perceptions and steps ahead[END_REF]. In this Delphi study the multidisciplinary composition of the Delphi panel was accurately monitored over the progression of the three rounds. In fact the rate of participation of each disciplinary group was maintained constant from the first round to the third one. The standard deviation -observed for the variations of the participation within each disciplinary group over the three rounds -ranges from a minimum degree of 0.004 for food technologist to a maximum degree of 0.016 for food system specialists. With regards to economists and nutritionists, both the most represented disciplinary groups, their rate of participation over the global panel participation proceeds constantly (see Table 6). Furthermore, the comparative analysis of the disciplinary composition rate -between the panel of the first round and the initial group of invited experts -shows that both economists and nutritionists increased their relative rate of participation. This might suggest that these groups are strongly interested in, and sensitive to, the general topic proposed in this "Metrics of Sustainable Diets and Food Systems" initiative. Also, as previously mentioned, both economists and nutritionists appear to tackle -in numerous scientific publications -the relevant issues related to sustainable diets and food systems through an holistic and multidimensional approach [START_REF] Gussow | Dietary guidelines for sustainability[END_REF][START_REF] Wilkins | Eating right here: Moving from consumer to food citizen[END_REF][START_REF] Burlingame | Sustainable diets: the Mediterranean diet as an example[END_REF][START_REF] Guyomard | Eating patterns and food systems: critical knowledge requirements for policy design and implementation[END_REF][START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF][START_REF] Macdiarmid | Sustainable diets for the future: can we contribute to reducing greenhouse gas emissions by eating a healthy diet?[END_REF][START_REF] Esnouf | Food System Sustainability: Insights from DuALIne[END_REF][START_REF] Vieux | High nutritional quality is not associated with low greenhouse gas emissions in self-selected diets of French adults[END_REF][START_REF] Burlingame | Grand Challenges in Nutrition and Environmental Sustainability[END_REF][START_REF] Masset | Identifying sustainable foods: the relationship between environmental impact, nutritional quality, and prices of foods representative of the French diet[END_REF]. This was the main reason why they were mostly invited in the Delphi panel. Differently, the group of specialists in Ecology and Environmental resources, that was the second most invited category with nutritionists, may appear to be less sensitive to this initiative. In fact, from the starting point of the Delphi process, the results of the participation rate of this group has fallen largely below the attrition rate observed for the other groups. Although many of the experts invited from this group had long experience and considerable competence in vulnerability and resilience approaches and analysis of social-ecological systems framework, it is possible to suppose that some of them did not perceived to have common scientific interests and competences with a potential "Sustainable Diets" community.

However first it is necessary to consider that this sample, for its size, implies limitations of statistical analysis and then the details on participation rate progression may not be representative. Second, the Ecology and Environmental resources' group is composed by several subgroups of scholars working on various fields related to ecology research and natural resources management, and this avoids strong generalizations about the reasons of their results of participation rate. Third, in Delphi studies it is key to take into account the role of the scientific network and contacts (cascade approach) for balancing the heterogeneity of the panel. Despite the multidisciplinary aim of this study, the availability of professional contacts has not likely been exempted from the risk of bias because of the specific scientific environment and the background in which the initiative actually raised. Thereforesimilarly as in several Delphi studies [START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF] -the panel composition is mainly turned towards two groups (in our case economists and nutritionists) who bring important orientations and multidisciplinary diet-focused approaches. However, the involvement of several disciplines is key for further understanding and developing of systemic conceptual frameworks and assessment methods. Further analyses on participation rate by disciplines may rather belong to social, behavioral and cognitive science, and are not the main objective of this study.

Discussion on the indicators

According to [START_REF] Hasson | Research guidelines for the Delphi survey technique[END_REF] and de Franca Doria et al. (2009) consensus between 51% and 80% should be considered acceptable. Thus, in this Delphi studyas described in the results section -acceptable consensus on indicators was obtained on 18 interactions out of 24, which means an acceptable consensus on 75% of cases.

Consensus on different indicators has been also categorized according to the threshold proposed by [START_REF] Keeney | A Classical Delphi Design Case Study[END_REF], namely majority (x > 50%), low (x > 50%), medium (x > 70%) and high (x > 80%) consensus. This shows that the Delphi technique is usually adapted and modified depending on research contexts and goals.

In 6 interactions (25%) an acceptable consensus on one indicator was not reached, and in particular on 3 interactions a clear bipolarity was reported (two indicators above 35%). With regards to the dimensions where consensus on a single indicator was not achieved, it is still possible to find constructive elements for discussion. In fact, although the main goal of the indicators section is to identify a common consensus on one indicator, the Delphi technique still represents an opportunity to identify innovative solutions for unraveled problems. For some of the interactions that presented a manifest bipolarity of consensus, a number of experts proposed to integrate the two indicators into a composite one. This proposition could be potentially extended to all the interactions that presented bipolarity within the conceptual possibility of aggregation.

In Delphi studies stability of results is an essential criteria to assess the accuracy of the process. The main purpose of this study was to go through consensus for indicators that are qualitative nominal values, and there is no specific statistical test to measure the stability of responses between this kind of variables. Hence stability can be assessed through a descriptive statistical analysis that allow observing that, on average, 93% of the experts who selected the favorite indicator per dimension (at least 50%) in the second round confirmed their choices in the third round. This observation indicates that a certain degree of stability of the consensus has been achieved.

Furthermore, as mentioned above 75% (18 out of 24) of dimensions reached, at least, a majority consensus (≥50%) on one indicator, and in all these cases the indicator which was the most chosen in the round 3, was been also the most chosen in the round 1 and in the round 2. This additional observation contributes also to demonstrate a certain degree of stability of consensus.

With respect to the selection of the indicators proposed to the experts, it is possible to identify one hypothesis behind each indicator. These hypotheses lie on the causal mechanism of the vulnerability and resilience framework proposed. Thus, within a given interaction and belonging to one of the components of vulnerability (exposure, sensitivity, resilience) the hypothesis behind each indicator is formulated through the description of a functional relationship between indicator and vulnerability, as in a causal model similarly proposed by [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF]. In table 7 these hypotheses are formulated for the indicators that reached low, medium and high consensus from the panel of experts in the third round, and presented within the related interactions, and with descriptions and details. Even if an indicator list was provided, including a precise definition for each indicator and details about unit and bibliographical references, the hypotheses for each indicator were not integrated in the materials provided to the experts. The inclusion of this information in the indicator list would probably have helped participants for further understanding the framework and the selection process based on this causal model. However this would have also implied overloading participants with material to examine (it is reminded that experts were asked to make 24 choices within a list of 136 indicators) and it is acknowledged that an excessive burden of information exposes a Delphi process to loss of participation and to the risk of early termination [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF]. Also focus groups' experts warned about this risk and advised to keep a limited amount of information to provide to participants. desirable to be measured. For instance, in table 7, the indicator "% of diets locally produced" (CIHEAM & FAO, 2012) -interaction BL/SCFP -reached a medium consensus (72%) as proxy variable for the sensitivity of the satisfaction of cultural food preference in a condition of biodiversity loss. The hypothesis supporting this indicator states that the higher the share of diets that are locally produced, the higher will be the vulnerability level. This hypothesis is based on the fact that in case of high level of diets that are produced locally, the fulfillment of the food preferences (strongly dependent on this local production) will likely be more impacted by an erosion of biodiversity in the agrofood system, since the performance of the local production may be closely related to the good conditions (high biodiversity) of the local agrofood system. Experts expressed a medium consensus on this indicator instead of choosing one of the other indicators proposed in the sensitivity component of the same interaction (see Appendices 3).

Within these less-selected indicators some of them are quite easy to be measured. For instance the "Mediterranean Adequacy Index" [START_REF] Alberti-Fidanza | Dietary studies on two rural italian population groups of the Seven Countries Study 3. Trend Of food and nutrient intake from 1960 to 1991[END_REF][START_REF] Bach-Faig | The Mediterranean diet in Spain: adherence trends during the past two decades using the Mediterranean Adequacy Index[END_REF] or the "Consumer interest in ethical imports" (DEFRA, 2008) are two indicators that can be measured and are also widely acknowledged and well conceptually structured. Probably these two indicators were not favored since they are not enough appropriate for the specific interaction in which they have been proposed.

However this option can also be interpreted as a call for assessing factors that have not yet been measured, and for which there are still not available data. Hence it emerges one more reason for including or not, in the indicator list, further details on data availability; experts have been let choose freely for indicators without being influenced by the related availability of data. Is this the way "the best argument should win?"? Are panelists making "some tacit knowledge explicit?" According to Tapio et al.'s (2003) ideal outcomes for a traditional Delphi, these are two essential questions that a Delphi study can help to answer.

Discussion on the drivers of change

The drivers of change proposed in the framework (Water Depletion, Biodiversity

Loss, Food Price Volatility, Changes in Food Consumption Patterns) were not described -as well as the food and nutrition security issues -in the concept note of the technical brief that was provided to the experts. Drivers and issues were in fact considered enough widely acknowledged and understandable, also considering the level and the academic background of the experts invited. Moreover, during the exploratory focus groups it was suggested not to make the concept note overly heavy (namely "no more than 2 pages") to avoid attrition of participation. Finally, there

were not critical remarks on the general meaning of these drivers and issues from the experts who participated in the three Delphi rounds.

Relating to the appraisal of the drivers proposed, importance of biodiversity loss reached a weaker consensus among panelists; however it was the driver the most often ranked as "very important" as to its impact on the nutritional quality of food supply. While some experts considered that "changes in environmental resources will likely have impacts on nutritional quality of the food supply, (...) the primary driver of nutritional quality is not environmental. There is a substantial 'buffer' in the system that is associated with cultural/political/economic factors (...), for example, how food is processed and how the nutritional content of food is determined". There seems to be a certain opposition between panelists on the importance of biodiversity.

Discussion on the interactions

As mentioned in the results section, the categorization of drivers -likely to significantly impact food systems -presented in the 2nd EU-SCAR Foresight Exercise (2008) was used to group the drivers added by participants, through the analysis of the text.

Experts proposed a number of driver/issue interactions and the two most quoted per dimension were submitted for ranking importance. Hence, it was given the opportunity to propose new interactions, above those provided by the framework.

This exercise is part of the goal of a Delphi study; it represents the possibility for the group to create a common understanding on wicked problems [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF]. Once that the most quoted interactions have been identified and ranked by importance, they constitute eight additional typologies of impact of specific changes on the outcomes of the food systems. Also, they can represent eight more research hypotheses to explore the sustainability problems of the food systems. These newly emerged interactions are already acknowledged and established, at different extent and in different geographical contexts. The meaning of these interactions can be analyzed by providing general definitions of the interplay mechanisms.

Policy-actions constitute a driver of change that has been proposed by experts for impacting the affordability of food, the dietary energy balance, and the satisfaction of cultural food preferences. These interactions were mainly considered important by the Delphi panel. In this context, policy-actions comprehend the development and the implementation of governance tools and measures aiming at regulating the future growth of the food system through cross-sectoral gains including nutrition, health, trade, agriculture etc. With regards to the impact of policy actions on the affordability of food policy actions are generally identified to stabilize food prices and keep consumers more food-and nutrition-secure (Dube et al., 2012). Governments, civil society, media and intergovernmental organizations (for instance WHO, OECD, etc.)

discuss on economic tools to address the affordability of food and change incentives for purchase, in different geographical contexts [START_REF] Hawkes | A food policy package for healthy diets and the prevention of obesity and diet-related non-communicable diseases: the NOURISHING framework[END_REF]. Through the regulation of prices, policy actions can have a strong impact on obesity and food related non-communicable diseases [START_REF] Webb | Medium-to long-run implications of high food prices for global nutrition[END_REF]. For instance, several international bodies advocate economic and fiscal policies to endorse the consumption of healthier foods, ameliorate the nutritional quality of diets, and fund population health programmes [START_REF] Lee | Monitoring the price and affordability of foods and diets globally[END_REF]. More broadly, in order to regulate the affordability of foods on the basis of their healthy attributes, food prices can be generally controlled by governments through a number of complex policy approaches. Pricing strategies, at a national level, can comprehend taxes on specific foods (soft drinks), exemption of value added tax for selected food groups (vegetables), and subsidies (agricultural and transport subsidies, voucher systems for high-risk groups) (Powell & Chalouppka, 2009;[START_REF] Sassi | The Obesity Epidemic: Analysis of past and Projected Future Trends in Selected OECD Countries[END_REF]. With regards to the impact of policy actions on the dietary energy balance and the satisfaction of cultural food preference, it is likely that the direct impact affects first the affordability of food through regulation of prices.

Furthermore, experts proposed a wide range of drivers that is possible to identify in the broad set of Changing agrofood patterns. This driver relates to the dynamics that shape the structure of the food systems and the relationships within the food valuechain elements and stakeholders including the steps of production, trade, distribution, consumption, and waste [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. The quality and concentration of markets and supply, and the power relationship between stakeholders within the value-chain are essential for achieving adequate food system outcomes. These factors also shape production capacity and patterns and have an impact on both the demand and production elements of food systems [START_REF] Eakin | What is Vulnerable?[END_REF]. For instance, with regards to the typology of food production and the distribution structure, the increasing level of processed food sales it is a symptom of a double phenomenon. If on the one hand the food sector is able to meet and follow the food preferences of consumers and their purchasing power level through providing highly processed foods, on the other handsince food consumption is increasingly turned towards this products [START_REF] Regmi | New directions in global food markets[END_REF] -marketing can strongly influence youngest food preferences putting these generations at risk of obesity, diabetes and food-related health problems [START_REF] Nestle | Food industry and health: mostly promises, little action[END_REF][START_REF] Liverman | Food systems and the global environment: An overview[END_REF]. However technological innovations are largely applied for producing highly processed foods, that can have a negative impact on health and be, in the meantime, nutrient-poor.

Participants also suggested analyzing the impact of technological innovation on the nutritional quality of food supply. Technological innovation in the food system relates to advancements converging between bio, nano and information technologies. The productivity of agriculture will be improved through appropriate advanced technology and management techniques for resources and land. New technologies and techniques can lighten pressure on environmental and economic resources and help solving sustainability problems [START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF]. Thus, technological advances can be powerful drivers of change in term of resilience of the nutritional quality of the food provisioned [START_REF] Misselhorn | Vulnerability to what[END_REF].

Soil degradation was the only environmental driver, within the newly proposed drivers of change, that was analyzed in this section (see figure 11). It was, therefore, suggested to explore the interaction between soil degradation and nutritional quality of food supply. Soil degradation affects human nutrition and health through reduction in the quantity and quality of food produced. Furthermore soil degradation implies pollution of soil and water with resultant impacts on human health. Hence, soil quality is considered as a key aspect of nutrition-sensitive agriculture, since it can help improving human nutrition [START_REF] Keding | Production and processing of foods as core aspects of nutrition-sensitive agriculture and sustainable diets[END_REF].

Several experts also mentioned the interest for analyzing the potential impact of world population dynamics on dietary balance. Finally, this interaction was mostly ranked as not important even though urbanization and migration, two of the most representative population dynamics, are widely acknowledged to be responses to poverty and lack of employment. For instance, observing that obesity increases as long as time passes after migration, it is now acknowledged that the impact on people's weight is consistent with an improved income level. This is similarly observed for diabetes prevalence. In UK, US and Canada it has been observed that the children of immigrants may be at even higher risk of obesity and diabetes than their parents [START_REF] Cairney | Time since immigration and excess body weight[END_REF][START_REF] Kaplan | The association between length of residence and obesity among Hispanic immigrants[END_REF][START_REF] Candib | Obesity and diabetes in vulnerable populations: reflection on proximal and distal causes[END_REF]. Thus, the reason why experts did not find important the impact of world population dynamics on dietary energy balance, may it refer to the geographical context of this Delphi study (France, Italy and Spain)? It has to be reported that France, Italy, and Spain fall within the 11 countries most inhabited by foreign-born population in the world (UN, 2014).

