Diane-Laure Arjaliès
email: diane-laure.arjalies@essec.fr

Jean-Pierre Ponssard
email: pierre.ponssard@polytechnique.edu

A Managerial Perspective on the Porter Hypothesis The Case of CO 2 Emissions

Keywords:

les investisseurs et les entreprises réalisent de plus en plus que le changement climatique et les besoins qui y sont associés vont impacter structurellement l'économie. Dans cette optique, ce papier cherche à comprendre ces impacts sur la stratégie des entreprises, à travers l'étude des systèmes de management. Une typologie est proposée, basée sur un modèle en deux étapes. A l'étape une, la firme aborde la question du CO 2 sous l'angle du risque et de la mise en conformité. A l'étape deux, la firme est impliquée dans une réévaluation plus globale de ses relations avec ses clients et fournisseurs. Cette construction est basée sur trois études de cas : Dupont (chimiste), Lafarge (matériaux de construction) et Unilever (produits de consommation). Des implications sont tirées de cette analyse pour les investisseurs.

Introduction

Over the past decade, the debate on climate change has dramatically shifted. The strong evidence presented by the scientific community through the Intergovernmental Panel on Climate Change (IPCC) process established by the United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO) has largely settled the discussion about whether an action should be taken to stabilize atmospheric greenhouse gases (GHGs) [START_REF] Parry | Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change[END_REF]. Climate change is now acknowledged as being a serious global threat which demands an urgent response. For example, the Stern Review on the economics of climate change estimates that without any global action, the overall costs and risks of climate change would be equivalent to losing at least 5% of global Gross Domestic Product (GDP) each year, which could rise to 20% if a wider range of risks and impacts are taken into consideration [START_REF] Stern | The Stern Review Report: the Economics of Climate Change[END_REF]. The question is: what should be the response to address the challenge of global warming while maintaining at the same time an economic growth (Mc Kinsey Global Institute, 2008). With this in mind, environmental concerns are becoming an increasing central topic for strategic choices and decision-making by investors around the world. 3 According to leading consultancy, investors would be more than 80% to consider climate change as a very or somewhat important factor when investing (Mercer Investment Consulting & Carbon Disclosure Project, 2009). The Carbon Disclosure Project (CDP) was launched in 2000 to collect high quality information on CO2 emissions. In 2009, it provided information concerning over 2,000 organizations in 66 countries, and grouped no less than 475 institutional investors -holding $55 trillion in assets under management -and 60 purchasing organizations. 4 However, despite assessing CO2 emissions as a key dimension to analyze when selecting companies for the portfolios, a significant number of investors acknowledge to keep working on how to integrate climate data into their existing systems, models and processes. 5 Almost five years after the European Union Greenhouse Gas Emission Trading System (EU ETS) debut of operation, Mercer concluded its study by stating that only 3 For example, the Fonds de Réserve pour les Retraites (FRR) -the major French public pension funddeclared: "Environmental concerns and, in particular, the global warming's impact on global economy and its different sectors put forward by the scientific community, raise a lot of questions a long-term investor cannot ignore when deciding its global investment strategy." [START_REF] Frr | Comment prendre en compte l'environnement dans la politique d'investissement du FRR ?[END_REF] 4 Carbon Disclosure Project : https://www.cdproject.net 5 For example, hardly any investor anticipated in 2006 the increase by 62% of Rhodia's stock due to a major reduction in total greenhouse gas emissions (GHGs) in South Korea [START_REF] Revenu | Le chimiste Rhodia amorce un solide rattrapage boursier[END_REF]. a very small handful of investors have succeeded in directly and systematically taking into account climate considerations into their actual stock selection.

The discrepancy between the major restructuring consequences of the climate change challenge and the relatively slow response of financial professionals may be explained by two very different factors. Firstly, for years, environmental pressure had been perceived by investors neither as a risk nor as an opportunity which could structurally impact companies' bottom line. As a direct result, investors have historically regarded explicitly and addressing environmental factors in their investment strategies as incompatible with their fiduciary responsibilities (Innovest, 2007). The context has now significantly changed. Secondly, at a more fundamental level, the lack of academic consensus on the macro-impacts of environmental regulations on the profitability of firms did not provide a sound basis to develop operational tools. Indeed, when analyzing the academic literature, two approaches emerge. On the one hand, a view, known as the "Porter hypothesis" [START_REF] Porter | The Competitive Advantage of Nations[END_REF][START_REF] Porter | Toward a new conception of the environmentcompetiveness relationship[END_REF] asserts that stricter environmental standards can spur innovations which enhance competitiveness and contribute to make companies more profitable. This virtuous mechanism is said to lead to the so-called "win-win" situation in which both a better environment and a higher financial performance are achieved. This view has benefited over the past decades from a growing interest among politicians and practitioners. 6On the other hand, according to a neo-classical economic perspective, tightening environmental regulations through norms or taxes, will reduce the choice set of the firm and cannot benefit a profit maximizing firm [START_REF] Fogler | A note on social responsibility and stock valuation[END_REF]. Indeed, [START_REF] Palmer | Tightening Environnemental Standards: The Benefit-Cost or the No-Cost Paradigm[END_REF] use the standard economic framework to demonstrate that more stringent environmental constraints cannot generate a higher profit, even if the firm innovates. They also provide counter arguments as regards the fact that more stringent environmental evidence in the US in the 80's relative to the EU or Japan would have caused the possible loss of competitiveness of US industry.

The academic attention has then shifted from macro to micro evidence. [START_REF] Wagner | The Porter Hypothesis Revisited: A Literature Review of Theoretical Models and Empirical Tests[END_REF] reviews more than 20 empirical studies which have tested the Porter hypothesis and shows that no relationship between environmental regulations and financial performance can be demonstrated. [START_REF] Ambec | Does it pay to be green? A systematic overview[END_REF] identify three possible ways in which environmental constraints may induce higher profit: cost reductions, increased revenues and lower cost of capital. They review the empirical cases in this respect, pointing out positive or contradictory evidence.

Altogether, it is not surprising that investors be still in search for adequate tools to assess the impacts of more stringent CO2 regulation on their portfolios. In this paper, we want to contribute to this question by providing a systematic framework to evaluate the response of firms to this new environment. We take the position that previous studies on the Porter hypothesis at the micro-level have neglected an important factor that could explain the ambiguity of the empirical results: the managerial dimension of strategy, i.e. the organizational conditions in which a firm elaborates and implements its strategy. We suggest that environmental regulations can systematically lead to a better financial performance only if the new strategic choices have led to a transformation of organizational processes and management systems. This view is in line with some previous work. For instance, Ambec and Barda (2002) associate the Porter hypothesis with agency problems. [START_REF] Gabel | The firm, its routines and the environment[END_REF] attribute the hypothesis on the prevalence of organizational routines. Our model also takes into consideration the fact that agents in the firm operate under bounded rationality and informational constraints.

To elaborate our construction, we build upon a comparative study of three companies belonging to different sectors, to wit: DuPont (chemicals), Lafarge (building materials) and Unilever (consumer goods). These firms operate at different levels of the added value chain:

DuPont provides components to manufacturers, Lafarge belongs to the manufacturing sector and Unilever delivers goods for the final consumers. This differentiated choice obeys a twofold will: 1) to provide a general model of change regardless of the firm's business and 2) to analyze the managerial dimension of the Porter hypothesis in firms which face different forms of environmental regulations and pressures regarding climate change. Indeed, we believe that organizational and business diversities are key advantages when developing managerial models.

The paper is structured as follows. Section 2 explains what we mean by a managerial perspective, building on Simons' synthetic work on organizations [START_REF] Simons | Levers of control: How Managers use Innovative Control Systems to Drive Strategic Renewal[END_REF]. It also reviews a preliminary positioning of firm's environmental and social strategy in those terms, based upon an empirical survey of large French firms [START_REF] Arjaliès | CSR: a new business model for multinational companies? A study of the management systems used by the French CAC 40 companies to integrate CSR into their strategy[END_REF]. This positioning will be used to construct our own typology. Section 3 introduces this typology. It is hypothesized that firms follow a two stage process: at the first stage, the strategy of the firm is associated with awareness/risk while at the second stage it is associated with vision/opportunities. The relevance of this model to structure the strategies actually followed by DuPont, Lafarge and Unilever is discussed in details. Section 4 revisits the Porter hypothesis. Section 5 comes back to the investors, and draws the implications of our results for the design of adequate tools to assess the impacts of climate change on portfolio analysis, giving due consideration to the factors that may trigger the passage of a firm from stage one to stage two. Section 6 concludes.

