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Chemical bond

A chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bonds, or some combination of these effects. Chemical bonds are described as having different strengths: there are "strong bonds" or "primary bonds" such as covalent, ionic and metallic bonds, and "weak bonds" or "secondary bonds" such as dipole–dipole interactions, the London dispersion force, and hydrogen bonding.

Since opposite electric charges attract, the negatively charged electrons surrounding the nucleus and the positively charged protons within a nucleus attract each other. Electrons shared between two nuclei will be attracted to both of them. "Constructive quantum mechanical wavefunction interference" stabilizes the paired nuclei (see Theories of chemical bonding). Bonded nuclei maintain an optimal distance (the bond distance) balancing attractive and repulsive effects explained quantitatively by quantum theory.

The atoms in molecules, crystals, metals and other forms of matter are held together by chemical bonds, which determine the structure and properties of matter.

All bonds can be described by quantum theory, but, in practice, simplified rules and other theories allow chemists to predict the strength, directionality, and polarity of bonds. The octet rule and VSEPR theory are examples. More sophisticated theories are valence bond theory, which includes orbital hybridization and resonance, and molecular orbital theory which includes the linear combination of atomic orbitals and ligand field theory. Electrostatics are used to describe bond polarities and the effects they have on chemical substances.

Overview of main types of chemical bonds
A chemical bond is an attraction between atoms. This attraction may be seen as the result of different behaviors of the outermost or valence electrons of atoms. These behaviors merge into each other seamlessly in various circumstances, so that there is no clear line to be drawn between them. However it remains useful and customary to differentiate between different types of bond, which result in different properties of condensed matter.

In the simplest view of a covalent bond, one or more electrons (often a pair of electrons) are drawn into the space between the two atomic nuclei. Energy is released by bond formation. This is not as a result of reduction in potential energy, because the attraction of the two electrons to the two protons is offset by the electron-electron and proton-proton repulsions. Instead, the release of energy (and hence stability of the bond) arises from the reduction in kinetic energy due to the electrons being in a more spatially distributed (i.e. longer de Broglie wavelength) orbital compared with each electron being confined closer to its respective nucleus. These bonds exist between two particular identifiable atoms and have a direction in space, allowing them to be shown as single connecting lines between atoms in drawings, or modeled as sticks between spheres in models.

In a polar covalent bond, one or more electrons are unequally shared between two nuclei. Covalent bonds often result in the formation of small collections of better-connected atoms called molecules, which in solids and liquids are bound to other molecules by forces that are often much weaker than the covalent bonds that hold the molecules internally together. Such weak intermolecular bonds give organic molecular substances, such as waxes and oils, their soft bulk character, and their low melting points (in liquids, molecules must cease most structured or oriented contact with each other). When covalent bonds link long chains of atoms in large molecules, however (as in polymers such as nylon), or when covalent bonds extend in networks through solids that are not composed of discrete molecules (such as diamond or quartz or the silicate minerals in many types of rock) then the structures that result may be both strong and tough, at least in the direction oriented correctly with networks of covalent bonds. Also, the melting points of such covalent polymers and networks increase greatly.

In a simplified view of an ionic bond, the bonding electron is not shared at all, but transferred. In this type of bond, the outer atomic orbital of one atom has a vacancy which allows the addition of one or more electrons. These newly added electrons potentially occupy a lower energy-state (effectively closer to more nuclear charge) than they experience in a different atom. Thus, one nucleus offers a more tightly bound position to an electron than does another nucleus, with the result that one atom may transfer an electron to the other. This transfer causes one atom to assume a net positive charge, and the other to assume a net negative charge. The bond then results from electrostatic attraction between the positive and negatively charged ions. Ionic bonds may be seen as extreme examples of polarization in covalent bonds. Often, such bonds have no particular orientation in space, since they result from equal electrostatic attraction of each ion to all ions around them. Ionic bonds are strong (and thus ionic substances require high temperatures to melt) but also brittle, since the forces between ions are short-range and do not easily bridge cracks and fractures. This type of bond gives rise to the physical characteristics of crystals of classic mineral salts, such as table salt.