The reflection that emerged from the proposition and the appraisal of these new interactions shows that there is no unique interpretation for each impact of a driver of change on a food and nutrition security impact. Often impacts can be either positive or negative. Thus, geographical-and context-specificity of food security issues remains key, vis-à-vis global or regional drivers of change. The contribution of inputs from experts through a Delphi study can significantly help identifying and understanding these contradictions.

Discussion on Food and nutrition security issues

Delphi participants were asked to propose further food and nutrition security issuesspecific to the geographical context considered (Spain, France and Italy) -beyond the four issues presented in the initial framework. Respondents suggested 5 additional issues comprehending environmental externalities, social equity, physical accessibility, food safety, and food governance. In a following step experts assessed the all set of initial and newly proposed food and nutrition security issues.

Whether environmental and social welfare are two of the three main food system outcomes, which include food and nutrition security issues such as availability, access and utilization (Ericksen, 2008a;Ingram et al., 2010), these two newly proposed issues -environmental and social -cannot be considered as conventional food and nutrition security issues, as usually encountered in the literature [START_REF] Pangaribowo | Food and nutrition security indicators: a review[END_REF]. Since the mid-80's, several scholars and international organizations have been proposing the concept of "sustainable food security" (UN, 1987;[START_REF] Speth | Towards sustainable food security[END_REF]UN, 1996) or "sustainable food and nutrition security" today -as an enlarged concept of food and nutrition security considering environmental and social issues.

Simultaneously, the term "sustainable food and nutrition security" has been used

literally "to address the longer term, root causes of hunger and malnutrition" [START_REF] Thompson | Addressing the dynamics of agri-food systems: an emerging agenda for social science research[END_REF] as a forward-looking concept characterizing the ability of food systems to sustain food and nutrition security. The connections between these two understandings are not clear. And further analysis and debate would be necessary to acknowledge, not only conceptually but also in practice, the introduction of environmental and social concerns into food and nutrition security issues and the related tradeoffs to adopt towards the sustainability goals.

Experts provided appraisal on the importance level of the global set of issues, and each disciplinary group may have provided different opinions. As mentioned above the sample does not allow a representative analysis between disciplinary groups.

However -with regards to the most represented disciplinary groups (Economists and Nutritionists) -through a descriptive analysis, it is possible to perceive differences in the appraisal of the issues between these groups (see Table 8). On average, both groups contributed positively to the judgment of environmental and social issues and nutritionist appear to be more concerned by social equity. It is interesting to observe that each of the two groups seems to consider less important the issues that should be rather related to their own disciplinary background. For instance economists contribute negatively -on average -to the level of importance of the issues "affordability" and "accessibility" of food. Besides, nutritionists in comparison with other experts rank the importance of the issues "dietary energy balance", "food safety", and "satisfaction of cultural food preferences", under the average of the global panel. On the other hand nutritionists fostered rather "affordability" of food and "accessibility". The main discrepancies between the two groups are manifest with respect of the judgment for "accessibility", "food safety", and "food governance".

Should we think nutritionists are more aware about the problems encountered by people living in areas that are considered "food deserts" and about all the related nutritional consequences? Do nutritionists have more information about the level of "food safety" in the geographical region considered and are enough confident with it?

Are the economists more concerned by the economic risks of a safety-driven food crisis? Are nutritionists disappointed by the outcomes of previous food policies, or they are totally satisfied with them and think there is no need for further improving "governance"? Do the economists, instead, think that "food governance" can really contribute to food and nutrition security and further efforts are still necessary?

In interdisciplinary studies participants provide various skills to research efforts and it is essential to consider the values that different experts bring to the debate on food sustainability. This may help for exploring the food systems and for resolving some differences and making progress.

Geographical context

The choice of the geographical area of study, the Latin Arc (see pages [110][111]

Methodological considerations

Suitability of the Delphi as a method

The Delphi method is a structured process for collecting knowledge from a group of experts by means of a series of questionnaires interspersed with controlled opinion feedback [START_REF] Adler | Gazing into the oracle: the Delphi method and its application to social policy and public health[END_REF]. In socio-ecological vulnerability assessment it is highly recommended to conduct expert judgment through the Delphi method, in order to ensure maximum objectivity [START_REF] De Lange | Ecological vulnerability in risk assessment-a review and perspectives[END_REF].

Expert opinion is often the only source of evidence when no data are available and when data are difficult to attain at affordable costs, time and due to given the complexity of environmental systems [START_REF] Brooks | Global biodiversity conservation priorities[END_REF][START_REF] Burgman | Expert status and performance[END_REF][START_REF] Krueger | The role of expert opinion in environmental modelling[END_REF][START_REF] Vrana | A group agreementbased approach for decision making in environmental issues[END_REF]. In this research the Delphi method was applied because of its expert elicitation capabilities for complex systems and for the possibility to conduct a selection of indicators avoiding -through anonymity and control feedback -the problems of freely interacting groups such as the dominant individuals and the pressures to conform the majority of opinions. Providing individualized feedback from each round [START_REF] Steyaert | Participatory methods toolkit-A practitioner's manual[END_REF] allows informing participants on the majority of opinions and this can generate the modifications of the opinion of the minorities [START_REF] Bolger | Improving the Delphi process: lessons from social psychological research[END_REF]. In this way consensus usually increases after each round [START_REF] Orsi | Towards a common set of criteria and indicators to identify forest restoration priorities: An expert panel-based approach[END_REF].

In this research, several elements might have contributed to achieve appropriate levels of participation and to generate consensus.

With regards to participation, this might have been encouraged because of having an institutional support (see Annexes 1 and 2) that guarantees the beneficial purpose for society and not an exclusively profit-seeking aim for the team running the study [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF]. It was also mentioned that a Technical workshop, effectively held in Montpellier on November 2014, would have been organized at the end of the Delphi study and that participants would have been invited for further scientific discussion on the results of the elicitation process. Experts' collaboration might have been also

positively influenced because of an appropriate setting of a plural team with a very good knowledge and understanding of the problems of the sustainability of the food systems; experts can feel to make an effective contribution to the theme being studied and this enhance their motivation to participate [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF]. Allowance of conomination between colleagues might have also contributed to the latter point (Tapio, 2009). Furthermore, excessive attrition of participants has been avoided also thanks to the valuable recommendations for managing, motivating, feedback administrating obtained from the pilot application that was carried in two preliminary focus-groups [START_REF] Jairath | The Delphi methodology (Part one): A useful administrative approach[END_REF]. Sending qualitative personalized feedback with comments, explanations, and suggestions from the experts might have helped to create a real interaction of the group and then keeping adequate participation [START_REF] Mckenna | The Delphi technique: a worthwhile research approach for nursing?[END_REF][START_REF] Rowe | Judgment change during Delphi-like procedures: The role of majority influence, expertise, and confidence[END_REF]. The utility of Internet approaches to Delphi in allowing for consulting large, geographically dispersed, expert communities [START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF], was confirmed in this Delphi study. Also English as base language of the survey contributed to involve international and multidisciplinary participation; also, from this survey it does not seem that English represented a barrier for non-native English speakers. Another factor that might have contributed to Delphi participation is the double-edged sword of providing scientific contents and materials to participants.

In fact, if on the one side it is recommended not to overload participants with materials, on the other side it is considered essential that experts be aware of the seriousness and relevance of the study [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF][START_REF] Mckenna | The Delphi technique: a worthwhile research approach for nursing?[END_REF]. Related with this last point, the Delphi survey was structured to make each round less timeconsuming than the previous one.

With regards to the elements that might have contributed to generate consensus in this

Delphi study, it has to be reminded that consensus was globally reached on the set of indicators, drivers, issues and interactions, but for some indicators bipolarity and dissension emerged. The reasons of consensus (and of dissension) may lie on the several hypotheses and scientific arguments that led to the identification of the various research questions proposed, and on the experts' skills, background, and scientific perspective of sustainability of the food systems. However, there are general factors that have been reported as influencing the capacity of a group to reach consensus. In fact it is usually acknowledged that in Delphi group dynamics low status group members tend to 'go along with' the opinion of group members with a higher status and a group or a dominant group member tend to exert undue influence on the opinion of the group [START_REF] Gupta | Theory and applications of the Delphi technique: A bibliography (1975-1994[END_REF]van Zolingen & Klaassen, 2003, p. 318;[START_REF] Bolger | Improving the Delphi process: lessons from social psychological research[END_REF]. Moreover this factor further highlights the importance of the anonymity in Delphi studies as a main advantage that encourages experts to make statements on the basis of their personal knowledge [START_REF] Snyder-Halpern | Indicators of organizational readiness for clinical information technology/systems innovation: a Delphi study[END_REF].

Disadvantages of the Delphi technique have also been identified in literature and scholars have questioned the reliability, validity and credibility of this research methodology. [START_REF] Sackman | Delphi critique; expert opinion, forecasting, and group process[END_REF], for example, has noted that anonymity may lead to a lack of accountability because responses may not be traced back to the individual.

Todays' Internet approaches allow tracking responses of participants, but for evident scientific and ethical reasons facilitators are not allowed to divulgate this information.

In addition, it has been suggested that a consensus approach can lead to a diluted version of the best opinion and the result represents the 'lowest common denominator' (Powell, 2003, p. 378). It could be argued, however, that all approaches (for example, working groups, nominal groups) to gaining consensus run this risk. Others have argued that this approach is time-consuming, labor intensive and, therefore, expensive [START_REF] Fitzsimmons | Service management[END_REF] although there is not agreement about this [START_REF] Powell | The Delphi technique: myths and realities[END_REF]. A number of methodological issues arising in respect of Delphi have the capacity to threaten the credibility of the study and these include issues around panel expertise, number of rounds, questionnaire development, analysis and achievement of consensus [START_REF] Hanafin | Review of literature on the Delphi Technique, National Children's Office[END_REF].

Considerations of a Delphi application to a vulnerability and resilience indicatorapproach

In this study the Delphi method has been applied to generate a common understanding, and a consensus, within a scientific research group to provide assessment tools for policy making on sustainable diets and food systems, through a vulnerability and resilience framework. However there are a host of existing decision support tools that provide decision makers with evidence-based support on how to make decisions under risk and uncertainty [START_REF] Keeney | Decisions with multiple objectives: preferences and value trade-offs[END_REF][START_REF] Zeckhauser | The economics of catastrophes[END_REF]. Meanwhile these approaches did not completely proved appropriate to manage the complex issues associated with global change [START_REF] Webster | The curious role of" learning" in climate policy: should we wait for more data?[END_REF][START_REF] Wilby | SDSM-a decision support tool for the assessment of regional climate change impacts[END_REF][START_REF] Tol | Is the uncertainty about climate change too large for expected costbenefit analysis?[END_REF]. Thus it is highly recommended consulting with experts and users in finding solutions for social-ecological systems' problems (de Franca Doria et al., 2009).

The Delphi technique offers a structured approach to collecting data in situations where the only available alternatives may be subjective approaches [START_REF] Broomfield | Using the Delphi technique to identify the cancer education requirements of general practitioners[END_REF]. The main purpose of a Delphi application to the selection of indicators was to go beyond choosing indicators on the basis of the availability of data or through subjective and value judgment decisions of an individual [START_REF] Linstone | The Delphi method: Techniques and applications[END_REF]. Other group approaches to reaching consensus have been found to be less appropriate to the development of sets of indicators. The main disadvantages with technique such as nominal groups [START_REF] Carney | The use of the nominal group technique in research with community nurses[END_REF], brain-storming [START_REF] Hasson | Research guidelines for the Delphi survey technique[END_REF], focus groups [START_REF] Morgan | Focus groups as qualitative research, Sage Research Methods[END_REF] and analytic hierarchy process (AHP) technique [START_REF] Lai | Group decision making in a multiple criteria environment: A case using the AHP in software selection[END_REF], and working groups is their risk of considering only the perceptions of the most outspoken or opinionated members of that group or only focusing on interesting or controversial elements. Similarly, the review of methods currently used to assess vulnerability, both in ecological studies as in social-ecological studies, reveals that assessments strongly depend on expert judgment. This can be seen as an advantage, e.g. by the use of state-of-the-art knowledge which can be adapted when new insights become available [START_REF] De Lange | Ecological vulnerability in risk assessment-a review and perspectives[END_REF]. However, it can also be regarded as a disadvantage, because it is not clear how experts arrive to their judgments. This drawback can be overcome by using a standardized method, such as the Delphi method [START_REF] Dalkey | An experimental application of the Delphi method to the use of experts[END_REF].

The Delphi's participatory nature and the rigorous queries can enable close collaboration between researchers, with the aim of informing decision makers. This could enhance the scientific and policy relevance of the structured results of this application of the vulnerability and resilience framework. This adaptation of the vulnerability and resilience framework can represent an instrumental approach to be used with the Delphi method for similar future research on the assessment of the sustainability of diets and food systems. In the larger context of social-ecological systems frameworks, this approach is often associated to shortcomings especially derived from a lack of agency in programmes and scarce communication from researchers to policy-makers [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. Starting from this Delphi study -its anonymity, iterative characteristics, and the statistical consensus -the pitfalls of the vulnerability and resilience approach applied to the sustainability of the food systems could be overcome by favoring a critical verifiable generation of group communication and information.

Use of Delphi method is not free from criticism. [START_REF] Keith | When is it appropriate to combine expert judgments?[END_REF] proposes, for analyzing uncertainty issues in climate change, to focus on alternative ways in which policymakers use science rather than eliciting expert to inform them. Testing the appropriateness of expert elicitation still remains a challenge (de Franca Doria et al., 2009).

The indicator approach that we applied is based on the vulnerability and resilience framework and uses a specific set or combination of indicators (proxy indicators)

proposed to measure and explore the sustainability of diets and food systems. This approach is here applied at subnational level, but can be applied at any scale (e.g., household, county/district, national, system) through a context-specific selection of indicators. The major limitation of the indicator approach is its inability to capture the complex temporal and social dynamics of the various systems being measured.

Differently from similar indicator-base approaches [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF] the subjectivity in the selection of variables was avoided by applying the Delphi method.

However further efforts will be needed to establish or not relative weights, to identify the availability of data at various scales or the need for further retrieval, to test or validate the different metrics [START_REF] Luers | A method for quantifying vulnerability, applied to the agricultural system of the Yaqui Valley, Mexico[END_REF], and to respect the essential criteria for validation indicators (OECD, 2008). However, the indicator approach is valuable for monitoring trends, exploring, and operationalizing conceptual frameworks. deductive or normative arguments. Whatever be the best argument classification of this work's approach, the deductive arguments or an integration of deductive and normative ones, the Delphi method represents a rigorous and reliable method to handle with collective value judgments of experts [START_REF] Linstone | The Delphi method: Techniques and applications[END_REF][START_REF] Landeta | People consultation to construct the future: a Delphi application[END_REF].

The indicator approach is the most common method adopted for quantifying vulnerability in the global change community [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF]. [START_REF] Leichenko | The dynamics of rural vulnerability to global change: the case of southern Africa[END_REF] highlighted the opportunity to capture the multi-dimensionality of vulnerability in a comprehensible form through composite indices. Vulnerability indicators are necessary for practical decision-making processes not only to provide policy makers with appropriate information for the identification of zones of vulnerability, but also to improve their understanding and knowledge of action on the causal mechanisms that are underneath the sustainability of the food systems and that emerge through a vulnerability and resilience analysis [START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF]. The indicator approach is then used to develop a better understanding of the socioeconomic and biophysical factors contributing to vulnerability [START_REF] Hebb | Floods: Mapping Vulnerability in the Upper Thames -Watershed under a Changing Climate, CFCAS Project Assessment of Water Resources Risk and Vulnerability to Changing Climatic Conditions[END_REF]. This Delphi study represents also an opportunity to test in practice a vulnerability and resilience framework adapted from the Turner et al.'s (2003) vulnerability/sustainability framework, and to improve the agency of the application through selecting indicators. This kind of framework is often considered to difficult and complex to apply [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF], however a system analysis still needs to take into account the non-linear mechanisms that regulate complex systems, and a multidisciplinary expert elicitation represent a way to tackle such a challenging issue.