2 The managerial framework and some preliminaries findings on how firms manage CSR

The managerial framework

To adapt to its environment, a firm must keep innovating and evolving. According to bounded rationality perspective [START_REF] Cyert | A Behavioral Theory of the Firm[END_REF], firms should encourage organizational learning [START_REF] Argyris | Organizational Learning[END_REF] and local initiatives for generating emergent strategies [START_REF] Mintzberg | Mintzberg on Management: Inside Our Strange World of Organizations: Hungry Minds Inc[END_REF] while controlling that the chosen strategies are well implemented. [START_REF] Simons | Levers of control: How Managers use Innovative Control Systems to Drive Strategic Renewal[END_REF] -The other two systems refer to the planning and control procedures. In particular, they are concerned with the information systems needed to support these procedures.

o Diagnostic systems typically involve a wide range of indicators, which reflect the different facets of a company's performance, for internal or external use. They aim at ensuring that managers meet the firms' strategic goals. Control is made by exception, with actions taken whenever reported data widely differ from targets.

o Interactive systems involve a limited range of indicators to create a total determination of the management on a selected set of goals. Their purpose is to stimulate organizational learning by encouraging managers to innovate. The control takes the form of a very high degree of interaction along the hierarchical line. The interactive control systems will focus on areas varying from company to company according to a critical performance criteria.

It is the joint use of these four systems which permits firms to drive strategic renewal by favoring continuous innovation and ensuring that the implemented strategic actions are coherent and efficient. A summary of this process is provided in figure 1. In his research, Simons gives particular attention to the differences between diagnostic and interactive systems. He points out the connection between the major sources of strategic uncertainty (regulatory constraints, cost efficiency, launching of new products…) and the interactive systems to be put in place. He also emphasizes that the design of managerial compensation should be different in both systems. Compensation should typically be based on objective criteria for the diagnostic systems which are result oriented, and on subjective criteria for the interactive ones which are process oriented. Objective and subjective criteria constitute the extrinsic part in the motivational system of the firm. The beliefs systems of the firm have a direct role on the intrinsic motivation of the employees and as such they contribute to their alignment with the goals of the firm. 7 7 That intrinsic (i.e. symbolic) and extrinsic (i.e. financial) motivation need to be thought as complements has become an important issue [START_REF] Bénabou | Incentives and Prosocial Behavior[END_REF].

The relevance of this framework has been illustrated by a number of case studies made by Simons and others. 8 Simons' approach will be used as a starting point for our model. Two other dimensions need to be added to provide our managerial framework. The first dimension refers to the necessary cross-functional aspect of environmental strategies: interactive systems should be designed so as to promote horizontal interaction, for instance between functional and operational departments to evaluate the risks, and to design appropriate responses. This cross-functional dimension of management systems is not addressed by Simons in his typology while it is an important feature in the implementation of turnaround strategies. 9 The second dimension relates to the participation of external stakeholders such as NGOs and scientists in strategic deliberation. More than on any other corporate topics, environmental issues may involve an important number of firms' outsiders. As a result, Simons' framework should be used both at the internal and external levels, focusing explicitly on the relationships between firms and their stakeholders.

How firms manage CSR: some preliminary findings

In this section, we revisit a recent comparative analysis of the CAC 40 companies10 conducted by Arjaliès and Péan (2009). 11 The main finding of this analysis is puzzling: while companies have acknowledged the strategic importance of CSR for businesses, they still devote limited ressources and time to such concerns. The study demonstrates that companies

have not yet developed appropriate management systems to trigger strategic and practical change. According to the authors, this is the main reason explaining why no strategic renewal has yet been conducted by these companies to meet the CSR challenge. In line with our general management perspective, different elements can be put forward from this study:

CSR is now deemed to be essential for companies' long-term survival.

CSR has progressively become a major issue at the corporate level. Indeed, companies must meet an increasing number of demands regarding CSR both from their clients and stakeholders. As a result, CSR would become as of now a necessary pre-requisite for companies to be able to maintain their business and their so-called 'license to operate'.

However, the integration of CSR concerns remains limited in practice.

The recognition of CSR as a corporate issue has not been translated into operational goals. Firstly, CSR has not yet generated many demonstrative business cases. Secondly, CSR demands are rarely framed on the situations experienced by operational managers in practice.

Thirdly, companies face difficulties when implementing CSR strategies as a result of their lack of cross-functional approach. Finally, despite their assertion on CSR importance for business, most companies would still separate CSR issues from business related issues.

Diagnostic systems dominate for external reporting.

This focus of diagnostic systems on external reporting can be explained by the domination in practice of a risk approach of CSR. In other words, management systems would be first used to avoid behaviors which could endanger companies' license to operate and not to generate strategic opportunities. The study gives the evidence that the means dedicated by the companies to CSR are too limited to permit the generation of structural strategic change.

For example, the important feedback dimension of control systems is lacking in many companies. This prevents from a systematic process of improvement of existing practices.

Interactive systems exist but their influence is limited.

As for diagnostic systems: interactive systems suffer from a lack of feedback, which makes the capitalization on innovative ideas difficult. Moreover, managers' commitment to such systems is limited, as a result of their perception of CSR as being meaningless for business as usual. Thus, whereas companies assert that CSR is likely to play a key role in terms of innovation and strategic renewal, only few of them are able to design interactive systems to achieve the associated goals.

This study provides a broad picture in which it demonstrates that CSR is more and more integrated into the beliefs systems of firms, but mainly as a risk/compliance issue. The diagnostic systems are adapted to provide the data required by external bodies (regulatory and social rating agencies, NGOs…) through emerging standards such as GRI (Global Report Initiative). Boundary systems are almost not impacted and there is no CSR action program followed by innovative interactive systems. This shows that companies still separate CSR actions from business as usual. We will see in this paper that detailed case studies provide a less extreme picture (see also the other case studies included in this volume). Our goal is precisely to provide a systematic framework to organize isolated case studies.

The two stage model for implementing a CO2 strategy: from awareness/risk to vision/opportunities

In this section, we elaborate on the general framework introduced in section 2 to formulate the hypothesis on how firms implement their CO 2 strategy. The hypothesis is explained as a two-stage model. In simple words, stage one would correspond to the situation described in the preceding survey and applied to CO 2 : climate change appears as an awareness/risk issue mostly of concern at the corporate level. We shall hypothesize that some operational actions may still take place, as long as the corresponding programs are directly aligned with the compliance goals formulated at the corporate level. Stage two is not based on the survey but on our detailed case studies. We shall hypothesize that firms in stage two will consider climate change as an opportunity and characterize the four management systems that, in our view, would support such a strategy. An important theoretical question will then be addressed: are there conditions that could trigger the passage for firms from stage one to stage two? This question will be addressed in section 4, while revisiting the Porter hypothesis.

The main ideas underlying the model

We start by giving the main ideas of the model and then discuss them in full.

-Stage 1: Awareness/Risk CO 2 risk is identified but awareness is limited in the sense that only some managers in the firm, typically functional managers at the corporate level, are aware of this risk and can provide quantifiable measures in terms of loss of revenues and/or increase of costs. Neither the beliefs nor the boundary systems are affected by change. Some specific actions may be undertaken to counter change due to CO 2 regulation in the environment, such as delaying its impact on firm's activities through lobbying and/or mitigating emissions in production. Changes in the boundary systems make possible strategic formulation at the corporate level for the whole sector, along the chain value, with the goal to identify the strengths and weaknesses of the firm relative to its competitors, suppliers and customers.

The strategic orientation is explained through action plans. These action plans are explicitly introduced into the control systems. Dedicated diagnostic systems are integrated into the general planning and control systems of the firm. Dedicated interactive systems are designed to follow up the targets associated with the new vision.

Revisiting DuPont, Lafarge and Unilever strategies through this model

Our model is now applied to revisit the respective implementations of CO 2 strategy in DuPont, Lafarge and Unilever. Figure 2 provides a synthesis view of these firms in 2008. It gives their CO 2 emissions levels as of today and summarizes their current targets on these emissions. The three firms generate CO 2 mainly through their manufacturing activities, with some or many European Union (EU) plants eligible for the EU-ETS 12 , in our case for Unilever and Lafarge respectively. In the US, all firms have plants that would potentially be subject to a CO 2 regulation. However, the relative significance of these industrialized CO2 emissions is more important for Lafarge, with cement representing both its major product and its main source of emissions, than for the other two companies which are diversified. DuPont is an upstream company which produces industrial components for electronics, textiles, motor vehicles, construction materials, agriculture and plastics and so forth whereas Unilever is a downstream company which produces consumer goods through around 400 brands covering food, household and personal care products. The 'test' of our model for these differentiated companies will provide an indication of their potential value to handle many different situations. We are using the outputs of these case studies to give substance to our model. In this construction, it will be important to keep in mind that we refer to CO 2 in a broad sense so as taking into account the diversity in which the operations of these three companies affect the climate. DuPont's involvement started with the recognition of the CFC impact on the ozone hole. Unilever's involvement mainly comes through the sourcing of palm oil and its impact on Moreover, the Nations' commitment (i.e. countries in Annex B of the Protocol) to reduce emissions by 5.2% on the period 1990/2012 will not be reached. To say the least, the

DUPONT

Copenhagen meeting, in December 2009, did not lead to an international binding agreement.

Deforestation had remained largely ignored by the Kyoto protocol. Firstly, deforestation mainly occurs in developing countries (which are not in Annex B). Secondly, following the principle of common but differentiated responsibilities, these countries did not have to commit to any reduction of emissions. Furthermore, despite international debate on this issue, forest conservation projects are excluded from the Clean Development Mechanism. 14 This timing of events will have important consequences in the awareness process that occurred in the companies.