A less often mentioned type of bonding is metallic bonding. In this type of bonding, each atom in a metal donates one or more electrons to a "sea" of electrons that reside between many metal atoms. In this sea, each electron is free (by virtue of its wave nature) to be associated with a great many atoms at once. The bond results because the metal atoms become somewhat positively charged due to loss of their electrons while the electrons remain attracted to many atoms, without being part of any given atom. Metallic bonding may be seen as an extreme example of delocalization of electrons over a large system of covalent bonds, in which every atom participates. This type of bonding is often very strong (resulting in the tensile strength of metals). However, metallic bonding is more collective in nature than other types, and so they allow metal crystals to more easily deform, because they are composed of atoms attracted to each other, but not in any particularly-oriented ways. This results in the malleability of metals. The cloud of electrons in metallic bonding causes the characteristically good electrical and thermal conductivity of metals, and also their shiny lustre that reflects most frequencies of white light.

History
Early speculations about the nature of the chemical bond, from as early as the 12th century, supposed that certain types of chemical species were joined by a type of chemical affinity. In 1704, Sir Isaac Newton famously outlined his atomic bonding theory, in "Query 31" of his Opticks, whereby atoms attach to each other by some "force". Specifically, after acknowledging the various popular theories in vogue at the time, of how atoms were reasoned to attach to each other, i.e. "hooked atoms", "glued together by rest", or "stuck together by conspiring motions", Newton states that he would rather infer from their cohesion, that "particles attract one another by some force, which in immediate contact is exceedingly strong, at small distances performs the chemical operations, and reaches not far from the particles with any sensible effect."

In 1819, on the heels of the invention of the voltaic pile, Jöns Jakob Berzelius developed a theory of chemical combination stressing the electronegative and electropositive characters of the combining atoms. By the mid 19th century, Edward Frankland, F.A. Kekulé, A.S. Couper, Alexander Butlerov, and Hermann Kolbe, building on the theory of radicals, developed the theory of valency, originally called "combining power", in which compounds were joined owing to an attraction of positive and negative poles. In 1904, Richard Abegg proposed his rule that the difference between the maximum and minimum valencies of an element is often eight. At this point, valency was still an empirical number based only on chemical properties.

However the nature of the atom became clearer with Ernest Rutherford's 1911 discovery that of an atomic nucleus surrounded by electrons in which he quoted Nagaoka rejected Thomson's model on the grounds that opposite charges are impenetrable. In 1904, Nagaoka proposed an alternative planetary model of the atom in which a positively charged center is surrounded by a number of revolving electrons, in the manner of Saturn and its rings.

Nagaoka's model made two predictions: Rutherford mentions Nagaoka's model in his 1911 paper in which the atomic nucleus is proposed.
 * a very massive atomic center (in analogy to a very massive planet)
 * electrons revolving around the nucleus, bound by electrostatic forces (in analogy to the rings revolving around Saturn, bound by gravitational forces.)

At the 1911 Solvay Conference, in the discussion of what could regulate energy differences between atoms, Max Planck stated: "The intermediaries could be the electrons." These nuclear models suggested that electrons determine chemical behavior.

Next came Niels Bohr's 1913 model of a nuclear atom with electron orbits. In 1916, chemist Gilbert N. Lewis developed the concept of electron-pair bonds, in which two atoms may share one to six electrons, thus forming the single electron bond, a single bond, a double bond, or a triple bond; in Lewis's own words, "An electron may form a part of the shell of two different atoms and cannot be said to belong to either one exclusively."

Also in 1916, Walther Kossel put forward a theory similar to Lewis' only his model assumed complete transfers of electrons between atoms, and was thus a model of ionic bonding. Both Lewis and Kossel structured their bonding models on that of Abegg's rule (1904).