Why choosing the Delphi method instead of other techniques

There are a host of existing decision support tools that can guide decision makers in formulating decisions under uncertainty [START_REF] Keeney | Decisions with multiple objectives: preferences and value trade-offs[END_REF][START_REF] Zeckhauser | The economics of catastrophes[END_REF]. For instance, in eliciting views on complex climate issues, various research tools, involving experts in an iterative process of problem definition and analysis have proven useful, including Delphi approach and other expert elicitation tools (De Lange et al., 2009).

As mentioned above, the Delphi method was applied in this study for several reasons (pages 134-136 and 168-172 of this thesis), according also to several similar studies, including research on global changes, sustainability of systems, and identification and selection of sustainability indicators, in which this methodology proved to be key (pages 134-135 of this thesis).

However, there are a number of methodologies that could have been applied, as alternatives to the Delphi method.

For example Structured Knowledge Acquisition Techniques represent a set of methodologies that involve task analysis, protocol analysis, structured interviews and simulation activities, and can be used with expert participation, individually or in small groups. In particular, [START_REF] Mcgraw | Knowledge elicitation with multiple experts: considerations and techniques[END_REF] provided a review on how three knowledge acquisition methods proved useful for the elicitation processes, engaging multiple expert team, such as brainstorming, consensus decision-making and the nominal group technique.

Brainstorming was found useful especially for initial meetings with several experts within a group dynamics, allowing the identification of unattended and unconventional valuable responses and solutions to a critical issue. However, since the identification of solutions is realized in an open manner within a group dynamics, it is important to consider the potential effect of academic authority or strong personalities of participants.

Consensus decision-making allows analyzing strengths and weaknesses of any solutions identified, for a specific issue, through assessment and weighting from the multiple expert team members. The knowledge engineer provides the group with a descriptive background to orient the team towards the consensus and, therefore, his/her personal and professional characteristics and behavior are central for the success of the process. It is crucial that he/she considers all the possible effects of the status, rank, and background among each expert of the panel.

The Nominal group technique can avoid the disequilibria of a face-to-face approach within the group dynamics, through and elicitation process where group members can function independently and anonymously.

These three methodologies imply the organization of a number of meetings to get the first findings for decision-making and also the engagement of an experienced and specialist knowledge engineer who could avoid unbalances within the group dynamics (especially in brainstorming and consensus decision-making) [START_REF] Mcgraw | Knowledge elicitation with multiple experts: considerations and techniques[END_REF].

Other methodologies for decision-making and knowledge elicitation refer to Soft Systems approaches [START_REF] Checkland | Systems thinking, Systems Practice[END_REF]. These methodologies can imply traditional elicitation approach in the social sciences and using of semi-structured and one-to-one interviews conducted with key stakeholders. In particular this kind of techniques were applied through the "Imagine" methodology to reach a list of sustainability indicators [START_REF] Bell | A practitioner's guide to 'Imagine', the systemic and prospective sustainability analysis[END_REF], in the Blue Plan Coastal Area Management Programme (CAMP) project, via participation with a range of local stakeholders. The "Imagine" methodology was initially based on the soft systems approach of Peter Checkland [START_REF] Checkland | Systems thinking, Systems Practice[END_REF] and on the approaches of a "systemic sustainability analysis" [START_REF] Bell | Sustainability Indicators. Measuring the Immeasurable[END_REF] that help in getting the complexity of sustainability and the related multiple perspectives, through identifying sustainability indicators with the participation of key involved stakeholders.

Also, in the in the European Union Seventh Framework Programme (FP7/2007-2013), in particular in the POINT (Policy Influence of Indicators) project, the Triple Task methodology was adopted for implementing participatory action research and stakeholder analysis, not only to reach solutions to research problems but also to understand the factors actually involved in identifying those solutions. This methodology implies the organization of five to six workshops, involving about 20 people (Bell and Morse, 2010).

The adoption of these techniques allowed producing a holistic perception of the specific systemic contexts in an inclusive and participatory manner [START_REF] Bleu | Final Report on the Systemic and Prospective Sustainability Analysis Project within CAMP Malta[END_REF][START_REF] Cassar | Assessing the use and influence of sustainability indicators at the European periphery[END_REF]. They are participant-led rather than researcher-led and, therefore, can provide unobvious and valuable innovative understandings [START_REF] Campbell | A critical appraisal of participatory methods in development research[END_REF].

However such approaches are time-consuming (2 days for each workshop), costly, and do not help identifying comparisons between each participant, while any input provided by individual participants have been also framed by their interaction with others [START_REF] Cassar | Assessing the use and influence of sustainability indicators at the European periphery[END_REF].

There are two main sets of explanations why the Delphi method was preferred, for this specific project, to other elicitation methodologies:

1) Institutional and resource availability reasons that implied making choices considering the timeframe and the number of experts to involve;

2) Reasons linked to the academic level of the experts involved and the related influence on the group dynamics, and the consequent required role of the knowledge engineer.

Basically the Delphi method was favored because it better fitted the time and resource constraints of the project, allowing gathering a group of 50 experts and working with rigorous and a well defined technique applicable also by non-specialist users.

First, institutional and funding-related intentions needed to be fulfilled with the organization of a conclusive event, including the presentation of results to create awareness and visibility within the research community, and gathering a community of experts working on food systems trying to discuss and identify the different understanding of sustainability for the food system.

Initially, within the aforementioned project, the intent was to elicit groups of experts through a number of meetings at different stages. The objective was to involve a maximum of a dozen of experts, in order to get views and consensus on a set of indicators to study the sustainability problems of the food system, through a resilience and vulnerability adapted framework. At this stage, the methods that could have been envisioned to elicit experts would have involved a number of various and different techniques such as Soft-System Methodology, Consensus methodology, Delphi method etc.

Then, as the conceptual and findings were based on solid and recognized conceptual frameworks, and allowed to envisage further interesting research development, the partnerships between the institutions could imply a greater motivation and involvement of means. The purpose was, therefore, to augment the participation of experts to a larger number of people of about 50 participants, and also to give more institutional visibility, in order to create further awareness and visibility on the food system sustainability problems addressed by the project. A main goal was also to explore the common understanding of the sustainability of food systems, within a high level academic community. Furthermore, the objective was also to create a community of expert, also for exploring further perspectives of common research and action for sustainable development. These goals, therefore, involved the need to present and discuss the final results, from the shared indicator selection, in a unique event that would give the opportunity to expert to discuss, analyze, and judge the findings, and to gather efforts for further partnerships. The institutional support was then linked to this event, that could justify, in the end, the employment of means and resources. The choice of the methodology was, therefore, also conditioned by the availability of resources, at a given time, for a conclusive event of restitution of results. The perspective of a conclusive event, seminar, is also considered key to encourage the participation of experts in a lengthy elicitation process [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF].

The Delphi method was identified as a methodology that provides a rigorous scientific process, that is time consuming, and that, if conducted appropriately, can lead to quantitative and consistent results, at the end of the process. On the other hand, the application of Soft System methodologies would have implied the organization of a number of meetings, and this would have needed the availability of means at an early and intermediary stage, and also a constant support over the meetings, before obtaining quantitative results on the indicator selection.

Second, given the high academic level of the participant, knowledgeable elicitators and knowledge engineers are strongly challenged to guarantee equilibrium within the group debate, avoiding unbalances created by authority and personality effects, and assuring high level skills in group dynamics and leadership, gaining consensus and resolving conflict [START_REF] Mcgraw | Knowledge elicitation with multiple experts: considerations and techniques[END_REF]. These prerequisites could be avoided through remotely managed methods and anonymous consultation and elicitation, that can be lead by non-specialists elicitators who would rather be able to apply and follow rigorous methods and guided processes for expert elicitation. The Delphi method, for its highly defined scientific rigor, is a methodology that can be learnt and is frequently applied by non-specialists scholars.

Furthermore, an EFSA study on "Expert Knowledge Elicitation in Food and Feed Safety Risk Assessment" (2014) compared the Delphi method with two other elicitation methodologies, such as the Sheffield and the Cook techniques. Many differences emerged between those methods. The analysis of this comparative evaluation confirms the validity of the factors that have been identified for the choice of the Delphi method, as mentioned above.

Differently from the methodologies that imply the organizations of meetings and workshops, where experts gather in groups and discuss on the solution of critical problems, the Delphi method is rather applied remotely and with written materials.

This prevents direct interactions of experts that would be biased by unequal knowledge of the English spoken language (EFSA, 2014), in addition to the above mentioned authority effects.

The approaches analyzed in this study, that involve the organization of experts, comprehend 6 to 10 participants (EFSA, 2014), while the Delphi method allows gathering dozens of experts, as it was actually envisaged for the specific project related to this thesis.

In addition, Delphi is considered the least demanding approach for the experts, because of the written format and the adaptable timeline, avoiding requiring attendance at workshops or at individual face-to-face sessions (EFSA, 2014). This factor allows keeping constant and acceptable participation of experts (about 50 people), and does not require implying resources for supporting intermediary workshops. Thus, the use of Delphi method initially concentrates the resources on staff costs, rather than for organizing intermediary workshops.

5-5 Conclusions

The aim of this section of the thesis was to identify a consensus on a reduced set of indicators of exposure, sensitivity and resilience -within a larger set proposed to a panel of expert -to find solutions and tools for the assessment of sustainable diets and food systems. This goal was achieved through combined use of the participatory Delphi method and the vulnerability and resilience framework. The identification of these indicators, and the understanding of the drivers of change, and of the food and nutrition security issues, would allow retrieving basic information to describe and measure the sustainability of the food systems face with global and regional socioeconomic and biophysical changes.

Following the guidelines for conducting Delphi research we obtained acceptable response and participation rates, and a balanced composition of the panel of experts from different disciplines. The Delphi study was conducted over three iterative rounds and high, medium, low and majority of consensus was progressively obtained on 75%

of the interactions proposed. The drivers of change and food and nutrition security issues proposed in the framework were widely judged important, as well as the interactions presented. Furthermore, participants contributed to enlarge the set of drivers and issues and the related new interactions. The panel highlighted the importance of a number of these new propositions of interactions that will generate further hypotheses and will likely be considered for further research on problems related to the sustainability of the food systems through a vulnerability and resilience framework.

Further analysis of the socioeconomic and biophysical aspects of the sustainability of diets and food system could use or adapt the results of this Delphi study, not only by using the indicators, but also adapting the framework and the approach to other problems affecting the sustainability of the social-ecological systems at global, regional, national or local level. These efforts could be focused on support for decision-making.

This study has proved that the participatory approach -through the Delphi methodis a tool to gather opinions and forge group consensus. Delphi has demonstrated to be an efficient, versatile method capable of integrating knowledge of a panel of researchers. However, evaluation of the actual interest of the outputs of Delphi surveys into policies remains a topic that needs additional attention in order to demonstrate the actual effectiveness of the Delphi method.

The limits of this study, beyond the application of a vulnerability and resilience framework that is widely acknowledged and cited but also criticized, relate basically to the reduced number of interactions proposed, to the composition of the panel, and to the availability of the data for the indicators. However, the topics tackled by this framework can be opened to further research questions related to the sustainability of the food system. Furthermore, the preference for indicators that are not yet measured can encourage further retrieval of data for supporting decision-making. Although participation rate was acceptable and composition of the panel was constantly diversified all over the Delphi process, these aspects of a Delphi study can always be improved.

Chapter 6

General conclusions

This thesis aimed at developing a multidimensional framework, to identify metrics for assessing the sustainability of food systems and diets, applicable at a subregional level. Building on Social-Ecological Systems frameworks, the Mediterranean Latin Arc presents several socioeconomic and biophysical drivers of change making the food system vulnerable in its functions. A vulnerability/resilience approach was applied to analyze the main issues related to food and nutrition security. Formalizing the food system as a dynamic system, a model originates from this framework.

Several causal models of vulnerability were identified, describing the interactions where drivers of change directly affect food and nutrition security outcomes, disentangling exposure, sensitivity, and resilience. This theoretical modeling exercise allowed the identification of a first suite of indicators. A reduced pool of metrics was then obtained through an expert-based elicitation process (Delphi Survey), moving beyond subjective evaluation and reaching consensus.

Vulnerability per se is considered unobservable; since it does not express an observable phenomenon it is a theoretical concept that cannot be measured [START_REF] Patt | An introduction to the diversity of approaches to vulnerability research and assessment: common features and lessons learned[END_REF]. Before measuring vulnerability, therefore, it is necessary to make the concept operational providing a method for framing it into observable concepts. This operational definition can be identified as vulnerability assessment, and indicators represent an appropriate approach to operationalize the theoretical concepts [START_REF] Walker | Resilience and vulnerability: complementary or conflicting concepts[END_REF]. Indicators are the functions of indicator-based approaches. In this thesis the arguments for identifying vulnerability indicators were deductive arguments (based on existing theories, models and frameworks). In particular it was adapted the general framework of [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF], for social-ecological systems, to the food system framework of Ericksen (2008), fostering the operationalization of the theories of vulnerability and resilience through a set of causal models and the combination with literature review and expert judgment (another deductive argument for vulnerability indicators) [START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF]. Since data availability has not been the central criterion for identifying indicators, this work is based on a theory-driven approach (instead of a data-driven one) [START_REF] Niemeijer | Developing indicators for environmental policy: data-driven and theory-driven approaches examined by example[END_REF].

The general aim of this thesis was to analyze and explore the sustainability of the food system through identifying a set and a system of metrics at the Mediterranean level.

This general aim involved three specific goals that have been identified through a sequential logic. The first specific goal was to develop a multidimensional framework to evaluate the sustainability of food systems and diets, applicable to countries of the Mediterranean region. At this stage it was essential to develop a conceptual framework to link concepts, methods, and metrics, for a multidimensional joint analysis and a broad understanding of food and nutrition security and food system sustainability. The second specific goal was to identify the main variables to formalize and operationalize the abstract and multidimensional concept of sustainable food systems. It was key to identify the food system characteristics and fundamental systemic properties that make the food system capable of sustaining food and nutrition security outcomes. The third specific goal was to identify metrics for assessing the sustainability of food systems and diets, at a subregional level, combining a vulnerability and resilience framework and a Delphi elicitation process.

I. A conceptual hierarchical framework was identified for modeling the complex relationships between food and nutrition security and sustainability for the development of potential indicators of sustainable diets and food systems. Developing a conceptual multidimensional framework, to explore the sustainability of the food systems, implied adopting a broad sustainability approach that was reached through an extensive literature review on problems related to food and nutrition security (Chapter 1). The understanding of the food systems as a social-ecological system helped answering questions about the sustainability problems that affect the functions of the food system (Food system framework: Ericksen, 2008a). Food and nutrition security is considered the principal outcome of any food system and is a multidimensional concept and relies on several properties of food systems, categorized as a range of activities (Ingram et al., 2010). Various elements of food systems are altered by, and actively impact, the socioeconomic and environmental conditions of the system across local, regional and global levels. These interactions are featured by, and bring with themselves high uncertainties, that can be explored through a vulnerability and resilience analysis, being vulnerability the propensity or predisposition of a system to be adversely affected by a change [START_REF] Ipcc | Summary for Policymakers. Climate Change 2014: Impacts, Adaptation, and Vulnerability[END_REF]. Food systems can be vulnerable, and resilient, to a set of stressors [START_REF] Adger | Vulnerability[END_REF]) such as environmental pressures, socioeconomic instabilities and institutional and policy factors, and its vulnerability can be defined and observed through exposure, sensitivity and adaptive capacity (Vulnerability framework: [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF][START_REF] Ericksen | The value of a food system approach[END_REF]. A food system is considered vulnerable when it fails in delivering one or many of its intended outcomes, because of even small stresses that might bring to significant social-ecological consequences [START_REF] Adger | Vulnerability[END_REF][START_REF] Eakin | What is Vulnerable?[END_REF].