-Stage 1: Awareness/Risk Keeping this historical context in mind, we are now discussing similarities and differences in the strategies of DuPont for the CFC risk and Lafarge for CO 2 risk. In both cases, the emissions concern the manufacturing operations of these companies.

Awareness

The quantification of the risks for both firms is easy. In the early eighties, DuPont had 50% market share in CFC in the US and 25% worldwide with this business accounting for 2% of total sales . 15 In 2008, cement accounted for 57% of Lafarge total sales, the cost increase in cement at a price for CO 2 of 30€/t would induce an increase in cash cost of about 20€/t (based on an emission rate of .7 ton CO 2 per ton of cement). This puts the cement industry as the most affected sector in terms of cost increase (the unit cost being around 45€/t), making the EU cement industry vulnerable to pollution heavens (relocation in countries that would not regulate their CO 2 emissions). 16 Actions at the corporate level to mitigate regulation On both sides, awareness triggered some lobbying effort to delay regulation. DuPont launched a voluntary effort of industry through the Alliance for Responsible CFC as early as 1980. DuPont also publicly questioned the scientific connection between CFC and the ozone hole, but founded public research to get further evidence. Lafarge had discouraged early attempts to introduce a carbon tax in France in the nineties and prompted industry efforts during the renegotiation phases of the successive EU-ETS to have cement classified as a "sensitive" sector to reduce the impact of a unilateral CO 2 price in the EU on the competitiveness of the industry. 15 For a detailed account of DuPont CFC strategy, see [START_REF] Smith | Ethics of Du Pont's CFC Strategy 1975-1995[END_REF]. The data mentioned in this paper in relation to CFC mostly comes from this article. 16 Competitiveness issues for the cement industry are discussed in particular in [START_REF] Hourcade | Differentiation and dynamics of EU-ETS industrital impacts[END_REF]. See [START_REF] Ponssard | EU Emissions Trading and the Cement Sector: a Spatial Competitive Analysis[END_REF] for a quantification of these issues.

Corporate commitments

The risk for business also triggered positive actions. DuPont openly recognized that if a valid scientific connection was established between CFC and the ozone hole, it would immediately stop its CFC production. As a matter of fact, the scientific consensus was almost total prior the Montreal protocol. Consequently, in 1988, DuPont made public its decision to reduce its CFC production to zero by 1994. 17 In 2000, the CEO of Lafarge made a public commitment to reduce the Lafarge emissions of CO 2 by 20% over the period 1990 to 2010.

Such statements seemed to have come as surprises for operational managers in both companies. According to internal sources, these managers did not consider that it would be feasible.

No change in boundary systems but a slight adaptation of internal control systems

At the operational level, both companies integrated CFC and CO 2 risks respectively as being part of their business as usual. In DuPont, which is a 'science' company making its profit on technical innovations, the CFC risk induced R&D programs to elaborate substitutes to CFC, but the R&D budget remained in line with the average R&D spending in other areas.

Lafarge operational commitment for CO 2 was associated with its ongoing energy efficiency program which involved optimization of inputs (gas, coal, electricity, biomass,…), optimization of yields, as well as the incremental substitution of cementations materials (slag, flying ashes) for clinker, being the high energy intensive ingredient in cement. Thus, in both companies, no radical change was encouraged through specific new programs and/or design of specific incentives. The nature of these operations demonstrates that both companies' boundary systems had not changed.

Differentiated impacts on beliefs systems

There are some interesting differences between the two companies in terms of beliefs systems. For DuPont, its CFC strategy has been progressively reintegrated into its larger corporate environmental targets. DuPont environmental commitments in 1989 involved 70% reductions in air toxics and 90% reductions in air carcinogens, 35% less in hazardous waste. 17 DuPont had just developed a clean substitute for CFC at that time. This certainly helped to make that a decision that was considered as a complete reversal by other members of the Alliance for Responsible CFC. Still the commitment to eliminate CFC by 1994 remained ambitious due to the many applications and the sunk investments in these applications.

In 1994, DuPont further committed to a 40% reduction in GHG emissions (2000/1990). 18 In contrast, Lafarge operations in CO 2 were not connected to its long standing commitment on environmental issues (the license to operate for cement plants requires special attention to local stakeholders for quarries, logistics, emissions of gases and dust; this also concerns the other activities of Lafarge, thus its global involvement in environmental issues). Interestingly, Lafarge had its CO 2 goal certified by WWF in 2000, but did not use this partnership to change its beliefs systems. CO 2 remained a public relation issue at the corporate office to quantify the risk for the company and external lobbying efforts, and a reinforcement issue on energy efficiency programs for operations.

-Stage 2: Vision/Opportunities So far, in our analysis, climate change issues have not substantially changed the vision of the firm. At this point in the analysis, we will look at a 'turnaround', something that denotes that the 'frame' used to stimulate initiatives, evaluate decisions, promote managers, has changed.

DuPont, as a result of CFC has a clear historical advantage in this matter. It provides an illustrative example of such a change. Unilever will provide another illustration.

Changes in beliefs systems at DuPont

In 1999, DuPont coined a new term to describe its vision, "sustainable growth". This vision was associated with a major move of the company from fossil fuel technology to green technology. It acquired Pioneer in 1997, a major seed and biotechnology company and divested Conoco in 1998, a major oil company (acquired only a few years earlier). Its commitments were reformulated to highlight the change. The sustainability targets made in 1999 for 2010 involved a large spectrum of new goals: (1) to be flat on energy (base 1990) in spite of growth, (2) to source 10% of its energy use from renewable energy, (3) to remain below 65% in terms of its total GHG emissions compared to 1990, (4) to generate 25% revenues from products based on non-renewable resources. As a result of these major strategic choices, DuPont's beliefs systems shifted from just thinking of CO 2 as a liability/cost reduction issue to thinking about it as an opportunity issue as well.

Changes in beliefs systems at Unilever

As seen in figure 2, CO 2 direct emissions from Unilever are relatively low. However, the indirect impacts of Unilever activities on climate change are very significant. We already mentioned the case of deforestation. 19 Overall deforestation accounts for approximately 18 % of world total CO 2 emissions. Indonesia alone holds the global record for GHG emissions from deforestation, putting this country in the third place behind the USA and China in terms of total GHG emissions from human activity. That is the reason why, being the world leader buyer of palm oil, Unilever has been targeted by Greenpeace as fueling climate change.

Taking now other products of Unilever such as detergents and personal care products, the usages of these products are intensive in energy. As a matter of fact, while manufacturing activities in Unilever are not accountable for large CO 2 emissions, suppliers and customers of Unilever products are. To respond to this challenge, Unilever introduced its new vision about climate change around 2006, following an earlier awareness/risk phase similar to the one described above. The reduction of CO 2 emissions for Unilever is now part of its overall vision to minimize its environmental footprint (water, sustainable agriculture, energy, packaging…) all along the value added chain while delivering valuable consumer goods.

Changes in boundary systems

The reformulation of the CO 2 issue as a whole value-chain issue can be illustrated through the launching of long term global programs. DuPont has engaged in the developing of the next generation of bio-fuels: Cellulosic ethanol, a joint venture with Danisco, and Biobutanol, under development with BP. DuPont also creates value-adding materials from renewablesourced feed-stocks and bio-based ingredients for various industrial applications. DuPont is expecting that 60% of its business will stem from the use of biotechnology to reduce fossil fuels in the next decades. Such expectations need to be evaluated in the context of changes in the whole value chain with their indirect consequences for agricultural sustainability. In 2004, Unilever became a founding member of the Roundtable on Sustainable Palm Oil (RSPO). In May 2008, following a public challenge from Greenpeace, Unilever formalized its commitment to draw all its palm oil from certified sustainable sources by 2015. Through the RSPO, the company supports an initiative to put pressure on suppliers and users of palm oil to change their ways via certification bodies and NGOs. The future of this initiative remains uncertain, given the many usages of palm oil, often in small proportions to other ingredients, and by the many players at each level of the value added chain. 20 In some other activities, the global strategy seems easier to implement, such as in tea, an activity in which Unilever is also a world leader [START_REF] Poret | Integrating CSR into mainstream strategy: The case of Unilever with Lipton tea[END_REF]. In 2007, Unilever announced its commitment to achieve in 2015 a sourcing of all its tea sustainably from a Rainforest Alliance Certification. This certification involves measurements on ten sustainability indicators for producers: soil fertility, soil loss, nutrients, pest management, biodiversity, product value, energy, water, social capital and local economy. In all its divisions, Unilever managers implement a "Brand Imprint Tool" that prompts them to "think about where they source their ingredients and how they can get value from communicating this to consumers" (Paul Polman, Chief Executive Officer, Unilever website).