Niels Bohr also proposed a model of the chemical bond in 1913. According to his model for a diatomic molecule, the electrons of the atoms of the molecule form a rotating ring whose plane is perpendicular to the axis of the molecule and equidistant from the atomic nuclei. The dynamic equilibrium of the molecular system is achieved through the balance of forces between the forces of attraction of nuclei to the plane of the ring of electrons and the forces of mutual repulsion of the nuclei. The Bohr model of the chemical bond took into account the Coulomb repulsion – the electrons in the ring are at the maximum distance from each other.

In 1927, the first mathematically complete quantum description of a simple chemical bond, i.e. that produced by one electron in the hydrogen molecular ion, H2+, was derived by the Danish physicist Øyvind Burrau. This work showed that the quantum approach to chemical bonds could be fundamentally and quantitatively correct, but the mathematical methods used could not be extended to molecules containing more than one electron. A more practical, albeit less quantitative, approach was put forward in the same year by Walter Heitler and Fritz London. The Heitler–London method forms the basis of what is now called valence bond theory. In 1929, the linear combination of atomic orbitals molecular orbital method (LCAO) approximation was introduced by Sir John Lennard-Jones, who also suggested methods to derive electronic structures of molecules of F2 (fluorine) and O2 (oxygen) molecules, from basic quantum principles. This molecular orbital theory represented a covalent bond as an orbital formed by combining the quantum mechanical Schrödinger atomic orbitals which had been hypothesized for electrons in single atoms. The equations for bonding electrons in multi-electron atoms could not be solved to mathematical perfection (i.e., analytically), but approximations for them still gave many good qualitative predictions and results. Most quantitative calculations in modern quantum chemistry use either valence bond or molecular orbital theory as a starting point, although a third approach, density functional theory, has become increasingly popular in recent years.

In 1933, H. H. James and A. S. Coolidge carried out a calculation on the dihydrogen molecule that, unlike all previous calculation which used functions only of the distance of the electron from the atomic nucleus, used functions which also explicitly added the distance between the two electrons. With up to 13 adjustable parameters they obtained a result very close to the experimental result for the dissociation energy. Later extensions have used up to 54 parameters and gave excellent agreement with experiments. This calculation convinced the scientific community that quantum theory could give agreement with experiment. However this approach has none of the physical pictures of the valence bond and molecular orbital theories and is difficult to extend to larger molecules.

Bonds in chemical formulas
Because atoms and molecules are three-dimensional, it is difficult to use a single method to indicate orbitals and bonds. In molecular formulas the chemical bonds (binding orbitals) between atoms are indicated in different ways depending on the type of discussion. Sometimes, some details are neglected. For example, in organic chemistry one is sometimes concerned only with the functional group of the molecule. Thus, the molecular formula of ethanol may be written in conformational form, three-dimensional form, full two-dimensional form (indicating every bond with no three-dimensional directions), compressed two-dimensional form (CH3–CH2–OH), by separating the functional group from another part of the molecule (C2H5OH), or by its atomic constituents (C2H6O), according to what is discussed. Sometimes, even the non-bonding valence shell electrons (with the two-dimensional approximate directions) are marked, e.g. for elemental carbon .'C'. Some chemists may also mark the respective orbitals, e.g. the hypothetical ethene−4 anion (\/C=C/\ −4) indicating the possibility of bond formation.

Strong chemical bonds
Strong chemical bonds are the intramolecular forces that hold atoms together in molecules. A strong chemical bond is formed from the transfer or sharing of electrons between atomic centers and relies on the electrostatic attraction between the protons in nuclei and the electrons in the orbitals.

The types of strong bond differ due to the difference in electronegativity of the constituent elements. Electronegativity is the tendency for an atom of a given chemical element to attract shared electrons when forming a chemical bond, where the higher the associated electronegativity then the more it attracts electrons. Electronegativity serves as a simple way to quantitatively estimate the bond energy, which characterizes a bond along the continuous scale from covalent to ionic bonding. A large difference in electronegativity leads to more polar (ionic) character in the bond.