Fulfilling the food system outcomes remains challenging because of socioeconomic and biophysical stressors affecting the food system. Food systems are then considered social-ecological systems that comprise biophysical and social factors linked through feedback mechanisms (Ericksen, 2008a). Theories of vulnerability and resilience, within the wider context of social-ecological system frameworks, proved helpful in several researches to understand the complex dynamics involving socioeconomic and biophysical aspects (especially in ecosystem management), to implement sustainable development strategies and research programs. However the operationalization of social-ecological systems frameworks remains challenging and still interests mainly researchers and, to a lesser extent, decision-and policy-makers. [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF] suggest that the reason why practitioners do not tend towards these approaches resides on the systemic characteristics of these approaches. Practitioners, therefore, would prefer applying more focused tools rather than too broad and systemic approaches. In the meantime this kind of frameworks are adaptable and then able to be integrated with other methodologies and assessment tools, in order to be more operational [START_REF] Binder | Comparison of Frameworks for Analyzing Social-ecological Systems[END_REF]. Systemic understanding of the sustainability of the food systems can thus be further implemented also enlarging the research to multiple disciplines, multidimensional approaches, and integrated assessment and simulation tools to guide change (Chapter 2).

Hence, using the lens of a broad sustainability perspective, a multidimensional framework has been developed based on the vulnerability and resilience theories and assessment (Chapter 3). A causal-factors approach has been applied to study the sequential causal pathway defined by the relationship between exposure, sensitivity and resilience. Understanding the causal mechanisms that regulate the interactions between drivers of change and vulnerable food and nutrition security issues can help analyzing and interpreting available information, developing metrics, and anticipating new hazards and changes. The investigation on causes, effects and response to socioeconomic and biophysical changes can provide analytical tools to further understand the problems that affect the sustainability of the food system [START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]. This approach proved helpful for a general causal analysis of the vulnerability of the food system outcomes at a regional level, in the Mediterranean area. However it is still needed to clarify how the variables -belonging to exposure, sensitivity, and resilience -actually behave in a dynamic food system faced with several unattended socioeconomic and environmental drivers of change at multiple temporal and spatial scales.

II. Therefore, the research targeted the identification of the main variables to formalize and operationalize the abstract and multidimensional concepts of sustainable food systems. A feedback-structured framework of the food system (Chapter 4) formalized eight causal models of vulnerability and resilience, and identified intrinsic properties of the food system, shaping the interactions where external drivers of change directly affect food and nutrition security outcomes at a subregional level. The previously mentioned causal pathway to vulnerability was then clarified. The challenge for social-ecological system frameworks analysis, here, is to identify the pathways leading to vulnerability, and the characteristics and opportunities ensuring resilience of the food system in a context of change. The identification of a causal pathway (adapted from Metzger and Schroeter, 2006;Fussel and Klein, 2006) allowed locating the role of the three variables (such as exposure, sensitivity and resilience), with exposure referring to relational variable and characterizing the relationship between the system and its environment. Hence exposure represents the first point of contact between the stress or perturbation, and the system. The understanding of exposure, as the first interface with a specific driver of change, helps differentiating it from the sensitivity or resilience components, which might be influenced by other drivers of change. Building on the GECAFS food systems approach (Ericksen, 2008a,b;Ingram et al., 2010), coupled with Turner et al.'s (2003) conceptualization of vulnerability, it is suggested a framework representing the modeling of food systems' dynamics, with feedback from outputs to inputs. Dynamic systems consider mainly two types of variables: endogenous and exogenous variables. In the case at hand, these variables are defined at the national or sub-national level. On the contrary, outcomes from the food system activities may however contribute to these external drivers. The three components of vulnerabilityexposure, sensitivity and resilience -are the intrinsic features of the system that mediate the impact of the drivers of change on the food system's outcomes. These can be either state or control variables. This formalization of the food system dynamics allowed shaping eight causal models, in the geographical area of the Latin Arc, where the drivers of change and the food system outcomes of interest have been evaluated

through the analysis of their potential causal relationships. These sets of characteristics are indicating how changes in water, biodiversity, food prices and food consumption patterns are transmitted through the food system, including the sequencing of events and the scale of interactions; how the food system is sensitive to these changes; and the adaptive capacity of the food system. This could lead to subsequent work to identify thresholds of change and to model quantitatively the interactions among stressors, attributes, and outcomes, to improve the general understanding of food system sustainability. It more importantly offers the elements that need to be assessed, i.e. the attributes that indicators can be measuring.

III. The identification of crucial interactions within a complex food system, involving global and regional socioeconomic and biophysical drivers of change against a set of context-specific food and nutrition security issues, and the identification of a causal model where variables are the characterizing properties of a formalized food system, allow the definition of a set of metrics for assessing the sustainability of the food systems (Chapter 5). The aim is to select metrics for assessing the sustainability of food systems and diets, at a subregional level, combining a vulnerability and resilience framework and a Delphi elicitation process. Part of the aim is also to involve the participation of the scientific community in the selection of metrics.

Whether several expert elicitation processes exist, Delphi studies are considered performing tools that provide a common understanding and consensus on unraveled problems, avoiding problems related to institutional or authority influence between the experts. The vulnerability and resilience framework was used as an analytical lens to provide a sequential list of sustainability indicators, while the Delphi method was used to determine which indicators are perceived as more relevant according to a selected group of participants. The Delphi study was conceived, and managed, according to the recommendations of several scholars [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF][START_REF] Frewer | The use of Delphi methodology in agrifood policy development: some lessons learned[END_REF]. In particular this Delphi process was structured to achieve the main aim of this specific research: a consensus on a set of metrics of sustainable diets and food systems. This involved also the selection of the invited researchers on the basis of their characteristics. A crucial factor was the selection of metrics for the initial set of metrics. Each indicator was identified following a hypothesis. Each specific hypothesis would describe the behavior of a specific variable (of exposure, sensitivity, or resilience) lying underneath the causal mechanism that is occurring in each interaction between a driver of change and a food and nutrition security issue. The results, in terms of global response and participation rates and consensus on indicators, were judged acceptable [START_REF] Landeta | Current validity of the Delphi method in social sciences[END_REF]. These results confirmed the validity of the conceptual framework and methodology applied. However strengths and weaknesses of this approach appear belonging to the same aspects. If on the one hand it happened that the panel has selected metrics that are not measured with data - Furthermore, experts proposed also to enlarge the fields of the study through further drivers of change and food and nutrition security issues of the food system. There might be various perspectives for further research from these results, however, the Delphi method need to be managed in a way that could really be helpful for solutions, providing concrete and applicable outcomes, in order to offer decision-makers, stakeholders, and practitioners the possibility to fruitfully work throughout socialecological systems frameworks for improving action on sustainable food systems.

Scientific standing

This thesis deals with several research domains and mainly pertains to three research fields such as: assessing sustainability of diets and food systems, operationalizing of vulnerability and resilience theories, and the Delphi expert consultation method.

With regards to assessing sustainability of diets and food systems, it still does not exist a shared consensus on a set of metrics [START_REF] Vinceti | The contribution of forests and trees to sustainable diets[END_REF]. Research institutions, and governmental and non-governmental bodies produced a host of valuable efforts, both at national and international level, for identifying metric tools for the assessment of the sustainability of food systems [START_REF] Feenstra | Proposed Indicators for Sustainable Food Systems[END_REF]DEFRA, 2009;FAO, 2013b;[START_REF] Unsdsn | Indicators and a monitoring framework for Sustainable Development Goals[END_REF]. This work is meant to propose a scientific contribution, to the assessment of sustainable diets and food systems, building on robust theories (vulnerability and resilience within the social-ecological systems frameworks) and methods (vulnerability assessment and Delphi process) that already proven appropriate for food systems or social-ecological systems analyses. In this study, the analysis of the causal mechanisms underneath the sustainability problems of food systems is led through a theory-driven approach, based on deductive arguments. This scientific standing is different from the data-driven approaches (based of inductive arguments) applied to study the sustainability of the food systems.

In fact, the understanding of the changes affecting the sustainability of the outcomes of the food systems need to be studied through a systemic investigation of the dynamics that regulate the interactions between the different variables of a complex system. This discrepancy (from a data-driven approach) explains why, in this study, the selection of indicators belongs on single hypotheses built on theories, frameworks, and then on expert opinions, and does not originate from the general quantitative criteria that are generally proposed within the main and broad guidelines for indicators identification, such as SMART criteria [START_REF] Doran | There'sa SMART way to write management's goals and objectives[END_REF], or the principles of the European Statistics Code of Practice's (OECD, 2008), or the precepts of the indicators of Sustainable Consumption and Production (Watson et al., 2010).

However, a statistical robustness of data remains key in the process of quantitative assessment of indicators. Hence, a following phase contributing to further knowledge and assessment of sustainable diets and food systems needs to be supported, through a statistical validity of the measurement. Building on the selected metrics and on the identified data gaps and needs, an appropriate set of criteria to assess the overall quality of the indicators will need to be identified. With regards to the indicators defined and selected in this study to proxy the variables that describe the sustainability dynamics of the food systems, thanks to the rigorous approach applied, it might be possible to acknowledge their relevance to the sustainability problems of the food systems, their representativeness of the specific geographical context considered, as well as their interpretability through the identification of the hypotheses formulated. Nevertheless, the validity, reliability, consistency, availability, measurability, monitorability, cost effectiveness, and timeliness of the related data will still need to be tested in a next phase. A suitable approach, providing minimal quality criteria for measurement, can be found in the conceptual framework proposed by [START_REF] Cafiero | Validity and reliability of food security measures[END_REF] for food security assessment, that is based on the recognition of the validity of a measurement tool and the reliability of the measures it produces (including accuracy and precision). This approach has already been fruitfully tested [START_REF] Cafiero | Validity and reliability of food security measures[END_REF] through reviewing the validity, reliability and feasibility of a selection of food security indicators.

Limitations

The limitations of this work can be mainly identified in the theoretical approach, in the methodological framework, and in the results obtained.

The theories of vulnerability and resilience pertain to the social-ecological systems frameworks. With regards to the application of these theories to the analysis of the sustainability of the food systems, it is acknowledged that this theoretical approach interests mainly the scientific community rather than the community of development practitioners; its systemic nature would complicate and discourage the agency options [START_REF] Foran | Taking Complexity in Food Systems Seriously: An Interdisciplinary Analysis[END_REF]. However, in some cases practitioners might tend to consider metrics to measure sustainability as more important than scientists might do [START_REF] Dicks | What do we need to know to enhance the environmental sustainability of agricultural production? A prioritisation of knowledge needs for the UK food system[END_REF].

This specific limitation of the approach calls for further efforts, of application to food system studies and analyses, aimed at overcoming the pitfalls encountered. Within this broad systemic approach, that is hard to apply, this thesis attempted to provide a reductionist and operational analytic approach, refined through multidisciplinary and multi-stakeholders dialogue and interaction (i.e. the Delphi study), and aimed at contributing to the perspective of a science for sustainability [START_REF] Holling | Two cultures of ecology[END_REF][START_REF] Scoones | Dynamic Systems and the Challenge of Sustainability[END_REF] in food systems. However, the proposed fragmentation in specific vulnerabilities and resilience factors, through the intersections of different drivers and issues, induces a certain degree of linearity in causality. Then, as systems behave in a circular organization, this linear fragmentation could be deemed as excessively reductionist and not considering unattended feedback loops occurring within the food system. This factor may generate doubts from the scientific community because of the need of further and time-consuming modifications of the approach. In any case, a whole food system approach is often exposed to several critics for being too ambitious, or, to risks of insufficient analysis or applicability.

Analyzing the sustainability of the food systems through the identification of a set of metrics has the natural goal of contributing to a quantitative assessment. This study wants mainly to fill the theoretical and methodological gaps that are generally beneath a numeric assessment of sustainable diets and food systems. As it has already been mentioned, this work lies on a theory-driven approach and on deductive arguments and expert judgment, differently from data-driven processes and inductive and nonsubstantial arguments [START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF]. While robust theoretical and conceptual principles could represent a prior solid basis for a following statistical analysis, the contrary could appear less pertinent in any kind of measurement; "What is badly defined is likely to be badly measured" (OECD, 2008). In particular, this work reviews methods of assessment, cites data on food security issues and sustainability problems especially in the Mediterranean context, proposes a quantitative calculation, and selects metrics for sustainable diets and food systems but it does not actually quantify the variables emerged. Efforts are, thus, totally concentrated on the operationalization of the theories of vulnerability and resilience for defining a set of metrics of sustainable diets and food systems and for an expert-based selection.

Taking seriously these latter fundamental issues, accuracy is further challenged for subsequent data retrieving and statistical robustness. Moreover several selected indicators are not yet computed in the geographical area analyzed. Further research, therefore, could stem from the outcomes of this work and lead to quantitative results, still considering suitable criteria for adopting valid and reliable metrics [START_REF] Cafiero | Validity and reliability of food security measures[END_REF]. Starting from the elements that need to be assessed and knowing the attributes that indicators can be measuring, subsequent work could identify thresholds of change and model quantitatively the interactions among stressors, attributes, and outcomes, to improve the general understanding of food system sustainability.

In addition, other food systems' outcomes than food and nutrition security issues could also have been studied, such as environmental and socio-economic outcomes related to employment or equity. Food systems, in fact, are responsible for various environmental, economic and social outcomes. Incorporating these issues would have maybe matched better the general understanding of sustainability. The set of food systems' outcomes and defining elements could, therefore, be extended to other dimensions to further develop the modelling approach, since sustainability can hardly be modeled parsimoniously. This would then originate questions in terms of feasibility of the modeling.

Implications for further research

The theoretical background, the results, and the limits of this work can help identify further research perspectives. This research may offer a set of opportunities for further analyses on the sustainability of the food systems, thanks to a dynamic framework, together with robust theory-driven approach and deductive arguments for selecting the indicators, combined with a rigorous Delphi study.

The framework comprehends four main drivers of change, such as Water depletion, Biodiversity loss, Food price volatility, and Changes in food consumption patterns that are acknowledged for being key in affecting the sustainability of the food systems. The interactions between these drivers and a set of major food and nutrition security issues, such as Nutritional quality of food supply, Affordability of food, Dietary energy balance, and Satisfaction of cultural food preferences, are tested as they are considered crucial in the geographical region considered (see chapter 4). On the one hand this framework provides the opportunity to further investigate these current key socioeconomic and biophysical changes, acting on the food systems, and the food and nutrition security problems specific to the limited geographical context of the Latin Arc. Some of these elements have been studied in literature more than others. However the set of interactions might provide further original and inspiring research developments. For instance, describing and assessing the links between all the drivers of change with the nutritional supply (and not the caloric supply), the interplay between the loss of biodiversity and the food preferences, and the interaction between water scarcity and food access, represent challenging questions that are emerging in food systems' research and might lead to interesting scientific novel contributions for the assessment and understanding of the food system sustainability problems. On the other hand, as already stated and also attempted in the Delphi study The selection of metrics presented might be used for evaluating the sustainability of diets and food systems for the drivers and issues considered, in the Mediterranean Arc, through a vulnerability and resilience assessment. Once that metrics are identified and then selected on both theoretical and consensus bases, several studies recommend to validate the indicators through a set of criteria that have been mentioned above [START_REF] Cafiero | Validity and reliability of food security measures[END_REF]. Therefore, as it is proposed in this work (see chapter 3) and confirmed in other vulnerability assessments [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF], data will need to be standardized and weights might also be attached to the indicators.