Diagnostic and interactive systems are systematically changed

To elect as part of a stage 2 strategy, we have to see how these visions have been

Putting the pieces together

The next two figures (3&4) summarize our two-stage model and its application to the DuPont case. Our analysis confirms the importance of transforming the four types of management systems in accordance with the CSR challenge. It also demonstrates that shifting from a stage one strategy based on risk and compliance to a stage two strategy whose goal is to generate new innovations and strategic opportunities requires: 1) a cross-functional approach, and 2) a coherent transformation of the four systems aligned with the new strategic targets. As claimed, it provides a more nuanced view than the broad picture described in section 2. As it will be seen shortly, it also provides a systematic framework to organize case studies.

STAGE

The Porter hypothesis revisited: what have we learnt?

In this section, we come back to the Porter hypothesis. Will an increased environmental pressure for the reduction of CO 2 emissions generate more profitability? Our contribution will be discussed at two micro levels: the firm level and the sector level. 21 We build on our exploratory research to formulate questions that look interesting to pursue.

There are probably as many case studies in which firms benefit from more stringent environmental regulation and societal pressure as ones in which they experience an increase in costs and a reduction in profits. Our own case studies confirm these ambiguous results. But we can go one step further since we propose a systematic framework to organize these cases studies. It suggests that the beneficial case studies would be more likely to be in stage two and the detrimental ones in stage one. A systematic test of this proposition would bring light on the capacity of the corresponding firms to either take full benefit of the change or be sucked in a compliance/risk strategy. Our main contribution on this question concerns the hypothesis that, to be in stage two, a firm must design its management systems in order to be in an alignment of the middle managers with the vision of the firm formulated at the corporate level. Another contribution of our analysis concerns the dynamic nature of stage two. The strategic turnaround that we associate with such a repositioning implies that the potential benefit is risky and long termed. It certainly cannot be considered as a "free lunch" as suggested by a literal interpretation of the Porter hypothesis.

A more general question may be stated at the sector level. For instance, are there structural factors that would imply that firms in the cement sector would be more likely to be in stage one while firms in the chemical or agro-food sectors would be in stage two? In other words, would Holcim and Cemex be positioned as Lafarge, while Bayer and Rhodia would be positioned as DuPont, and Danone and Nestlé as Unilever? It would indeed certainly be worthwhile to see if our model may be applied at the sector level: could steel, petroleum be considered as in stage one while chemicals, food, automobile… be considered as in stage two? Our research suggests some clues to investigate this point: whether the nature of the sector facilitates some diversification, whether it is concentrated on manufacturing or on the design and/or the assembly of components, or the significance of R&D and the speed with which new products are introduced into the portfolio… Finally, and probably the most challenging issue, is to address the question concerning the possible identification of the key factors that would trigger the passage from stage one to stage two at the sector level. For instance, one may consider that a sustained high price for petroleum would accelerate the passage of chemicals from stage one to stage two, assuming that it is not already there. The identification of some firms already in stage two, in a sector to be globally considered in stage one, would also be a key factor. For instance, it may be that some firms in the construction sector are already in stage two: such as construction builders which may have more flexibility to adjust their strategies than the manufacturers of cement and steel. Our research does indeed emphasize the changes that occur along the whole value chain and the development of partnerships to take advantage of these changes.

Implications for investors

In this section, we develop some implications that may be drawn from our work for investors that are concerned with the possible impact of climate change on the value of their portfolios.

It is interesting to note that the debate about CO 2 among investors is also progressively shifting away from cost and risk toward the question on how to capitalize on financial opportunities. Investors increasingly believe that climate change will present many business opportunities in the near future (Deutsche Bank Advisors, 2008;[START_REF] Securities | Climate change: To store or not to store?[END_REF].

According to a former leading consultancy, firms which will recognize the challenge of climate change early and elaborate on it to innovate will benefit from a competitive advantage and therefore prosper [START_REF] Brothers | The Business of Climate Change -Challenges and Opportunities[END_REF]. However, despite acknowledging the potential for strategic renewal regarding climate change, most investors keep assessing companies with an awareness/risk approach and not a vision/opportunities one. For instance, the assessment tool being used the most by investors to evaluate a firm's CO 2 emissions consists of calculating its carbon footprint, by estimating its number of Certified Emissions Reduction (CER). 22 The purpose of such calculation is to evaluate the financial gains/loss associated with the virtual valuation of these climate credits on the emission trading market (e.g. virtual valuation since investors do not directly benefit/pay for these CER). Although this assessment permits the identification of the firms which have mitigated their CO 2 emissions (i.e. stage 1), it does not enable the selection of the firms which have conducted strategic renewal according to climate change (i.e. stage 2). Yet, it is this second type of companies that investors should select for their portfolios to generate better financial performance in the long term.

For investors to shift from a stage one to a stage two approach when evaluating companies' CO 2 strategic approaches requires building new assessment tools. Our two stage model is an attempt to fill this gap. Namely, it should provide some guiding principles to the question "which firms are in a position to materialize what gains?" It suggests analyzing differently a company in stage one from one in stage two. In line with recent approaches developed by brokers (Oddo [START_REF] Securities | Climate change: To store or not to store?[END_REF] and social rating agencies (Innovest, 2007) to assess firms based on their business opportunities regarding climate change, our analysis insists on the importance of studying the potential for strategic and organizational change generated by CO 2 emissions at the sector and firm levels. Firstly, we suggest maintaining the so-called 'best-in-class' approach, which consists of selecting the best firms regarding CO 2 emissions in each sector. Two reasons motivate this choice: on the one hand, when building a portfolio, a firm must be assessed in comparison to its peers; on the other hand, it cannot be ignored that most of investors will not exclude sectors such as oil or building materials from their portfolios even if they are considered as a laggards in terms of CO 2 strategies. Secondly, we suggest identifying different scenarios according to the stage of the sector regarding CO 2 strategies.

These two different scenarios can be outlined according to the following approach:

-Scenario 1 -the whole sector is at stage one: in a few sectors, all firms appear to be more or less at stage one regarding CO 2 emissions, possibly in real estate, oil or building materials. In such cases, the traditional approach based on risk/awareness when assessing firms would be the rule. For instance, an investor could start by identifying the level of CO 2 emissions associated with the firm's operations and ask for actions that mitigate these emissions. It could proceed to identify the CO 2 content associated with the products, anticipating that a carbon tax of this content will affect the market value of these products.

-Scenario 2 -at least one firm in the sector is at stage two: this means that climate change has generated business opportunities for the sector, possibly in chemicals, water or food products sectors. When faced with this situation, an investor must favor the most promising firms regarding CO 2 strategies. These firms can be identified using the different characteristics developed in the second stage of our model, such as the reformulation of the firm's vision, corporate culture, the integration of dedicated diagnostic, interactive systems in the general planning and control systems of the firm.

A more challenging grid would ask why and when a firm would move from stage one to stage two. Our analysis suggests that the key factors to consider would be the following ones:

-The 'new vision' that incorporates climate change as a major ingredient of the company culture should be based upon in depth internal studies identifying the risks for the company and its capacity to successfully address these risks in a stage one strategy.

-The involvement of the CEO in the formulation and the communication of the new vision is a key factor, which is usual in organization theory. To discern such an involvement from green washing, it seems important to link the CEO vision to the formulation of explicit new CSR targets.

-The quantification of these new targets should be integrated in the management control systems; note that it is possible to evaluate from outside if this is the case through an analysis of the KPIs introduced at the business unit levels, along with changes in the compensation package, as well as in changes in the general strategic review process.

-The identification of a stage two strategy remains the change in the carbon intensity of the portfolio of activities of the firm, as well as their positioning into the whole value chain; the capacity of the firm to articulate its current strategy in this respect provides a direct indication that its vision has changed its boundary systems and is delivering results.

-An interesting factor for assessing the change from stage one to stage two may be that the firm now engages into positive partnerships and interactions with NGOs and scientists to formulate and implement its strategy.

This move from stage one to stage two is easier to identify in the second scenario (i.e. at least one firm in the sector is at stage two) than in the first scenario (i.e. all firms are at stage one). Indeed, in the second scenario, other firms can be assessed in comparison to the sector leader. In case of the first scenario, the reasons which explain why no firm has been in stage two must be searched: Do the technical problems that prevent from innovations require major breakthroughs? Are clients reluctant to change? Have the leaders an interest in the status quo?

Are the competitive forces not so important? And so forth. Once the reasons identified, investors may choose 1) to keep using a stage one approach when selecting the firms in the sector; 2) to encourage the leaders of the sector to shift from stage one to stage two; 3) to favor firms at stage two belonging to other sectors but which can be good substitutes (for example, investing in firms belonging to the oil services sector instead of the more classical integrated oil & gas sector). While our research has identified the existence of different stages to position a sector, further research is clearly needed to explain what prevents some sectors from shifting from stage one to stage two.

Conclusion

The objective of this paper was to revisit the Porter hypothesis from a managerial perspective. We have proposed a framework to position a climate change strategy of a firm consisting of a simple two stage model: awareness/risk, in which compliance and incremental improvements are the rule, and vision/opportunity, which may induce a more global reassessment of the portfolio of the firm including its relationship with suppliers and clients.