Weight assignment is generally led through expert judgment (deductive arguments) [START_REF] Brooks | The determinants of vulnerability and adaptive capacity at the national level and the implications for adaptation[END_REF][START_REF] Moss | Vulnerability to Climate Change: A Quantitative Approach[END_REF], arbitrary choice of equal weight (normative arguments) [START_REF] Lucas | Vulnerability Concept and its Application to Food Security, National Institute for Public Health and the Environment[END_REF][START_REF] O'brien | Vulnerable or resilient? A multiscale assessment of climate impacts and vulnerability in Norway[END_REF][START_REF] Patnaik | Climate Change and Vulnerability: Evidence from Indian Coastal Districts[END_REF], and statistical methods such as principal component analysis or factor analysis (inductive or non-substantial arguments) [START_REF] Cutter | Social vulnerability to environmental hazards[END_REF][START_REF] Thornton | Climate change and poverty in Africa: Mapping hotspots of vulnerability[END_REF]. Principal component analysis can help generate weights for the selected indicators in agriculture vulnerability assessment [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF] and in spatially-explicit vulnerability assessments [START_REF] Abson | Using Principal Component Analysis for information-rich socio-ecological vulnerability mapping in Southern Africa[END_REF]. In both cited cases the principal component analysis was successfully applied for establishing weights within a set of indicators for different oriented vulnerability indices and allowed spatially differentiating geographical areas with regards to context-specific vulnerabilities; however it was not applied for providing absolute measures of vulnerability or for selecting indicators. The opportunity of mapping social-ecological vulnerability to understand and assess the sustainability of diets and food systems should imply not only indicating which areas al vulnerable, but also identifying to what is driving that vulnerability for informing decision-making. Furthermore, whether the indicator approach, that can use a specific set of indicators as proxy variables to measure vulnerability indices and weighted averages, may be applied at any scale (household, county/district, or national level) [START_REF] Gbetibouo | Vulnerability of the South African farming sector to climate change and variability: An indicator approach[END_REF], choosing the best spatial scale at which to undertake such assessments remains a crucial challenge for further research [START_REF] Abson | Using Principal Component Analysis for information-rich socio-ecological vulnerability mapping in Southern Africa[END_REF].

In this work a subnational level was proposed in order to analyze the vulnerability of a set of common and context-specific food and nutrition security issues vis-à-vis a combination of global and regional drivers of change (see chapter 4). Sub-continental regions are considered a natural spatial level for studies of social-ecological systems (such as food systems) for being often defined by shared cultural, political, economic and biogeographical contexts, contributing to food security research [START_REF] Liverman | Why regions?[END_REF]. This study, therefore, focused on the analysis of vulnerability and resilience of context-specific food system issues at the Mediterranean level (see chapter 1 and 3). Since food and nutrition security issues are based on socialecological interactions, it is necessary to define different scales and levels of analysis that open to regional-level, subregional-level, and cross-level questions [START_REF] Ingram | Undertaking research at the regional level[END_REF]. The specificity of the food and nutrition security issues tackled in this work raised mainly subregional-level and cross-level questions and asked for a smaller geographical focus that was found in the Latin Arc geographical entity (see chapter 4 and 5). Moreover, at a national level, this south-west Mediterranean area of Europe presents levels of population density that are considerably different from other subregions of the Mediterranean Basin, such as the north-west Mediterranean Africa, and in particular several socioeconomic data (as described in chapter 3) show considerable gaps between countries in terms of food and nutrition security related issues (such as the share of DES derived from cereals, adult literacy, child-stunting,wasting, -underweight, global obesity, and overweight). These implications may open further research efforts on the assessment of the sustainability of food systems in other subregions of the Mediterranean, such as North-west Africa, the Middle-East, or the Euro-Mediterranean Balkans, that are likely to be affected by common global and regional drivers of change and sustainability problems (water scarcity, biodiversity loss, etc.) that act on different context-specific food and nutrition issues at a national or subnational level (food preferences, food access, etc.).

Additional elements for further research can be developed building on the framework proposed for analyzing the food system dynamics. In particular the circularity of the food system framework, thus the presence of feedback loops (see above and chapter 4), could be further developed through an advanced specification of the hypotheses that allow identifying the indicators, such as the hypotheses presented in table 7. This could help overcome the risk of linearity of the framework and better define the role of the variables of exposure, sensitivity, and resilience (see figure 4 in chapter 4); it might represent a further contribution aiming at successfully operationalizing the social-ecological systems frameworks and the theories of vulnerability and resilience, for the assessment and understanding of the sustainability problems affecting the food systems, and for identifying the resilience opportunities to support decision-making.

Analyzing the scientific context, the limitations, and the research perspectives of a theoretical approach, a framework, and a selection of indicators for the assessment of sustainable diets and food systems is key to define further research implications.

However, it is paramount to ensure that indicators are useful and have a specific scope, such as satisfying a specific demand or contributing to set up policy actions.

Moreover, it is key to define the real users of the indicators [START_REF] Bell | An analysis of the factors influencing the use of indicators in the European Union[END_REF].

These are crucial and challenging issues to be considered at any further step working on indicators for sustainable food systems.

In conclusion, food systems are systems of variables connected to each other through causal pathways, which are further complexified by operating at different geographical or time scales. It is, therefore, desired to develop interventions that treat the underlying causes, rather than the symptoms of the unsustainability deriving from food systems, and the concepts of vulnerability and resilience can bring food security into consideration in a different way than in the past. Through the vulnerability and resilience theories and approach it is suggested to capture the food system as a whole, think prospectively and identify the system elements that policy can control or There is a growing interest in sustainable diets and food systems. It is marking metrics as an area for research. We believe that your input into the consultative proves for the development of improved metrics will substantially accelerate this much needed work.

The goal of the consultative process is to explore the different approaches to assess the sustainability of our diets, and to build a multidisciplinary task force of experts working on defining shared standards and methods.

We have identified you and your institution as leader in this research. We would like to invite you, through a brief iterative online survey, to select and discuss a first set of indicators. This collaborative process will be further continued at a workshop to be held in Montpellier (France) in the end of 2014, where participants will have the opportunity to share their views and identify commonalities and gaps.

A final report highlighting the recommendations of the panel and acknowledging the contribution of all participants will be published for larger dissemination by Bioversity International and CIHEAM-IAMM.

Our colleagues in charge of this project, Thomas Allen and Paolo Prosperi, will contact you and provide you with more information in the forthcoming days.

We look forward to welcoming you and hope that this will be the beginning of a fruitful joint collaboration on the timely and important topic of Metrics for Sustainable Diets and Food Systems.

Yours sincerely,

Reconsidering Nutrition

Overview

The stark observation of the coexistence of undernutrition, nutrient deficiencies, overweight and obesity the triple burden of malnutritionis inviting us to reconsider health and nutrition as the primary goal of food systems. Agriculture and the food industry have made remarkable advances in the past decades, but have not entirely met health and nutritional needs. Moreover, they have generated unintended consequences including environmental losses. Simultaneously, several regions are experiencing unprecedented weather events caused by climate change and habitat depletion, in turn further destabilizing global food and nutrition security. This confluence of food crises with increasing environmental degradation suggests an urgent need for novel analyses and new paradigms to describe and understand the causes and facilitate adaptation and mitigation.

Participants at the 2010 international conference organized by the FAO and Bioversity International agreed on a common definition of Sustainable Diets that emphasizes the food and nutrition security purpose of food systems, and the need to maintain or enhance this outcome over time -across generations -by preserving essential human and natural assets and the flows of services they provide. The concept of Sustainable Diets promotes economically, socially and environmentally sustainable food systems that concurrently ensure food and nutrition security.

What is counted is what counts: Identifying Metrics

Rationale

Modern societies depend on complex agro-ecological and trading systems to provide food. The move to sustainable diets calls for changes in the agricultural and food systems. Policy-makers and other stakeholders need evidence-based information and assessment tools to lead public policy interventions.

Metrics are an organized information system combined to provide a perspective. It targets three principal objectives: Inform civil society, industry, public officials and all stakeholders Measure progress toward defined goals Aid decision making processes A sound theoretical framework is the starting point in constructing metrics.

More information:

http://www.bioversityinternational.org/research-portfolio/diet-diversity/sustainable-diets/ http://www.iamm.fr/recherche/projets/Indicateurs-de-la-securite-alimentaire-durable-en-Mediterranee

This initiative is funded by:

Suggesting a framework

Framework Sustainabilityor Sustainable Developmentis a necessarily complex concept that can have different understandings. In this exercise, we assume that a sustainability assessment aims at capturing the ability of a system to maintain and enhance its essential functions over time. Sustainability addresses threats to preserving life support systems, including their capacity to withstand and adjust. It is then key to assess stocks of and changes in human and natural assets. Derived from Sustainability sciences, the vulnerability approach, complemented by inputs from the resilience literature, is proposed to analyze the sustainability of critical food and nutrition security outcomes.

Vulnerability -as the degree to which a system is likely to experience harm due to exposure to a perturbation or stress -is a function of:

Exposure: Nature and degree to which a system is likely to be affected by the occurrence of a change; Sensitivity: Degree to which a system is affected, either adversely or beneficially, by a change; Resilience: Ability of a system to anticipate, absorb, accommodate, or recover from the effects of a potentially hazardous event in a timely and efficient manner, through ensuring the preservation, restoration, or improvement of its essential basic structures and functions [START_REF] Ipcc | Managing the risks of extreme events and disasters to advance climate change adaptation: Special report of the intergovernmental panel on climate change[END_REF].

An expert consultation process Delphi survey

The suggested framework and the initial short-list of indicators were developed in discussions with selected expert focus groups. We are now submitting them to a large panel of experts for further discussion. A revised framework and a restricted set of indicators are expected from this consultation process.

Following the protocol of the Delphi Survey, we ask participants to:

Discuss and complement the framework and the underlying assumptions Test the framework by selecting proxy indicators A Delphi Survey is a group interaction process directed in iterative rounds of opinion collection and feedback.

After a first open-ended round, panelists will be presented with the opportunity to justify or amend their first choices. Succeeding rounds are designed to bring the group to focus or consensus.

Suggesting a framework

Framework Sustainabilityor Sustainable Developmentis a necessarily complex concept that can have different understandings. In this exercise, we assume that a sustainability assessment aims at capturing the ability of a system to maintain and enhance its essential functions over time. Sustainability addresses threats to preserving life support systems, including their capacity to withstand and adjust. It is then key to assess stocks of and changes in human and natural assets. Derived from Sustainability sciences, the vulnerability approach, complemented by inputs from the resilience literature, is proposed to analyze the sustainability of critical food and nutrition security outcomes.

Vulnerability -as the degree to which a system is likely to experience harm due to exposure to a perturbation or stress -is a function of: Exposure: Nature and degree to which a system is likely to be affected by the occurrence of a change; Sensitivity: Degree to which a system is affected, either adversely or beneficially, by a change; Resilience: Ability of a system to anticipate, absorb, accommodate, or recover from the effects of a potentially hazardous event in a timely and efficient manner, through ensuring the preservation, restoration, or improvement of its essential basic structures and functions [START_REF] Ipcc | Managing the risks of extreme events and disasters to advance climate change adaptation: Special report of the intergovernmental panel on climate change[END_REF]. Affordability of food refers to the relative cost of feeding oneself. Is assessing the impact of biodiversity loss on the nutritional quality of food supply important? Please rank the level of importance to you. Is assessing the impact of changing food consumption patterns on the nutritional quality of food supply important? Please rank the level of importance to you. Is assessing the impact of food price volatility on the affordability of food important? Please rank the level of importance to you. Using a scale of 1 to 9 (with 1 being the lowest and 9 being the highest), please rate the priority of the following issues with regard to the geographical context.

1
OPEN QUESTIONS

Sustainability and food and nutrition security: An indicator-based vulnerability and resilience approach for the Mediterranean Region

EXTENDED ABSTRACT

BACKGROUND

Recurrent food crises and global change, along with habitat loss and micronutrient deficiencies, placed food security and environmental sustainability at the top of the political agenda. Analyses of the dynamic interlinkages between food consumption patterns and environmental concerns recently received considerable attention from the international community. Socioeconomic and biophysical changes affect the food system functions including food and nutrition security. The sustainability of food system is at risk. Building sustainable food systems has become a key effort to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems involve multiple interactions between human and natural components. The systemic nature of these interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system can help tracking progress towards sustainability and setting policies towards positive transformations.

AIMS

The general objective of this thesis is to analyze and explore the sustainability of the food system through identifying a set of metrics at the Mediterranean region level. The specific aims consist of developing a multidimensional framework to evaluate the sustainability of food systems and diets, identifying the main variables to formalize and operationalize the abstract and multidimensional concept of sustainable food systems, and defining metrics for assessing the sustainability of food systems and diets, at a subregional level.

METHODS

Through a broad understanding of sustainability, the methodological approach of this thesis builds on the theories of vulnerability and resilience. Following the steps of the global change vulnerability assessment a causal factor analysis is presented concerning three Mediterranean countries, namely Spain, France and Italy.

Formulating "what is vulnerable to what" hypotheses, we identified eight causal models of vulnerability. A three-round Delphi survey was then applied to select indicators on the basis of the vulnerability/resilience theoretical framework.

RESULTS

A conceptual hierarchical framework was identified for modeling the complex relationships between food and nutrition security and sustainability for developing potential indicators of sustainable diets and food systems. A feedback-structured framework of the food system formalized eight selected causal models of vulnerability and resilience and identified intrinsic properties of the food system, shaping the interactions where a set of drivers of change (Water depletion; Biodiversity loss; Food price volatility; Changes in food consumption patterns) directly affect food and nutrition security outcomes at a subregional level (Nutritional quality of food supply; Affordability of food; Dietary energy balance; Satisfaction of cultural food preferences). Each interaction was disentangled in exposure, sensitivity and resilience. This theoretical framework was operationalized through the identification of a set of 136 indicators. The Delphi study revealed low, medium, and high consensus and majority level on indicators in 75% of the interactions out of the 24 initial ones. The results obtained in terms of global response, expert participation rates, and consensus on indicators were then satisfactory. Also, experts confirmed with positive feedback the appraisal of the components of the framework.

CONCLUSIONS

This theoretical modeling exercise and the Delphi survey allowed the identification of a first suite of indicators, moving beyond single and subjective evaluation, and reaching consensus on metrics of sustainable diets and food systems for supporting decision-making. The operationalization of the theories of vulnerability and resilience, through an indicator-based approach, can contribute to further analyses on the socioeconomic and biophysical aspects and interlinkages concerning the sustainability of diets and food systems.

Keywords: Food systems, Food Security, Sustainability, Resilience, Mediterranean, Metrics.

  Figure 1:Food system framework…………………………………………..

  Figure 1:Food system framework…………………………………………..

  Figure 2: Vulnerability framework………………………………………….

Figure 3 :

 3 Figure 3: Calculation of Vulnerability……………………………………...

  Figure 4: A causal pathway………………………………………..……..…

Figure 7 :

 7 Figure 7: Structure and pathway of the Delphi study……..……..……..…..

Figure 8 :

 8 Figure 8: Matrix of interactions between global, and regional, drivers of change and context-specific FNS issues……..……..……..……...