Our construction is based upon three case studies: DuPont (chemicals), Lafarge (building materials) and Unilever (consumer goods).

The results have been used to revisit the possible relationship between an increase in environmental constraints and the profitability of the firm, contingently at the stage the firm is considered to be in. Moreover, a number of key factors that may trigger the shift from stage one to stage two have been identified: integration of the climate change policy into the beliefs systems of the firm, involvement of the CEO in the formulation of the environmental targets for the whole company, integration of these targets into the planning and control systems.

Our work suffers from a number of limitations: our empirical base should clearly be extended. This may lead to a refinement of the model. At some point, this should generate a number of hypotheses that would be amenable to systematic testing. On the more practical side, the implications we have developed for investors should be made more operational. In spite of its limitations, firms and investors may also be interested in using our model to position their own strategy. The clear architecture of the model would facilitate this positioning and, hopefully, provide a useful starting block for further analysis.

  has elaborated a comprehensive framework to analyze strategic and organizational change in this framework. It relies on four performance systems. -The first two systems are key cognitive tools to 'frame' what can and cannot be done both in terms of behaviors and actions: o Beliefs systems set the core values of the company to create a sense of commitment and belonging on part of the employees. o Boundary systems set the framing for strategic elaboration and analysis. They orientate managers' actions by showing what is permitted.

Figure 1 :

 1 Figure 1: a dynamic relationship (source Simons (1995))

  Firm's control systems remain in place. Eventually, diagnostic systems are by increments updated to measure and mitigate the actual emissions. No specific interactive system is designed to elaborate and implement radical change.-Stage 2: Vision/OpportunitiesThe core values of the firm address the challenge created by CO 2 emissions in a positive way through a reformulation of the firm's vision and corporate culture. This induces a reformulation of the beliefs and boundary systems to drive strategic and organizational change.

Figure 2 :

 2 Figure 2: DuPont, Lafarge and Unilever at a glance

  deforestation. There have been different policies to tackle these different impacts and the firms' responses varied accordingly. Moreover, the public questioning on the detrimental effects of CFC emissions on CO 2 emissions from manufacturing and on CO 2 emissions from deforestation have not appeared at the same time and triggered different responses. The first scientific paper hypothesizing a connection between CFC and the ozone hole is from 1974. In 1987, the Montreal protocol to reduce and eliminate CFC was signed by 24 Nations and the EU. In 2007, 191 Nations revisited the Montreal protocol and expressed their satisfaction that all CFC production would end in 2010. Awareness of the GHGs on global climate change has been much slower than awareness of the impact of CFC on the ozone hole. The IPCC (Intergovernmental Panel on Climate Change) was founded in 1989. The scientific hypothesis that connects CO 2 and global climate change has been clearly formulated but an agreement on this hypothesis has not yet reached the same level of consensus as for CFC and the ozone hole. The Kyoto protocol was open for ratifications in 1998, but it sets binding targets for only 36 industrial countries so far.

  integrated into firms' management and management systems. The fact that the organizational chart and the control systems have changed are illustrative of such integration. For example, at DuPont, we now have a VP Chief Sustainability Officer, a Sustainable Growth Review for each business, a Corporate Environmental Plan, a more systematic link to compensation, decentralized competence centers for sustainable growth, local champions, awards… At Unilever, there are a Board-level Corporate Responsibility and Reputation Committee and a Corporate Responsibility, Issues, Sustainability and Partnerships (CRISP) leadership team, which review the BU strategic plans along the key performance indicators (KPIs) associated with the global sustainability targets. This illustrates the importance of both quantitative (KPIs) and subjective indicators (such as symbolic prizes associated to local champions and awards) in the incentive systems when conducting strategic renewal.

Figure 4 :

 4 Figure 4 : application to DuPont

Since Gore (1993), politicians have viewed the green economy as a chance for growth and competitiveness for the industry. See also[START_REF] Wagner | The Porter Hypothesis Revisited: A Literature Review of Theoretical Models and Empirical Tests[END_REF] on that subject.

See for instance[START_REF] Simons | How New Top Managers Use Control Systems as Levers of Strategic Renewal[END_REF],[START_REF] Bisbe | The Effects of the Interactive Use of Management Control Systems on Product Innovation[END_REF] and[START_REF] Marginson | Management Control Systems and their Effects on Strategy Formation at Middle-Management Levels: Evidence from a U.K. Organization[END_REF].

In his analysis of change atNissan, Goshn (2002) insists on setting ambitious targets for the company and on the key role of transversal working groups to by-pass the inherited compartmentalized organizational structure of the company. See also[START_REF] Ponssard | Planning in firms as an interactive process[END_REF].

The CAC 40 companies are the 40 biggest French listed companies.

This study is based on questionnaires and documentary evidence.

EU-ETS refer to the European Union Greenhouse Gas Emission Trading System, which is a major pillar of EU climate policy.

We interviewed executives from these three companies but also from other companies in the same sectors. We also interviewed financial analysts. We are indebted to these executives for their responses to our inquiry. The authors remain the sole responsible for the views and analysis presented in this paper.

This created strong incentives for firms operating in industrialized countries to involve themselves into emission reduction in developing countries.

[START_REF] Wagner | The Porter Hypothesis Revisited: A Literature Review of Theoretical Models and Empirical Tests[END_REF], it had reduced its emissions by 72%. Then it reset its base line in 2004, see current target figure 2.

On the link between Unilever and deforestation see the Greenpeace report(2008).

On December 11, 2009 Unilever announced that it suspended its supplies from Sinar Mas, until it provides substantial, evidence that its operations did not involved deforestation in Indonesia. Greenpeace considered this as a consequence of its pressure on Unilever.

We leave aside the macro level.

Certified Emission Reductions (CERs) are climate credits (or carbon credits) issued by the Clean Development Mechanism (CDM) Executive Board for emission reductions achieved by CDM projects and verified by a Department of Energy under the rules of the Kyoto Protocol.

Acknowledgments

The authors wish to thank Jean-Philippe Desmartin, Olivier Godard, Pierre Tegner and Bernard Sinclair Desgagné, for their precious comments on earlier versions of this article.


ACS AT EXOMARS TGO

O. Korablev 1 , A. Fedorova 1 , N. Ignatiev 1 , A. Trokhimovskiy 1 , Franck Montmessin 2 , and the ACS Team 1 Space Research Institute (IKI), 84/32 Profsoyuznaya, 117997 Moscow, Russia, 2 LATMOS/IPSL, 11 bd d'Alembert, 78280 Guyancourt, France

The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists of three separate infrared spectrometers. This ensemble of spectrometers has been designed and developed in response to the Trace Gas Orbiter mission objectives that specifically address the requirement of high sensitivity instruments to enable the unambiguous detection of trace gases of potential geophysical or biological interest. For this reason, ACS embarks a set of instruments achieving simultaneously very high accuracy (ppt level), very high resolving power (>10,000) and large spectral coverage (0.7 to 17 µm -the visible to thermal infrared range). The near-infrared (NIR) channel is a versatile spectrometer covering the 0.7-1.6 µm spectral range with a resolving power of ~20,000 [START_REF] Korablev | The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter[END_REF].

ACS-NIR employs the combination of an echelle grating with an AOTF (Acousto-Optical Tunable Filter) as diffraction order selector. This channel will be mainly operated in solar occultation and nadir, and can also perform limb observations. The scientific goals of NIR are the measurements of water vapor, aerosols, and dayside or night side airglows. The mid-infrared (MIR) channel is a crossdispersion echelle instrument dedicated to solar occultation measurements in the 2.2-4.4 µm range. ACS-NIR follows the lineage of the SPICAM-IR instrument operating in orbit around Mars since 2004 [START_REF] Korablev | SPICAM IR acousto-optic spectrometer experiment on Mars Express[END_REF]. The SPICAM-IR instrument family concept relies on a simple pencil-beam AOTF spectrometer covering the spectral range of 1 to 1.7 µm with a resolving power of ~2,000. This small instrument has continuously delivered high-quality data for the last 14 years to help us characterize the Martian climatic processes and aeronomy phenomena [START_REF] Montmessin | SPICAM on Mars Express: A 10 year in-depth survey of the Martian atmosphere[END_REF]. ACS-NIR with its ten-fold better spectral resolution will significantly enhance the fidelity of atmospheric measurements.

ACS-MIR achieves a resolving power of >50,000 in range of 2.2-4.0 µm and SNR of >5000 per pixel per 1s-acquisition. This new instrument based on echelle cross-dispersion concept and has been designed to accomplish the most sensitive measurements ever of the trace gases present in the Martian atmosphere.

The thermal-infrared channel (TIRVIM) is a 2-inch double pendulum Fourier-transform spectrometer encompassing the spectral range of 1.7-17 µm with apodized resolution varying from 0.2 to 1.3 cm -1 . TIRVIM is primarily dedicated to profiling temperature from the surface up to ~60 km and to monitor aerosol abundance in nadir. One may note its resemblance to 2.5-inch PFS/Mars Express [START_REF] Formisano | The Planetary Fourier Spectrometer (PFS) onboard the European Mars Express mission[END_REF], but the mass allocation for TIRVIM on TGO was far smaller than that for PFS. One-channel TIRVIM is expected to provide temperature profiling with higher accuracy along with better estimated of dust/clouds opacity. TIRVIM also has solar occultation capability for the retrieval of gases otherwise not detected by the two other channels, i.e. O 3 and H 2 O 2 , two gases of fundamental importance for photochemistry.