Figure 9 :

 9 Figure 9: Share of consensus of the most selected indicator for each of the 24 vulnerability components considered……..……..……..……..

Figure 10 :

 10 Figure 10: Expert appraisal of the eight interactions proposed in the Delphi study for the selection of the indicators……..……..……..……… Figure 11: Expert appraisal of the emerged interactions between the initial set of FNS issues and the newly proposed drivers of change …… Figure 12: Expert appraisal of the initial set of FNS issues and of the newly proposed ones……..……..……..……..……..……..……..………

  UMR 1110 MOISA Montpellier SupAgro & Università di Catania -DiGeSA (Di3A)Sustainability and food and nutrition security: An indicator-based vulnerability and resilience approach for the Mediterranean Region

Figure 2 -

 2 Figure 2 -Vulnerability framework[START_REF] Turner | A framework for vulnerability analysis in sustainability science[END_REF]

  TRANSMANGO is an ongoing EU 4-year research project -under the 7th Framework Programme -that aims at obtaining a comprehensive image of the impacts of the global drivers of change (climate, economic concentration and market structure, financial power, resource competition, marginalization, property rules, geopolitical shifts, consumer preferences, consumption patterns and nutritional transition) on European and global food demand, and on raw material production, and on food flows. The research focuses on the vulnerability and resilience of European food systems in a context of socio-economic, behavioral, technological, institutional and agro-ecological change and aims to improve understanding of the new challenges and

Food

  and nutrition security is a major concern today with still 842 million people undernourished(FAO, 2013a). Resulting undernutrition is affecting millions of people, in particular children under 5 years with about 165 million stunted children in developing countries(UNICEF, 2013).Sub-Saharan Africa and South Asia, with wide subregional variation, are the most affected regions by stunting. Undernutrition is accompanied by, in some cases linked to, micronutrient malnutrition. Malnutrition involves privation in essential micronutrients with low food diversity. Deficiencies in essential micronutrients have detrimental effects on health; vitamin A is required for multiple physiological processes, ranging from vision to embryonic development; iron is an important component of hemoglobin, the oxygen carrying component of blood; iron also plays an important role in brain development and iron-deficiency anemia can impair the cognitive development of children; iodine is essential for healthy thyroid function and growth, etc. Simultaneously, increased prevalence of overweight and obesity are reported in both low-and high-income countries and represent the major health threats. Excessive fat accumulation, measured by the BMI, is acknowledged to be a risk factor for various non-communicable diseases and health problems, including CVD, diabetes, cancers and osteoarthritis(WHO, 2014). Simultaneously, climate change and environmental degradation are major challenges to sustainable development.

  [START_REF] Holzkämper | A generic tool for optimising land-use patterns and landscape structures[END_REF] developed a spatially explicit optimization model with respect to ecological and economic goals, namely habitat suitability for three target species and profit losses from different land-use options. Results show that optimum agricultural land-use patterns differ between species, as well as between study sites.[START_REF] Groot | Exploring multi-scale trade-offs between nature conservation, agricultural profits and landscape quality-a methodology to support discussions on land-use perspectives[END_REF] explore the synergies and trade-offs between financial returns, landscape quality, nature conservation and environmental quality in a spatially explicit land-use allocation model, which combines agronomic, economic and environmental indicators with biodiversity and landscape quality indicators. More specifically, their Landscape IMAGES model couples an agroecological model to a multi-objective optimization algorithm that generates a set of alternative landscape configurations. An agroecological engineering approach was used to design production activities. Alternatively, impacts on biodiversity of different land-use management options and policy scenario can be assessed through optimization models. Schönhart et al. (2011) address the effects of land use intensity and landscape development on biodiversity at farm and landscape levels. Their integrated land use model combines a crop rotation model with a biophysical process model (erosion-productivity impact calculator) and a spatially explicit farm optimization model. Field-and farm-specific crop yields, crop rotations and environmental outcomes of the biophysical model are inputs to the farm optimization model, which maximizes total farm gross margin subject to resource endowments and several balance equations.Decisions in integrated land use model are assumed to reflect actual producers' choices postulating efficient farm resource utilization. This structure allows introducing landscape metrics, such as the Shannon's diversity index, to quantify the spatial biodiversity impacts of landscape development scenarios. Scenario analysis is used to assess the cost-effectiveness of different agro-environmental measures to achieve biodiversity targets. One asset of the integrated land use models is the inclusion of spatial modeling of landscape elements. Similarly,[START_REF] Mouysset | Bio-economic modeling for a sustainable management of biodiversity in agricultural lands[END_REF] adopt a multi-criteria approach to assess jointly the impacts of public policy options on conservation of biodiversity and farming production. Assuming incomemaximizing farmers under technical constraints, the authors test different taxation scenarios on economic performances and farmland bird abundance.

  of food insecurity and environmental unsustainability is strictly linked to the identification of a methodological framework functioning as an architectural net. In[START_REF] Rastoin | Vulnérabilité régionale à l'ouverture commerciale internationale: le cas des fruits et légumes dans l'Euro-Méditerranée[END_REF],Cinner et al. (2011),[START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF], as in the vulnerability composite index of food insecurity in[START_REF] Manarolla | A methodology for ranking countries according to relative food insecurity[END_REF], vulnerability is calculated through multidimensional score systems. The vulnerability causal framework is modeled through three dimensions: exposure, sensitivity and adaptive capacity.

  Cinner et al. (2011) and[START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF] calculate vulnerability as Exposure + Sensitivity -Adaptive Capacity (Figure 3). Lower levels of the final score indicate lower level of vulnerability. Following the original structure designed by Hughes et al. (2012), keeping the same logical sequence of signs, Figure 3 outlines several n vulnerabilities. This specification of n different vulnerabilities of different issues to different drivers of change, aims to capture the multidimensional feature of sustainability.

Figure 3

 3 Figure 3 Calculation of Vulnerability (Adapted from[START_REF] Hughes | A framework to assess national level vulnerability from the perspective of food security: The case of coral reef fisheries[END_REF]

  pertinent question can be: To which extent are the Mediterranean countries vulnerable to climate change in order to supply sufficient food commodities?Given the crucial issue around water supply in the Mediterranean region, geographical indicators of the availability and quality of water can be considered a relevant measure of the exposure of a national (or a sub-national) food system to climate change in terms of provisioning of food. Consequently, sensitivity to this exposure can be expressed according to the specific level of consumption of waterdemanding commodities by the households or the agro-industry. In response, agrobiodiversity could be an indicator of adaptive capacity to climate change, based on the assumption that biodiversity increases the stocks of crop material to draw upon to select or develop more drought-resistant crops. Ability to import from less exposed agricultural systems to climate change might be another indication of adaptive capacity.Food accessibility-related vulnerability to international price volatility.Food accessibility involves both physical access and affordability for individuals to adequate resource of food. A research question that emerges can be the following: To which extent are the Mediterranean countries vulnerable, considering their economic constraints, biophysical conditions and social habits, in their access to adequate food in the face of high price volatility? Given the high cereal import dependency of some Mediterranean countries (for human consumption, industry demand and animal feeding), exposure could be assessed by considering the caloric share of cereals in a representative household's food basket: The more cereals consumed, the higher the exposure for import-dependent countries. Price elasticities for cereals might offer a proxy for countries' sensitivity to fluctuating international cereal prices. Conversely, analyzing food consumption patterns, and households' capacity to shift towards cheaper or locally available food, while meeting the same caloric and nutritional requirements, may indicate strong adaptive capacities. Cross-price elasticities illustrate substitution possibilities. Countries can enhance this adaptive capacity by implementing food policies that diversify supply sources, by acting directly on food prices (e.g. subsidies), by providing social nets for the population (e.g. food stamps) or promoting diversity in consumption patterns.Nutritional quality-related vulnerability to nutritional transition and changing consumption patterns.Utilization encompasses all the factors related to how food is consumed and involves quality elements. In a nutrition-driven approach we consider also nutritional values of foods and adequacy of diets to nutrient recommendations. Therefore, the research question in our specific context can be the following: In which way and to which extent are the Mediterranean countries vulnerable, considering nutritional value and nutrient adequacy, to nutritional transition and changing consumption patterns?Over the past fifty years the Mediterranean region has undergone important structural demographic and spatial transformations with an increasing share of its population now located in urban centers. Urbanization trends can be suggested as a proxy for exposure to changing food consumption habits, on the assumption that urban and rural consumption patterns are significantly different. Correlated with urbanization, industry and labor structures can be selected to indicate to which extent Mediterranean countries are exposed to nutritional transition. Subsequently, countries and populations manifest sensitivity to these exposures with critical data on the prevalence of health problems directly related to diet, such as obesity or cardiovascular diseases. Governments, policymakers and individuals can implement a set of tools to enhance adaptive capacity, such as ensuring an efficient health system, improving education and promoting food and healthy eating and lifestyle habits, guiding consumption patterns, and raising awareness on these issues within institutions and the private sector.

France

  enhanced over time, across generations, can help organizations and governmental institutions track progress towards sustainability and set policies that encourage positive transformations. This chapter proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socioeconomic changes, postulating specific food and nutrition security issues as priority food systems' outcomes. Acknowledging the systemic dimension of sustainability, the approach allows considering causal factors dynamics. In a stepwise approach, a logical application is schematized to three Mediterranean countries, namely Spain, a guiding principle and main goal for human development.Environmental degradation, social distress and economic fluctuation are worldwide concerns challenging conventional views on development and forcing reconsideration of our everyday behaviors. Rapid climate change has been occurring for the past few decades, and is predicted to continue and possibly accelerate[START_REF] Ipcc | Summary for Policymakers[END_REF]. Global biodiversity is declining, with substantial ongoing losses of populations, species and habitats (UNEP, 2012). Increasing land clearance for crop cultivation has been leading to habitat loss and may ultimately result in the loss of plant varieties. Policy needs to strengthen the perception of humanity and nature as interdependent and interacting. This requires revisiting our policies and behaviors, and developing adaptive management approaches acknowledging the systemic and dynamic nature of current changes.

Food

  and nutrition security remains a crucial policy issue in every country and the current global crisis of malnutrition is an urgent concern both in developed and developing countries. The proponents of the "Sustainable Diets" agenda -a closely related concept highlighting the role of consumers in defining sustainable optionsprovide in particular a food and nutrition security-orientated perspective on the question of the sustainability of food systems(FAO & Bioversity, 2012;[START_REF] Johnston | Understanding sustainable diets: a descriptive analysis of the determinants and processes that influence diets and their impact on health, food security, and environmental sustainability[END_REF]. Transforming the abstract concept of sustainability into descriptive objectives, this chapter proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socio-economic changes in the Mediterranean region, postulating specific food and nutrition security issues as priority food systems' outcomes. Identifying and modeling the intrinsic

Figure 4 -

 4 Figure 4 -A causal pathway (Adapted from Fussel &Klein, 2006)

Figure 5 -

 5 Figure5-Basic representation of a dynamic system (adapted from[START_REF] Rastoin | Le système alimentaire mondial: concepts et méthodes, analyses et dynamiques[END_REF]

  involves answering the question "vulnerability/resilience of what to what". It requires identifying the main drivers of change simultaneously as the food system-specific issues of concern that the drivers are likely to affect(Schroeter et al., 2005). Several global and regional drivers of change affect the structure and processes of the food systems, putting at risk context-specific food and nutrition security outcomes. Based on an extensive literature review and discussions conducted over two focus groups gathering a group of seven experts, four critical food and nutrition security issues and four drivers of change have been identified at a sub-regional level. An exhaustive and rigorous literature review, specific for the Mediterranean region, highlighted existing urgent issues and crucial drivers of change(CIHEAM, 2012;[START_REF] Scar | Foresight Exercise: New challenges for Agricultural Research: Climate change, food security, rural development, agricultural knowledge systems[END_REF][START_REF] Parme | Quelles recherches et quels partenariats pour la Méditerranée?[END_REF]. The selected four main drivers of change are the following:

Food

  choices are deeply embedded in social norms. Individual food consumption patterns -i.e. diets -are the results of changes in culture, social values and representations attached to food consumption, driving effectively behavioral changes and resulting in modified diets. The global changes in food consumption patternssome talk about a "westernization" of food consumption patterns (Drewnowski & Popkin, 1997) -are largely driven by demographic factors and income growth, and related to changes in dominant values and lifestyle, influenced by globalization, urbanization, changes in occupational status and employment distribution, and more effective dissemination of information[START_REF] Meade | Global Food Markets[END_REF].

  Conceptual frameworks for indicators allow focusing and defining what to measure, what solutions and findings to gain from the assessment and what kinds of metrics to apply. Different frameworks have been developed for the assessment of sustainability because of different conceptual approaches and views, and different research goals. However, the key differences among different frameworks reside in the interpretations of the dimensions of sustainable development, the interconnections between these dimensions, the structural organization and the concepts by which they justify the hypotheses for the selection and aggregation of the indicators (UN, 2007).

  indicators can provide a detailed description of observable variables, or interactions of variables, relevant to the food and nutrition security. The selection of indicators is a crucial step and need to be realized beyond individual subjectivity and single value judgments. Once that a framework defines the phenomenon to be measured, ideally the selection of the individual indicators should be based on what is desirable to measure and not on which indicators are available. Furthermore, the transparency of the whole exercise is essential in constructing credible indicators (OECD, 2008).

Figure 7 -

 7 Figure 7 -Structure and pathway of the Delphi study

Figure 8 -

 8 Figure 8 -Matrix of interactions between global, and regional, drivers of change and context-specific food and nutrition security issues (adapted from Prosperi et al., 2014; see chapter 4)

(

  25%); Policies (including Agri/Energy/Rural/Trade/Food policies) (25%); ) (11%); World population (including Migration flows) (9%); Soil degradation (7%); Global economy trends (including Income distribution) (6%); Climate change (5%); Energy prices (4%). As regards additional potential drivers affecting the nutritional quality of food supply, participants highlighted the importance of considering potential impacts from Technological innovation and Soil degradation (24% and 17% respectively). Climate change, Policies and Agrifood patterns (i.e. agrofood industry and market structure) are the second most quoted drivers, with around 10% of the proposals.

Figure 10 -

 10 Figure 10 -Expert appraisal of the eight interactions proposed in the Delphi study for the selection of the indicators

Figure 11 -

 11 Figure 11 -Expert appraisal of the emerged interactions between the initial set of food and nutrition security issues and the newly proposed drivers of change

  but also the rate of participation in relation with the initially invited experts can sensitively vary. In a recent Delphi study -aimed at the identification of drivers, pressures, and indicators of the environmental impacts on the Galapagos Islands (Benitez-Capistros et al., 2014) -42 participants were initially invited, only 10 (24%) actually participated in the first round and 5 responded to the third and final round. In another Delphi study -focused on finding an agreement on a definition of climate change adaptation (de Franca Doria et al., 2009) -38 experts were invited and 23

  Furthermore, whether this selection of indicators provided acceptable results in terms of consensus and further perspectives for research, quantitative aspects still represents a limiting factor for several indicators in view of potential application. In fact data availability is usually one of the key criteria to consider in the selection of indicators and in the identification of composite indicators. However, in this Delphi study, several indicators that are not yet measured gain in interest and consensus. Indeed, searching for appropriate metrics implies to go through what is desirable to measure and not which indicators are available (OECD, 2008). These findings might suggest that some of the indicators reaching consensus -that are not yet measured -are

  Indicators are the indicating variables that allow the operationalization of the theoretical concept of vulnerability and resilience through the methodology of vulnerability assessment. Building on[START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF], for identifying vulnerability indicators three kinds of substantial arguments are available and they are defined namely as deductive, inductive, normative, and non-substantial ones. Inductive arguments are based on using data for building statistical models. Normative arguments build on value judgments in the selection and aggregation of indicating variables. Non-substantial arguments are based only on the data structure of the indicating variables and do not imply knowledge about vulnerability, nor on value judgments. Differently, deductive arguments consist of using available scientific knowledge in form of frameworks, theories or models about the vulnerable system of interest in the selection and aggregation of indicating variables, and imply also expert judgment argument, that is considered a weak approach[START_REF] Hinkel | Indicators of vulnerability and adaptive capacity": Towards a clarification of the science-policy interface[END_REF]. Since this work strongly builds on the operationalization of the theories of vulnerability and resilience, within the social-ecological system framework, through an expert-based selection of metrics of the sustainability of the food systems it is possible to classify this research effort within the group of deductive arguments for developing vulnerability and resilience indicators. Normative arguments also imply using individual or collective value judgments. It is, therefore, unclear whether expert value judgments have to be classified, according toHinkel's classification (2011), within

  so there are not yet quantitative means to test them -on the other hand this is also one of the purposes of the expert elicitation: to open the understanding, reflection and debate, and let experts freely propose innovative solutions. Then, there might be a subsequent call for measuring specific indicators that are not yet assessed.

  mitigate. The distinction in three components, namely exposure, sensitivity and resilience, provides the elements of a model that specify what attributes need to be measured and how to structure the different indicators in a coherent assessment framework for improved decision-making and policies. The design of legitimate and collective decision processes is then crucial to sustainability. Thomas Allen: t.allen@cgiar.org Paolo Prosperi: prosperi@iamm.fr Bioversity International, Via de Tre Denari, 472/a, 00057 Maccarese, Rome, Italy CIHEAM-IAMM, 3191, route de Mende, 34093, Montpellier, France This initiative is funded by: CIHEAM-IAMM have the pleasure to invite you to participate in the expert consultation survey Metrics of Sustainable Diets and Food Systems 2014.

Objectives 1 .

 1 This brief has been prepared by: Thomas ALLEN (Bioversity International) and Paolo PROSPERI (CIHEAM-IAMM) This initiative is endorsed by: Exploring the different approaches to assess the sustainability of Diets and Food Systems 2 . Establishing a multidisciplinary taskforce of experts 3 . Identifying a shortlist of indicators for Sustainable Diets and Food Systems Initial focus on Spain, France and Italy 3 Mediterranean countries facing similar food and nutrition security issues and exposed to common global and regional drivers of change

  Vulnerability/Resilience of what to what? Main Facts Increasing consumption of nutrient-poor energydense foods and beverages Widespread obesity and overweight: France 46%, Italy 49%, Spain 58% among adults (WHO, 2013) Rising food cost especially in nutrient-rich and diverse foods, and increasing poverty Water demand doubled in 50 years in Mediterranean countries (UNEP, 2006) Declining biodiversity in the Mediterranean with 19% of the species threatened (IUCN, 2008) An ongoing dietary transition coupled with changing life and consumption patterns Several global and regional drivers of change affect the structure and processes of the food systems, putting at risk context-specific food and nutrition security outcomes. Based on an extensive literature review, 4 critical food and nutrition security issues and 4 drivers of change have been identified:

-

  regards affordability of food, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with water depletion? If unsatisfied by the selection, please suggest other indicators: FOOD PRICE VOLATILITY 7. As regards affordability of food, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with impact of water depletion on the nutritional quality of food supply important? Please rank the level of importance to you. -If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below:

-

  If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below:FOOD PRICE VOLATILITY 3. As regards nutritional quality (of food supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with food price volatility?Please find below the results from the first round. Decide whether to confirm or amend your first choices. Individual feedback -with first round choices -is provided in the pdf file attached to the last email you received. impact of food price volatility on the nutritional quality of food supply important? Please rank the level of importance to you.-If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below: regards nutritional quality (of food supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with changing food consumption patterns?Please find below the results from the first round. Decide whether to confirm or amend your first choices. Individual feedback -with first round choices -is provided in the pdf file attached to the last email you received.-

-

  If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below: 5. Several participants have proposed two other drivers of change likely to impact the NUTRITIONAL QUALITY OF FOOD SUPPLY. Please rank each driver according to importance. refers to the relative cost of feeding oneself.WATER DEPLETION 6. As regards affordability of food, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with water depletion?Please find below the results from the first round. Decide whether to confirm or amend your first choices. Individual feedback -with first round choices -is provided in the pdf file attached to the last email you received.impact of water depletion on the affordability of food important? Please rank the level of importance to you.-If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below: regards affordability of food, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with food price volatility?Please find below the results from the first round. Decide whether to confirm or amend your first choices. Individual feedback -with first round choices -is provided in the pdf file attached to the last email you received.-

-

  If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below: 8. Several participants have proposed two other drivers of change likely to impact the AFFORDABILITY OF FOOD. Please rank each driver according to importance. and market patterns Dietary energy balance refers to the balance between energy intake and energy expenditure. CHANGING FOOD CONSUMPTION PATTERNS 9. As regards dietary energy balance, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with changing food consumption patterns?Please find below the results from the first round. Decide whether to confirm or amend your first choices. Individual feedback -with first round choices -is provided in the pdf file attached to the last email you received.impact of changing food consumption patterns on the dietary energy balance important? Please rank the level of importance to you. -If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below: participants have proposed two other drivers of change likely to impact the DIETARY ENERGY BALANCE. Please rank each driver according to importance. impact of biodiversity loss on the satisfaction of cultural food preferences important? Please rank the level of importance to you. -If you wish, you can explain your choice [as regards the level of importance you attributed to the interaction] in the comment box below: participants have proposed two other drivers of change likely to impact the SATISFACTION OF CULTURAL FOOD PREFERENCES. Please rank each driver according to importance. and market patterns A Delphi Expert Consultation -Round 3 RESILIENCE -If you wish, you can explain your choices or comment the indicators in the box below: CHANGING FOOD CONSUMPTION PATTERNS 4. As regards nutritional quality (of food supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with changing food consumption patterns?Please find below the results from the second round. Decide whether to confirm or amend your previous choices. Individual feedback -with YOUR second round choices -is provided in the pdf file attached to the last email you received.the menu] A Delphi Expert Consultation -Round 3 Affordability of food refers to the relative cost of feeding oneself. WATER DEPLETION 5. As regards affordability of food, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with water depletion? Please find below the results from the second round. Decide whether to confirm or amend your previous choices. Individual feedback -with YOUR second round choices -is provided in the pdf file attached to the last email you received. -the menu] A Delphi Expert Consultation -Round 3 Dietary energy balance refers to the balance between energy intake and energy expenditure. CHANGING FOOD CONSUMPTION PATTERNS 7. As regards dietary energy balance, what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with changing food consumption patterns? Please find below the results from the second round. Decide whether to confirm or amend your previous choices. Individual feedback -with YOUR second round choices -is provided in the pdf file attached to the last email you received. -the menu] A Delphi Expert Consultation -Round 3 9. Four Food & Nutrition Security issues, specific to the geographical context considered (Spain, France and Italy), have been identified within the framework. Five new issues have been suggested by participants (see section E in the 'yourname_INDI_R3.pdf' file attached).

Table 2 :

 2 Interactions Drivers of change / FNS Issues……..……..………..

Table 3 :

 3 Global response and participation rates……..……..……..………

Table 4 :

 4 Participation rate by composition of the panel……..……..……...

Table 5 :

 5 Consensus rate of the most selected indicator/s per vulnerability component in the three Delphi rounds……..……..……..………..

Table 6 :

 6 Participation rate and degree of variation of the Delphi disciplinary groups over the three rounds……..……..……..…….

Table 7 :

 7 Analytical

details of the formulation of the most selected indicators……..……..……..……..……..……..……..……..……..

Table 8 :

 8 Appraisal of Food and Nutrition Security issues for Economists

and Nutritionists' groups by Standard Deviation……..……..…….

  . In particular, the Joint Research Centre, with the CIHEAM-IAMM and other partners, further developed the FSSIM model of the European Commission for application in developing countries.

	The FSSIM-Dev (Farm System Simulator for Developing Countries) model is a bio-
	economic farm household optimization model, with a first application to Sierra Leone
	(Louhichi et al., 2013). A household module has been added to the modular structure

of FSSIM. Production, and related environmental outcomes, as well as food consumption are outputs of the model. Conditionally on the quality of the data about the environmental impacts associated with each production activity, and about food consumption and associated nutritional intakes entered and generated out of the model, such a model could assess the farming practices best suited to improve different sets of nutrition and/or biodiversity indicators and the associated trade-offs.

  . They allow exploring key processes and outcomes of the analyzed systems for food and nutrition security, delivering innovative and deeper insights at the environmental level. Food consumption behaviors play a central role in driving us towards the sustainable food system.Recurrent food crises and climate change, along with habitat loss and micronutrient deficiencies are global issues of critical importance that have pushed food security and environmental sustainability to the top of the political agenda. Analyses of the dynamic linkages between food consumption patterns and environmental concerns have recently received considerable attention from the international and scientific community. Using the lens of a broad sustainability approach, this chapter aims at developing a multidimensional framework to evaluate the sustainability of food systems and diets, applicable to countries of the Mediterranean region. Derived from

	Preface to Chapter 3 Chapter 3
	Sustainability and Food & Nutrition Security: A
	Understanding how food supply translates in nutrition-adequate consumption patterns, Vulnerability Assessment Framework for the
	together with capturing choice determinants and underlying consumer's perceptions of environment-friendly practices, are crucial to help guide changes towards Mediterranean Region 2
	sustainable uses of resources for nutrition. Food consumption behavior has not

attracted enough attention from the sustainability community. Further research requires knowledge of the concepts and insights from a wide range of disciplines to tackle the complexity and diversity of influences at work in food choices. Joint efforts are needed in addressing food and nutrition security through a multidisciplinary and multisectoral approach to social-ecological systems.

natural disaster and sustainability sciences, a vulnerability approach, enhanced by inputs from the resilience literature, has been adapted to analyze the main issues related to food and nutrition security. Through causal factor analysis, the resulting conceptual framework improves the design of information systems or metrics assessing the interrelated environmental, economic, social and health dynamics of food systems.

2 This chapter is adapted from: Prosperi, P.,

[START_REF] Prosperi | Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region[END_REF]

. Sustainability and Food & Nutrition Security: A Vulnerability Assessment Framework for the Mediterranean Region. SAGE Open, 4(2).

  On the supply side, all the dietary energy supplies (DES) of the Mediterranean countries 6 largely exceed the average dietary energy requirements. At the same time the majority of these countries are strongly dependent on imports, especially for cereals (except France and Turkey). Furthermore, the share of DES derived from

	cereals is still considerably high (Egypt 65%, Morocco 57%, Algeria 55%, Tunisia
	51%, Libya 49%, Turkey 48%) (FAOSTAT 2009, data available in November 2013) 7 .
	This cereal-centered dependency can lead to a regional and national vulnerability. In
	particular, it occurs at the expense of middle-and low-income groups, and of the
	national government expenditure. For example, bread subsidies, amounting to US$
	Egypt 18‰, Tunisia 14‰, Albania 13‰, Turkey 12‰), child stunting (Egypt 31%,
	Syria 27%, Albania 23%, Morocco 23%, Libya 21%, Algeria 16%, Tunisia 9%),
	wasting (Morocco 11%, Syria 11%, Albania 9%, Egypt 8%, Libya 6%, Algeria 4%,
	Tunisia 3%) and underweight (Morocco 10%, Syria 10%, Egypt 7%, Albania 6%,
	Libya 6%, Algeria 4%, Tunisia 3%) are still considerably high (WHO, data available
	in November 2013). In addition to this, obesity and overweight are growing problems
	common to all the Mediterranean countries, both for adults and children. This double
	burden of malnutrition is manifest in Egypt with prevalence rates of 33% in adult
	obesity and 20% for child overweight, against 31% for child stunting. Overweight and
	obesity are also risk factors in cardiovascular diseases, which contribute to 42% of all
	This count involves overweight and underweight adults (age > 20 years) and overweight, deaths in the Mediterranean
	underweight, stunted and wasted children (age < 5 years) within the Mediterranean population.
	Available data at September 2013 were collected from: World Health Organization, Global Database
	on Child Growth and Malnutrition and Global Database on Body Mass Index; UN Department of
	Economic and Social Affairs -Population Division).

3 Data is not completely available for all Mediterranean countries.

4 5

In UN databases many of the cited statistics are not assessed in several Mediterranean countries: Child stunting, wasting and underweight are not assessed in Cyprus, France, Greece, Israel, Italy, Lebanon, Malta, Portugal, Slovenia and Spain; Child wasting is not assessed in Algeria, Croatia, Morocco, and Turkey. Child stunting is not assessed in Turkey; Child overweight is not assessed in Croatia, Cyprus, France, Israel, Italy, Malta, Portugal and Serbia; Adults underweight is assessed just in France, Italy, Jordan, Malta, Portugal, Spain, Macedonia and Turkey. Adults' overweight is assessed in all Mediterranean countries.

2.5 billion per year, were introduced in Egypt in 2008

[START_REF] Ciheam | Towards the development of guidelines for improving the sustainability of diets and food consumption patterns: the Mediterranean Diet as a pilot study[END_REF]

. It is also necessary to consider food price volatility, in particular for cereals, as it affects consumers' capabilities to access food. Other related socio-economic factors also determine access to food, such as adult literacy, which is still low in some countries (Libya 89%, Algeria 73%, Egypt 72%, Morocco 56%) (UNESCO, data available in November 2013). As for the utilization dimension of food security, nutritional value and food safety remain critical issues. Infant mortality (Morocco 28‰, Algeria 26‰,

Table 1

 1 Advantages of a vulnerability approach

Table 2 -

 2 Interactions Drivers of change/FNS Issues

		Food and Nutrition Security Issues	References
	Drivers of change	Nutritional quality of food supply
	FOOD PRICE VOLATILITY

•

  Shifting the demand towards cereals, simple sugars, animal products and highly processed foods.

			(European Technology Platform,
			2008; Brunori & Guarino, 2010;
			SCAR, 2011; UNEP, 2012;
			Prosperi et al 2014; WHO, 2014)
		• Improving the understanding of the determinants of
	Recovery potential	consumer choices. • Empowering consumers' choice for healthy and safe provided food.	(SCAR, 2011; Khoury et al., 2014; Allen et al., 2014)
		• Engendering consumption patterns cognizant of the
		impact of food choice on health.

Table 3 -

 3 Global response and participation rates

Table 4 -

 4 Participation rate by composition of the panel (from invitation to the final round)

Table 6 -

 6 Participation rate and degree of variation of the Delphi disciplinary groups over the three rounds

	Agronomy
	Ecology / Environmental resources
	Economics
	Food security/policy
	Food systems
	Food tech
	Statistics
	Sustainability	4%

Table 7 -

 7 Analytical details of the formulation of the most selected indicators

  Oneexpert wondered if "biodiversity[was] related with the number of foods favourable to nutrition? The selection of adequate plants or livestocks[sic], for example costless in water and with a good nutrients value, may be more efficient for sustainability". On the contrary, other experts explicitly highlighted that "both domestic and wild biodiversity" and "intraspecific variation in nutrient content across varieties[are] extremely important" for nutritious food supply and healthy diets, an expert adding that "(...) plant variety breeding is going too far and in the wrong direction (...)". An expert stressed the need to distinguish biodiversity and agrobiodiversity, and questioned whether "separate indicators" were required. It has to be reported that Climate change, proposed by 5% of the respondents in the first round, has been highlighted again in the open ended questions as an important driver to consider per se, in addition to Water depletion and Biodiversity loss.