The science goals of the ACS experiment, the the expected performances of the instrument's three channels will be described and copared with the Mars Express PFS and SPICAM.

Scientific Workshop: "From Mars Express to ExoMars"

Acknowledgements: ExoMars is a space mission of ESA and Roscosmos. OK, AF, and AT acknowledge grant of Ministry for Education and Science of Russian Federation #14.W03.31.0017.

Workshop organized by ESA-ESAC & IAA-CSIC, with the support of the ESAC Faculty and the EU H2020 project UPWARDS


Helmut Lammer

Martin Leitzinger

Petra Odert

Christoph Burger

Darya Kubyshkina

Manuel Scherf

Thomas Maindl

Colin Johnstone

Nicola Tosi

Athanasia Nikolaou

Early evolution of Venus and Earth constrained by the reproduction of measured Ar, Ne isotope and K/U elemental ratios

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Early evolution of Venus and Earth constrained by the reproduction of measured Ar, Ne isotope and K/U elemental ratios Helmut Lammer, (1), Martin Leitzinger (2,1), Petra Odert (1), Christoph Burger (3), Darya Kubyshkina (1), Manuel Scherf (1), Thomas Maindl (3), Colin Johnstone (3), Nicola Tosi (4,5), Athanasia Nikolaou (4,5), Emmanuel Marcq (6), Luca Fossati (1), Nikolai V. Erkaev (7, 8), Manuel Güdel (3), Lena Noak (9), Kristina G. Kislyakova (3,1), Florian Ragossnig (3), Elke Pilat-Lohinger (3)

(1) Space Research Institute, Austrian Academy of Sciences, Graz, Austria, (2) Institute of Physics/IGAM, University of Graz, Austria, (3) Department of Astrophysics, University of Vienna, Austria, (4) Institute of Planetary Research, Department of Planetary Physics, DLR, Berlin Germany, (5) Department of Astronomy and Astrophysics, Berlin Institute of Technology, Germany, (6) LATMOS, Université de Versailles Saint-Quentin-en-Yvelines, Guyancourt, France, (7) Institute of Computational Modelling, FRC Krasnoyarsk Science Center SB RAS, Krasnoyarsk, Russian Federation, (8) Siberian Federal University, Krasnoyarsk, Russian Federation, (9) Department of Earth Sciences, Freie Universität Berlin, Germany

Abstract

We show that the measured present day atmospheric Ar, Ne isotope ratios and elemental K/U ratios measured for Venus and Earth can be reproduced by a combination of EUV-driven hydrodynamic hydrogen escape and impacts happening during accretion. We find that both protoplanets formed within the solar nebula and accreted large enough masses able to capture thin hydrogen envelopes, which were then lost within a few 10s of million years after disk dispersal. We further show that early Venus was surrounded by a denser primordial hydrogen-dominated atmosphere compared to a less massive proto-Earth that accreted its final mass by pre-fractionated dry impactors and about two percent carbonaceous chondrites after the thin primordial hydrogen envelope was lost. Our results agree with hafnium-wolfram isotope chronometric evidence that favors a fast accretion scenario of the Earth with a late Moon-forming impact. We conclude with a discussion on the implications of these findings in relation to planetary evolution of terrestrial exoplanets and their potential habitability.

Acknowledgements

We acknowledge support by theAustrian Fonds zur Förderung der Wissenschaftlichen Forschung, Nationales Forschungs Netzwerk (FWF NFN) project S116-N16 and the subprojects S11603-N16, S11604-N16, S11606-N16, and S11607-N16. H.L, M.L. and P.O. acknowledge support of the FWF project P27256-N27. D.K. and L.F. acknowledge the Austrian Forschungsförderungsgesellschaft FFG project "TAPAS4CHEOPS" P853993. The authors thank ISSI for the support of the ISSI team "The early evolution of the atmospheres of Earth, Venus, and Mars". N.T. and A.N. acknowledge support from the Helmholtz Association (project VH-NG-1017). M. Güdel and L. Noack acknowledge the collaboration within the COST Action TD 1308. The authors also thank the International Space Science Institute (ISSI) in Bern, the ISSI-Beijing team "Astrobiology" and the ISSI team"The Early Evolution of the Atmospheres of Earth, Venus, and Mars".


Frédéric Pourraz

Alain Duclos

François Louchet

AN INNOVATIVE PROTOCOL FOR CONDUCTING AND EXPLOITING SNOW TESTS: THE OUTCOME OF A RELIABLE FIELD EXPERIMENT AND THE DEVELOPMENT OF DIGITAL TOOLS ON SMARTPHONE

Keywords: Avalanche forecasting, snow tests, measurement protocol, propagation propensity, real-time sharing

The avalanche risk estimation, performed by a forecaster as well as a practitioner, is based on a limited number of parameters which are now subject to a consensus. Their measurement, processing, and dissemination are fundamental, as it is the preliminary step towards the complex forecasting task. The experiences and skills of experts from various cultures have been brought together to combine and refine the commonly used snow tests (CT, ECT, and PST) and thus formalize a complete measurement protocol. This protocol has been framed thanks to a Smartphone application that guides the user in order to guarantee measurements' homogeneity. It also facilitates result recording, whatever the weather conditions might be, but also their real-time sharing. With 543 tests carried out over three winter seasons, the protocol we propose, as well as the tools supporting it, are now robust. Their validity is assessed by conducting a certain number of them in areas where avalanches have just been triggered, or in their immediate vicinity. This dataset thus highlights multiple questions that contribute to refining our understanding of the slab-triggering mechanism. All these measurements are used as an input for the CRISTAL approach and are disseminated online thanks to SYNTHESIS, an innovative tool that provides an overview of all the useful information for decision support.

INTRODUCTION

The aim of this approach is not to create a new protocol for snow measurements, but rather to better address the needs of avalanche risk assessment, for both practitioners and forecasters. Although the value of snow tests is indisputable, they still come up against obvious difficulties of interpretation, which we have tried to reduce. They are used as a complement to other major information, such as observed avalanche activity and snow-meteorological measurements [START_REF] Van Herwijnen | Measurements of snow slab displacement in extended column tests and comparison with propagation saw tests[END_REF]. The danger level index from the bulletin may possibly be considered as an output rather than an input data, within this process.

The inherent uncertainty of spatial variability is reduced by choosing the locations for snow testing according to a well-defined process. The intention is not to repeat tests throughout the sea-*Corresponding author address:

Frédéric Pourraz LISTIC -University Savoie Mont Blanc 5 chemin de bellevue 74944 Annecy-le-Vieux FRANCE tel: +33 450 666 002, email: frederic.pourraz@univ-smb.fr son at predetermined sites, but rather choosing the test site expertly. It must correspond to the place where the stratigraphy seems, a priori, the most unstable, at both the sector level (exposure, altitude, etc.) and the slope level (topography, etc.). It requires travel in the mountains, multiple exploratory soundings with a ski pole (looking for stratigraphy of varying hardness) and then soundings with a probe before digging (is the total snow depth appropriate?).

The inherent uncertainty of snow tests significance is also reduced by prioritizing a PST test [Gauthier andJamieson, 2006, Sigrist andSchweizer, 2007]. Our goal is to evaluate crack propagation in a buried weak layer, which is the key phase of slab avalanche release processes [START_REF] Louchet | Insight into Slab-Avalanche Triggering: A Combination of Four Phenomena in Series[END_REF]], avoiding as far as possible bias due to failure initiation phase. This PST is carried out with an increased length, and performed after preliminary tests have been carried out to detect the weak layer to be characterized.

The objectives of this new testing process are manifold, including:

1. Detect the presence of one or more weak layers within the snowpack.

2.

Assess snowpack heterogeneity.

3.

Characterize the propensity of a local crack to propagate in the identified weak layer.

4.

Characterize the different layers of the snowpack throughout its entire thickness.

All these steps will be formalized in Section 2. We will discuss the first statistics from the first three winters of data collection in Section 3. We will also outline how these data are disseminated and used on a daily basis in Section 4. We will end with a discussion of the interests and limitations of the approach in Section 5, and conclude in Section 6.

MEASUREMENT PROTOCOL

Snow test location and trench template

The significance of any snow test depends on location choice. Our stated aim is to identify and characterize the most unstable spots in the explored area, which requires systematically probing the snowpack with a ski pole to detect any potential heterogeneity (layers of different hardness). As the aim is also to characterize the snowpack over its entire depth, we use the avalanche probe to find an area not exceeding, or slightly exceeding, a depth of 150 cm. This is an important prerequisite, given the almost systematic variability of snowpack thickness. For instance, a weak layer detected at a depth of 120 cm during a test might be buried only 30 cm deep a few meters away. It is therefore important to systematize trench clearing down to the ground, and therefore to limit its depth, so that the test can be carried out without wasting too much time and energy.