Table 8 -

 8 Appraisal of Food and Nutrition Security issues for Economists and Nutritionists' groups by Average Deviation

  Environment of the University of Catania works, at national and international level, especially on the Mediterranean countries, and the UMR Moïsa-Montpellier SupAgro's geographical area of study covers various regions of the world, with a central focus on France and the Mediterranean. Spain, Italy, and France are border countries, contouring the same biogeographical region of the Mediterranean, and are all country members of the European Union and OECD, presenting relatively similar socioeconomic and policy-related aspects and characteristics.However, these three countries have different features at a more specific level. The northern, continental and Atlantic areas of France are commonly not considered part of the biogeophysical Mediterranean region. Also, the Atlantic regions of Spain are not included in the Mediterranean area. Italy is rather considered a Mediterranean

	country, still presenting a considerably vast Alpine and continental area (Natura
	2000).
	The Latin Arc sub-region proposed, therefore, as it has already been suggested to be
	an interesting area for research in local cooperation at a regional, European and
	transnational level in the aforementioned European research projects (Western
	Mediterranean and Latin Alps, INTERREG II C Programme, EU: ESPON, 2010;
	Camagni and Capello, 2011; see pages 112-113 of this document), was identified also
	as a potential focus area that can both fulfill specific scientific research needs and
	institutional targets.
	, was
	driven by both institutional and research reasons. This thesis, in fact, is closely related
	to the research project "Metrics of Sustainable Diets and Food Systems", which is
	jointly implemented by Bioversity International-CGIAR (Nutrition and Marketing
	Diversity Programme -Italy and France) and CIHEAM-IAMM (France). In the
	meantime, this thesis is supervised by the Department of Agriculture, Food and
	Environment of the University of Catania (Italy), and the UMR Moïsa-Montpellier
	SupAgro (France). All these institutions lead scientific research in various
	geographical areas, including the Mediterranean Region. CIHEAM-IAMM is an
	international center of research on agrofood issues working essentially on the whole
	Mediterranean area. Bioversity International's initial institutional focus, for this
	project, was on France and Spain. The Department of Agriculture, Food and

  food systems, starting from the expert consultation results that call for a deeper analysis of environmental externalities and social equity, as well as food safety and governance issues, and their potential interactions with current drivers of change such as technological innovation, policy actions, or changing agrofood patterns and structures.With regards to the availability of data, according to the list of 15 selected indicators presenting low, medium, and high consensus, at least 9 of them are not computed in the geographical area considered. In fact, experts were let free to choose for indicators without being influenced by the availability of data. Furthermore, since searching for appropriate metrics implies to go through what is desirable to measure and not which indicators are available(OECD, 2008), this might encourage further retrieval of data for these indicators, in order to assess the drivers, issues, and the related interactions proposed that are not yet measured.

(see chapter 5), the framework proposed is a dynamic structure that is open to further applications and integration with different drivers and issues. New research could originate from this framework and investigate further sustainability challenges for the

  Technical Brief 1.0-2014 12 March 2014 Identifying appropriate Metrics of Sustainable Diets and Food Systems

  BIODIVERSITY LOSS 2. As regards nutritional quality (of supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with biodiversity loss? If unsatisfied by the selection, please suggest other indicators: FOOD PRICE VOLATILITY 3. As regards nutritional quality (of supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with food price volatility? If unsatisfied by the selection, please suggest other indicators: CHANGE IN FOOD CONSUMPTION PATTERNS 4. As regards nutritional quality (of supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with changing food consumption patterns? If unsatisfied by the selection, please suggest other indicators:

		EXPOSURE:
		SENSITIVITY:
		RESILIENCE:
	*
			EXPOSURE	SENSITIVITY	RESILIENCE
	[select from the menu]
		EXPOSURE:	EXPOSURE	SENSITIVITY	RESILIENCE
	[select from the menu]
		SENSITIVITY:
		RESILIENCE:
	*	EXPOSURE: SENSITIVITY:
		RESILIENCE:	EXPOSURE	SENSITIVITY	RESILIENCE
	[select from the menu]
	*
		EXPOSURE:	EXPOSURE	SENSITIVITY	RESILIENCE
	[select from the menu]
		SENSITIVITY:
		RESILIENCE:

. As regards nutritional quality (of supply), what indicator would best proxy the EXPOSURE/SENSITIVITY/RESILIENCE of a food system confronted with water depletion? -If unsatisfied by the selection, please suggest other indicators: -NUTRITIONAL QUALITY OF FOOD SUPPLY * --

UMR 1110 MOISA Montpellier Supagro & Universitå di Catania -DiGeSA (Di3A) PhD Thesis in Agrofood Economics Mesures de la sécurité alimentaire et de l'alimentation durable en Méditerranée, basées sur les approches de la vulnérabilité et de la résilience. RÉSUMÉ DÉTAILLÉ CONTEXTE

  Les crises alimentaires récurrentes, les changements globaux, l'épuisement des ressources naturelles et les carences alimentaires en micronutriments placent la sécurité alimentaire et la durabilité environnementale au centre de l'agenda politique. Les analyses des interactions dynamiques entre les modes de consommation et les préoccupations environnementales ont reçu une attention considérable. Les changements socioéconomiques et biophysiques affectent les fonctions du système alimentaire, y compris la sécurité alimentaire et nutritionnelle. Ainsi, la durabilité du système alimentaire est menacée. La construction de systèmes alimentaires durables est devenue un effort majeur pour réorienter les systèmes et les politiques alimentaires vers des objectifs adaptés et vers l'amélioration du bien-être sociétal. L'identification et la modélisation des propriétés intrinsèques du système alimentaire peuvent contribuer à suivre les progrès accomplis vers la durabilité, et participer à la mise en place de politiques de transformation et d'innovation. OBJECTIFS L'objectif général de cette thèse est d'analyser la durabilité du système alimentaire à travers l'identification d'un ensemble d'indicateurs dans la région méditerranéenne. Spécifiquement il s'agit de développer un cadre multidimensionnel pour évaluer la durabilité des systèmes alimentaires, d'identifier les principales variables pour formaliser et opérationnaliser le concept abstrait et multidimensionnel des systèmes alimentaires durables, et de définir une série d'indicateurs pour évaluer la durabilité des systèmes à un niveau sous-régional.APPROCHE MÉTHODOLOGIQUEA travers une approche de la durabilité dans son sens large, la démarche méthodologique s'appuie sur les théories de la vulnérabilité et de la résilience. Suivant les étapes de l'évaluation de la vulnérabilité aux changements globaux, une analyse causale a été présentée à une échelle géographique concernant trois pays méditerranéens: l'Espagne, la France et l'Italie. Huit modèles causaux de la vulnérabilité ont été identifiés. Une enquête Delphi a ensuite été menée pour sélectionner les indicateurs.RÉSULTATSUn cadre conceptuel hiérarchique a été identifié pour modéliser les relations complexes entre la sécurité alimentaire et nutritionnelle et la durabilité. Il a ainsi été possible de formaliser huit modèles causaux de la vulnérabilité et de la résilience. Outre cela, les propriétés intrinsèques du système alimentaire qui modélisent les interactions directes entre les facteurs de changement (l'épuisement des ressources en eau; la perte de la biodiversité; la volatilité des prix; les changements dans les modes de consommation) et les enjeux de la sécurité alimentaire et nutritionnelle au niveau sous-régional (la qualité nutritionnelle de l'approvisionnement; l'accès économique, l'équilibre énergétique; la satisfaction des préférences) ont pu être identifiées. Chaque interaction a été déclinée en exposition, sensibilité et résilience. Ce cadre théorique a été opérationnalisé par l'identification d'une série de 136 indicateurs. L'étude Delphi a révélé des consensus de niveau majoritaire, faible, modéré ou fort sur les indicateurs dans 75% des interactions. Les résultats obtenus, en ce qui concerne les taux de réponse globale, des taux de participation d'experts, et de consensus sur les indicateurs, sont considérés plus que satisfaisants. Aussi, les experts ont confirmé la validité des enjeux et des interactions proposés.CONCLUSIONCet exercice de modélisation théorique, ainsi que l'enquête Delphi, ont permis l'identification d'une première série d'indicateurs des systèmes alimentaire durables, et d'obtenir un consensus tout en évitant le risque d'une évaluation individuelle et subjective, afin de supporter le processus décisionnel. L'opérationnalisation des théories de la vulnérabilité et de la résilience, grâce à une approche basée sur des indicateurs, a fourni une démarche spécifique pour l'analyse des problèmes de la durabilité du système alimentaire.

	Paolo PROSPERI ED 231 -Paolo PROSPERI ED 231 -
	1	2	3	4	5	6	7	8	9
	Nutritional quality (of food supply)
	Affordability of food
	Dietary energy balance
	Satisfaction of cultural food preferences
	[NEW] (Physical) Accessibility
	[NEW] Food safety
	[NEW] Food governance
	[NEW] Environmental externalities
	[NEW] Social equity

Mots clés: Systèmes alimentaires, Sécurité alimentaire, Durabilité, Résilience, Méditerranée, Indicateurs.

UMR 1110 MOISA Montpellier Supagro & Università di Catania -DiGeSA (Di3A) PhD Thesis in Agrofood Economics

Except for the Occupied Palestinian Territories.

The share of different commodities in total supply is used also as a proxy metric of dietary diversity, which is strictly linked to health and nutrition factors.

The concept of virtual water clearly depicts the global shifts of water embedded in products. Virtual water associates consumer goods to an amount of water needed to produce them. For instance the difference in water consumption was measured between a diet rich in meat (5400 liters virtual per day) or vegetarian (2600 liters) for American eaters[START_REF] Hoekstra | Virtual water trade: A quantification of virtual water flows between nations in relation to international crop trade[END_REF]. In particular virtual water indicates the volume of freshwater used to produce a given good, counted at the place where the product was de facto produced[START_REF] Hoekstra | Globalization of water: Sharing the planet's freshwater resources Appendix XX: Water footprints of nations[END_REF][START_REF] Van Oel | The external water footprint of the Netherlands: Geographically-explicit quantification and impact assessment[END_REF]. The concept of virtual water reveals how much water is needed to produce different goods and services.

This chapter is adapted from: Prosperi P. & Allen T., Modeling Sustainable Food Systems (Submitted to a peerreviewed scientific journal on December 2014).

In the same way as consumers or producers are considered price-takers, in perfect competition, although price is collectively defined when overall demand and supply meet.

Acknowledgments

The idea of doing a PhD was first suggested to me in 2009 by Martine Padilla, the initiator and main supporter of this PhD, during the Master and the internship at the ANNEX 3: Indicator list ‰ Score d'adéquation aux recommandations nutritionnelles indicator, collected by the Development Assistance Committee (DAC/OECD), can be used to follow biodiversity aid flows through the use of the 'Rio markers' for 'biodiversity'. For an activity to be labelled with this 'Rio marker' it must promote one of the three objectives of the CBD: the conservation of biodiversity, sustainable cumulative amount of health. The Concentration Index is then defined as twice the area between the concentration curve and the diagonals. Similarly, the "Nutritional Inequality" Concentration Index (Allen, 2010) measures the socioeconomic inequality of nutrition adequacy scores by taking into account, for selected measures of nutritional adequacy (MAR, MER, MAR/DE), every individual's level of and every individual's rank in the socioeconomic domain. The resulting concentration index cumulative amount of health. The Concentration Index is then defined as twice the area between the concentration curve and the diagonals. Similarly, the "Nutritional Inequality" Concentration Index (Allen, 2010) measures the socioeconomic inequality of nutrition adequacy scores by taking into account, for selected measures of nutritional adequacy (MAR, MER, MAR/DE), every individual's level of and every individual's rank in the socioeconomic domain. The resulting concentration index

The Nutrient density score (SAIN-Score d'adéquation aux recommandations nutritionnelles in French) is a nutrient density that evaluate the capacity of a food product -% of high school students watching TV ≥3 Percentage of high school students who watched television ≥3 hours per day.

Percentage of adults (years 15+) who can, with understanding, read and write a short, simple statement on their everyday life. Generally, 'literacy' also encompasses 'numeracy', the ability to make simple arithmetic calculations. This indicator is calculated by dividing the number of literates aged 15 years and over by the advertising. Classification into 3 categories: "compliance", "non-compliance" and "uncertain compliance". Number of eco-label products. Eco-label is a voluntary certification scheme that is awarded to products and services with reduced environmental impacts.

indicator, collected by the Development Assistance Committee (DAC/OECD), can be used to follow biodiversity aid flows through the use of the 'Rio markers' for 'biodiversity'. For an activity to be labelled with this 'Rio marker' it must promote one of the 3 objectives of the CBD: the conservation of biodiversity, sustainable use This is the third and last round of the "Metrics of Sustainable Diets & Food Systems" online survey! Thank you for connecting again.

We invite you now to confirm or amend your previous choices, considering the overall results from the panel, and further comment the framework and indicators.

You will find the general results of the second round in the questionnaire. Please refer to the "your name_INDI_R3.pdf" file (attached to the last email you received) for individual feedback. We encourage referring to this document to check your previous choices and to the companion document for the details of the indicators.

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Affordability of food ANSES French Agency for Food, Environmental and Occupational Health & on Biological Diversity CC Climate change CFCP Changes in food consumption patterns CGIAR Consultative Group on International Agricultural Research CIHEAM International Centre for Advanced Mediterranean Agronomic Studies CVD Cardiovascular disease DEB Dietary energy balance DEFRA Department for Environment, Food and Rural Affairs (United Kingdom) E Exposure EEA European Environment Agency EIU Economists Intelligence Unit ETC/SCP European Topic Centre on Sustainable Consumption and Production EU European Union FANTA Food and Nutrition Technical Assistance Project (USAID) FAO Food and Agriculture Organization of the United Nations FNS Food and nutrition security FPV Food price volatility FSSIM-Dev Farm System Simulator for Developing Countries GECAFS Global Environmental Change and Food Systems project GFN Global Footprint Network GFSI Global Food Security Index GHG Greenhouse gas GHGE Greenhouse gas emissions IAMM Mediterranean Agronomic Institute of Montpellier IFAD International Fund for Agricultural Development INFOODS International Network of Food Data Systems INRA French National Institute for Agricultural Research IPCC Intergovernmental Panel on Climate Change IUCN International Union for Conservation of Nature MA Millennium Ecosystem Assessment NQFS Nutritional quality of food supply OECD Organization for Economic Co-operation and Development Oqali Food quality monitoring service (INRA, France) PARME Partnerships and Research in the Mediterranean PCA Principal component analysis PDF Portable Document Format PI Potential impact PIPAME Interministerial center for forecasting and anticipation of economic transformation (France) R Resilience RP Recovery potential S Sensitivity SAFA Sustainability Assessment of Food and Agriculture systems (FAO) SCAR European Union Standing Committee on Agricultural Research SCFP Satisfaction of cultural food preferences SES Social-Ecological Systems UN United Nations UN-ECOSOC United Nations Economic and Social Council UNDP United Nations Development Programme UNDRO United Nations Disaster Relief Organization UNEP United Nations Environment Programme UNEP-MAP United Nations Environment Programme Mediterranean Action Plan UNESCO United Nations Educational, Scientific and Cultural Organization USAID United States Agency for International Development UNSDSN United States Sustainable Development Solutions Network V Vulnerability WB The World Bank WCED World Commission on Environment and Development WD Water depletion WFN Water Footprint Network WFP United Nations World Food Programme WFS World Food Summit WHO United Nations World Health PROSPERI ED 231 -UMR 1110 MOISA Montpellier SupAgro & Università di Catania -DiGeSA (Di3A)

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The goal of this expert consultation is to select indicators and explore the different approaches to assess the sustainability of diets and food systems.

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13. In order for sustainability to be a useful criterion for guiding changes, its characterization should be system-oriented, predictive and diagnostic.

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