Although [START_REF] Gauthier | Evaluation of a prototype field test for fracture and failure propagation propensity in weak snowpack layers[END_REF] and [START_REF] Heierli | Anticrack model for skier triggering of slab avalanches[END_REF] have considered that the slope inclination has little impact on snow tests results, we find it important to account for its influence on test representativeness. This is why our tests are primarily conducted on slopes with a steepness close to 30°(always prioritizing the safety of observers), in order to avoid any unexpected influence of slanting. At least two reasons guided this choice: (i) the influence of slope angle on stratigraphy (at the start of the winter season, for instance, the grazing sun light maintains cold temperatures at the surface of shallow slopes, unlike steeper sun-exposed slopes), and (ii) the influence of steepness on the stress shear component.

To make our protocol as reproducible as possible, we formalized the trench excavation process (see Figure 1). The trench is systematically dug perpendicular to the slope line, using a new 240 cm-long template. Once again, we use our avalanche probe and ski poles to outline the perimeter of the digging area. Beforehand, we systematically check that the depth of the snowpack can be exploited over the entire length of the trench, by conducting a minimum of four probings spread over the 240 cm length. The aim is to ensure that no rocks or sudden terrain shifts are encountered during trench excavation. This notable modification compared to conventionally conducted tests allows us to optimize our template to combine several test types, as we shall see now.

Snow test significance and combination

One of the distinctive aspects of our approach is the combination of different tests and the consideration of their individual significance. Figure 1 illustrates the distribution of these tests along the trench.

Snow tests combination is formalized as follows.

A first CT of 30 cm by 30 cm, as proposed by [Jamieson, 1999], is carried out on the left side of the trench (CT1), followed by another one on the right side (CT2). Each of these CTs serves our first two objectives, i.e. (i) detecting the presence of one or more weak layers, revealed by a local crack resulting from dynamic overpressures, and (ii) assessing the heterogeneity of the snowpack by comparing the results of both tests, conducted 180 cm apart. As mentioned in Section 3, this heterogeneity may be significant, even for such a close spacing. Due to this reason, we have chosen not to follow the conventional CT protocol (10 wrist taps, 10 elbow taps and 10 shoulder taps [Jamieson, 1999]), opting instead for shoulder taps only. Given the intrinsic variability between CT1 and CT2, we believe that measurements as precise as wrist or elbow taps cannot be considered accurate. Lastly, as also mentioned in section 3, local collapsing does not necessarily ensure effective propagation within the weak layer. However, this propagation is a fundamental premise for slab avalanche release. Hence, this initial test stage involving two CTs is no more than an intermediate and indicative stage before carrying out a PST, which remains a pivotal component in assessing avalanche danger.

In the very small minority of cases where several weak layers are highlighted by the two preliminary CTs, we supplement the protocol with an ECT [START_REF] Simenhois | The extended column test: a field test for fracture initiation and propagation[END_REF].

In all other cases, we prioritize conducting a PST to address our third objective, i.e. to characterize the propensity of a local crack to propagate within the identified weak layer. Whatever the number of identified weak layers, we also conduct a PST when the top layers of the snowpack have quite a reduced hardness as the shovel edge tends to cut those layers and sink through [START_REF] Simenhois | The extended column test: a field test for fracture initiation and propagation[END_REF]].

[ [START_REF] Van Herwijnen | Measurements of snow slab displacement in extended column tests and comparison with propagation saw tests[END_REF] have shown that, irrespective of the failure initiation test (PST or ECT), the weak layer collapses to a similar extent, and the same holds true for the propagation speed of the crack. According to [START_REF] Ross | The propagation saw test: slope scale validation and alternative test methods[END_REF], PSTs also provide an comparable accuracy to other snow tests, and, unlike ECTs, PSTs can also test deeply buried weak layers [START_REF] Ross | Comparing fracture propagation tests and relating test results to snowpack characteristics[END_REF]. Moreover, the PST makes it possible to circumvent the influence of all the intermediate hard layers of varying thicknesses above the weak layer, allowing the least ambiguous and most comparable measurements.

Traditionally, a PST is conducted on a parallelepidedic snow block "with a length of 1 m or equal to the slab thickness (measured vertically), whichever is greater" [START_REF] Gauthier | Evaluation of a prototype field test for fracture and failure propagation propensity in weak snowpack layers[END_REF].

However, we have chosen to carry out the PST on the remaining 180 cm between both CTs. This corresponds to the upper limit of the protocol proposed by [START_REF] Sigrist | Critical energy release rates of weak snowpack layers determined in field experiments[END_REF] and is also in agreement with [START_REF] Bair | The influence of edge effects on crack propagation in snow stability tests[END_REF]. We justify this choice by the fact that, in the case of incomplete propagation, most propagations stop close to or beyond one meter, as shown in Section 3. Based on our dataset, a shorter column would not have adequately characterized the arrest condition of the crack propagation within the weak layer, a condition which is nevertheless another important parameter along with the critical cut length [START_REF] Gauthier | The Propagation Saw Test (PST): A Review of its Development, Applications, and Recent Research[END_REF].

After these tests have been carried out, a temperature and stratigraphic profile (using the usual procedure) enables us to meet the fourth objective, i.e. characterizing the various layers of the snowpack throughout its entire thickness. Therefore, this protocol leverages the strengths of each of the traditionally employed tests while making an effort to minimize the remaining limitations as much as possible. Formalizing the various stages of the protocol we have just described is a necessary but not sufficient step to ensure the reproductibility, recording, dissemination and interpretation of our snow tests. Therefore, we have developed a dedicated smartphone application for this purpose (see Figure 2). Firstly, in terms of reproducibility, our application guides the user throughout the different process stages. Recognizing that this process is more complex than traditional tests, we believe that this assistance is essential to maintain protocol uniformity, thus rendering the data usable and comparable.

Snow test guiding and recording App

Secondly, in terms of data recording, our application significantly simplifies data input with a userfriendly and intuitive interface. The application is fully functional offline, in all weather conditions, and it also enables automatic GPS coordinates collection for each test as well as a timestamp. Once all the information has been entered, and as soon as a network access is available, the test data is uploaded to the data-avalanche association's server, where it is stored and subsequently shared freely with the entire practitioner community (see Section 4).

STATISTICAL INTERPRETATIONS

After over 10 years of informal experimentation, test recording through the application started in 2020/2021 early winter. Three winter seasons later, 543 tests, all compliant with the previously outlined protocol, have been collected, constituting our database (see Figure 3). Among them, 50 tests identified multiple weak layers during the CTs, leading to the execution of an ECT. This subset will not be discussed in this article, as our focus will be on the 493 tests that revealed either a single weak layer or none at all.

In the subsequent sections of this article, the results of conducted CTs and PSTs will be categorized into four incremental classes, to simplify the interpretation of measurements. While acknowledging that this classification introduces a degree of imprecision, it's important to bear in mind that these tests are merely an imperfect simulation of the real phenomenon. Consequently, employing a classification with a finer granularity would be overly presumptuous.

CTs measurements

Within the considered subset, 39 CTs were conducted in areas of recent avalanche release or in their immediate vicinity, either on the same day or the day following the observed avalanche. Initially, it's from this subset of tests that we will extract the initial statistics to demonstrate the validity of our protocol. The four classes characterizing the results of the conducted CTs aim to classify the local crack following the failure initiation (shoulder tap(s) -see Table 1).

Failure initiation

Strong (CT)

Spontaneous (5 mm thick) was present, that probably evolved between the avalanche event and the test itself, conducted the following day. In the second one a persistent weak layer was deeply buried at a depth of 179 cm, and propagated completely during the PST within the initial centimeters of cutting. Finally, only one test was classified as Slight (CT) , corresponding to 2.56% of cases.

Here again, we note the presence of a very thin temporary weak layer (2 mm thick) coupled with a test conducted the day after the avalanche was triggered. Additionally, we observe that no test was classified as Negative (CT) . These statistics thus reaffirm the value of conducting a CT to detect the presence of a weak layer within the snowpack, as it corresponds with observations made during tests on proven avalanche releases.

In a conventional statistical study, these data would ideally be compared to those derived from a random sample of tests. However, in the context of avalanches, obtaining such a sample without jeopardizing the safety of observers would be utopian (it would require considering all slopes steeper than 30°, for instance). As a result, this sample cannot be entirely random. To supplement this statistical study, we extended the analysis to the 454 CTs that, once again, differentiated a single weak layer or none at all. However, this time, these tests were conducted for avalanche danger forecasting purposes (see Figure 3). The obtained results are as follows (see It is worth noting that these results are fairly similar to those for the 39 cases mentioned above, but nevertheless show a small but significant decrease of Strong (CT) cases, and an emergence of several Negative (CT) ones. These results are consistent with our explicit intention to systematize the characterization of the most unstable spot within the frequented area and indeed confirm the sought-after heterogeneity within the snowpack prior to conducting each test.

Not represented in the previous tables, which consider the more effective CT, we also extracted statistics regarding the heterogeneity of results between CT1 and CT2. Notable differences were observed in 63.49% of cases. These differences pertained to either the slab thickness, the weak layer thickness, the number of taps performed, or a combination of these metrics.

PSTs measurements

We followed the same statistical approach to analyze the results of the PSTs. Thus, the four classes characterizing their outcomes aim to classify the crack propagation within the weak layer. This classification intersects two components: (i) the critical cut length with the saw and (ii) the arrest condition of the propagation [START_REF] Gauthier | The Propagation Saw Test (PST): A Review of its Development, Applications, and Recent Research[END_REF] (see Table 4). Regarding the critical cut length, note that the term "Epsilon" corresponds to a very small critical length (a few centimeters). Regarding the arrest condition, note that the term "Takeover" implies that propagation is at first incomplete, but then resumes if a new failure is initiated on the remaining block. However, this is not always the case, and the term "Incomplete" is used in such instances. In Table 5, propagation is predominantly characterized as Strong (PST) , even though it's less pronounced compared to the CTs (see Table 2). It's worth noting that all tests not classified as Strong (PST) were conducted at least one day after the avalanche release, suggesting that the weak layer might have evolved, explaining this difference.

Critical cut length

In Table 6, we observe a significant decrease in Strong (PST) cases, even though they remain in the majority, in favor of Negative (PST) cases, and this shift is much more prominent than in the case of the CTs (see Table 3). In agreement with the above statistics, local crack is no guarantee for an efficient propagation in the weak layer, since collapse sizes may be smaller than critical propagation crack sizes [Louchet, 2020]. This clearly demonstrates that the execution of a CT must be complemented by a propagation test, as it remains one of the critical aspects in avalanche danger forecasting.

Figure 4: PST with incomplete propagation

To conclude this statistical study, let's now revisit the relationship between the arrest condition of the propagation and the chosen PST block size (see Section 2.2). In the case of an incomplete propagation (see Figure 4), whether with or without takeover, 70% of the recorded tests demonstrated a propagation arrest beyond the midpoint of the column, i.e. more than 90 cm. This observation validates the extension of our test column to 180 cm to better characterize this phenomenon.

DISSEMINATION AND EXPLOITATION OF RESULTS

Although largely funded by certain "departments" in the French Alps, these tests are intended to be public and are thus disseminated as soon as they are uploaded from the Smartphone application, through https://www.dataavalanche.org/romansns.

Figure 5: Graphical test's results

To enhance interpretability, we have designed a graphical representations for each of the results (see Figure 5). In addition to the test's metadata, all stages of the protocol are visualized in relation to the same layout as our template. CT1 and CT2 are depicted on either side of the graph. The height of the test column, slab thickness, weak layer thickness (in red), and substrate thickness (if any) are shown, along with the number of applied taps. The temperature and stratigraphic profiles are centered, as well as the result from the propagation test. This can take various forms to represent the critical saw-cut length and the propagation arrest condition (see Figure 6):

1. Spontaneous propagation upon block isolation (cable cut).

2.

Complete propagation after a given length of saw cutting.

3.

Incomplete propagation with propagation resumption after a new saw cut.

4.

Incomplete propagation without resumption.

No propagation.

Figure 6: Graphical PST representations All these results are used daily by numerous practitioners, both professionals and amateurs, and are now an integral part of the information system used by three French "departments" (Savoie, Isère, Hautes-Alpes) for securing road access and reopening major Alpine passes at the end of the season. In a broader context, these outcomes provide a solid foundation for estimating one of the six criteria of the CRISTAL approach, namely "a possible buried weak layer" criteria. They are thus disseminated via our online tool SYNTHESIS, which enables easy access and systematic cross-checking of all information essential for avalanche danger assessment. Both CRISTAL and SYNTHESIS are the focus of two additional articles in this ISSW issue.

DISCUSSION

Whether in the applied perspective of avalanche danger forecasting or in the broader analysis of the snowpack and its stability, our protocol still suffers from an insufficient number of tests, both in terms of spatial distribution and over time (543 tests over three seasons The tests conducted following avalanches are a strong point of our database, but they are still too few in number ( 44). Conducting such tests after accidental avalanches has often been done in the context of legal investigations. Opportunities to conduct tests on spontaneous avalanches might be more frequent within the scope of currently funded missions, but they present an additional constraint for already busy observers. Nonetheless, the information obtained from these real avalanche events is of major interest.

From a methodological standpoint, conducting tests outside of predefined permanent sites allows for addressing questions about stratigraphy and stability with a high degree of freedom in relation to current and forecasted snow and weather conditions. However, this approach faces challenges in terms of selecting appropriate locations and interpreting the results. The involvement of guides from the SNGM (National Union of Mountain Guides -France) in the 2020-2021 period demonstrated that a strong training program and ongoing support throughout the season are necessary to produce comprehensive and relevant data, even for professionals.

The arbitrary definition of seven critical cut measures (see Table 4) is practical for field data collection and subsequent statistical analysis, but it can suffer from inaccurate estimation and can mask a more complex reality.

CONCLUSION & PERSPECTIVES

Our protocol, now formalized and fully equipped, is being used in a formal and sustainable manner. For example, it is applied in the context of ongoing risk management for avalanche hazard on roads in three French Alpine "departments".

Its effectiveness has been recognized in crisis management as well as in decisions to conduct (or not) preventive avalanche control operations. The protocol is also integrated into the training of professionals such as French ski instructors, both as field practice and as an examination topic.

The formalized protocol is designed to improve avalanche danger assessment through four objectives: (i) detect the presence of one or more weak layers, by conducting CTs; (ii) assess the heterogeneity of the snowpack, by comparing CT1 and CT2, located on either side of the trench; (iii) characterize the propensity of a local crack to propagate in the identified weak layer by conducting a PST using a modified template of 180 cm, in order to better characterize arrest condition; (iv) characterize the different snowpack layers throughout its thickness, by systematically producing a stratigraphic profile. For this purpose, the trench design was defined according to a precise template, ensuring protocol reproducibility. The location of each test trench is expertly determined to choose the spot where stratigraphy seems to be the most unstable. All these steps are facilitated by a Smartphone application that guides users through the protocol, streamlines data entry, and ensures the long-term storage of results on the data-avalanche association's server. Our efforts have also led us to develop a novel graphical representation of test results, making them easier to analyze, comprehend, and share.

A statistical analysis of the results initially demonstrated the consistency of the protocol when applied to recent avalanches. It also highlighted points that still suffer uncertainties.

For instance, it becomes evident that an easy local crack after the failure initiation (CT) is not consistently linked to a complete propagation within the weak layer (positive PST or ECT).

From a perspective of avalanche risk estimation, it appears that relying only on a CT is insufficient.

One of the limitations still inherent in our protocol is the relatively small number of tests conducted (543 over three seasons). For this reason, we started working on the spatial extrapolation of each test. The goal is to determine their geographic significance (altitude and exposure range, topography, etc.) and their scale (slope, sector, mountain range, department, etc.). This probabilistic extrapolation should ultimately enable better avalanche hazard prediction, even with a small number of tests.

Figure 1 :

 1 Figure 1: Protocol trench template and tests combination

Figure

  Figure 2: Smartphone App

Figure 3 :

 3 Figure 3: Sample of tests constituting our database

Table 2 :

 2 Classification of 39 CTs related to recent avalanches (with a single weak layer)

				upon block
			isolation or 1 to 3 taps
	Moderate (CT)	4 to 6 taps
	Slight (CT)		7 to 9 taps
	Negative (CT)	10 or more taps or no crack
	Table 1: CT local crack classification
	Considering the more effective CT (between CT1
	and CT2), we obtained the following results (see
	Table 2):
	Strong (CT)	Moderate (CT) Slight (CT)	Negative (CT)
	92.31 %		5.13 %	2.56 %	0.00 %

The CT was classified as Strong (CT) in 92,31% of cases. Only 5.13% of cases were classified as Moderate (CT) , corresponding to 2 tests. In the first one, a very thin temporary weak layer

Table 3 )

 3 :

	Strong (CT)	Moderate (CT) Slight (CT)	Negative (CT)
	85.46 %	9.25 %	1.54 %	3.74 %

Table 3 :

 3 Classification of 454 CTs made for forcasting purposes (with a single weak layer)

Table 4 :

 4 PST crack propagation classificationAs shown in Figure3, the first subset considered corresponds to the 39 tests conducted in areas of recent avalanche release (see Table5), and the second subset consists of 440 PSTs conducted for avalanche danger forecasting purposes (see Table6-14 CTs out of the 454 didn't reveal any weak layer).

	Arrest condition

Table 5 :

 5 Classification of 39 PSTs related to recent avalanches (with a single weak layer)

	Strong

(PST) Moderate (PST) Slight (PST) Negative (PST)

	41.36 %	26.14 %	11.82 %	20.68 %

Table 6 :

 6 Classification of 440 PSTs made for forcasting purposes (with a single weak layer)