Ionic bond
Ionic bonding is a type of electrostatic interaction between atoms that have a large electronegativity difference. There is no precise value that distinguishes ionic from covalent bonding, but an electronegativity difference of over 1.7 is likely to be ionic while a difference of less than 1.7 is likely to be covalent. Ionic bonding leads to separate positive and negative ions. Ionic charges are commonly between −3e to +3e. Ionic bonding commonly occurs in metal salts such as sodium chloride (table salt). A typical feature of ionic bonds is that the species form into ionic crystals, in which no ion is specifically paired with any single other ion in a specific directional bond. Rather, each species of ion is surrounded by ions of the opposite charge, and the spacing between it and each of the oppositely charged ions near it is the same for all surrounding atoms of the same type. It is thus no longer possible to associate an ion with any specific other single ionized atom near it. This is a situation unlike that in covalent crystals, where covalent bonds between specific atoms are still discernible from the shorter distances between them, as measured via such techniques as X-ray diffraction.

Ionic crystals may contain a mixture of covalent and ionic species, as for example salts of complex acids such as sodium cyanide, NaCN. X-ray diffraction shows that in NaCN, for example, the bonds between sodium cations (Na+) and the cyanide anions (CN−) are ionic, with no sodium ion associated with any particular cyanide. However, the bonds between the carbon (C) and nitrogen (N) atoms in cyanide are of the covalent type, so that each carbon is strongly bound to just one nitrogen, to which it is physically much closer than it is to other carbons or nitrogens in a sodium cyanide crystal.

When such crystals are melted into liquids, the ionic bonds are broken first because they are non-directional and allow the charged species to move freely. Similarly, when such salts dissolve into water, the ionic bonds are typically broken by the interaction with water but the covalent bonds continue to hold. For example, in solution, the cyanide ions, still bound together as single CN− ions, move independently through the solution, as do sodium ions, as Na+. In water, charged ions move apart because each of them are more strongly attracted to a number of water molecules than to each other. The attraction between ions and water molecules in such solutions is due to a type of weak dipole-dipole type chemical bond. In melted ionic compounds, the ions continue to be attracted to each other, but not in any ordered or crystalline way.

Covalent bond
Covalent bonding is a common type of bonding in which two or more atoms share valence electrons more or less equally. The simplest and most common type is a single bond in which two atoms share two electrons. Other types include the double bond, the triple bond, one- and three-electron bonds, the three-center two-electron bond and three-center four-electron bond.

In non-polar covalent bonds, the electronegativity difference between the bonded atoms is small, typically 0 to 0.3. Bonds within most organic compounds are described as covalent. The figure shows methane (CH4), in which each hydrogen forms a covalent bond with the carbon. See sigma bonds and pi bonds for LCAO descriptions of such bonding.

Molecules that are formed primarily from non-polar covalent bonds are often immiscible in water or other polar solvents, but much more soluble in non-polar solvents such as hexane.

A polar covalent bond is a covalent bond with a significant ionic character. This means that the two shared electrons are closer to one of the atoms than the other, creating an imbalance of charge. Such bonds occur between two atoms with moderately different electronegativities and give rise to dipole–dipole interactions. The electronegativity difference between the two atoms in these bonds is 0.3 to 1.7.

Single and multiple bonds
A single bond between two atoms corresponds to the sharing of one pair of electrons. The Hydrogen (H) atom has one valence electron. Two Hydrogen atoms can then form a molecule, held together by the shared pair of electrons. Each H atom now has the noble gas electron configuration of helium (He). The pair of shared electrons forms a single covalent bond. The electron density of these two bonding electrons in the region between the two atoms increases from the density of two non-interacting H atoms.

A double bond has two shared pairs of electrons, one in a sigma bond and one in a pi bond with electron density concentrated on two opposite sides of the internuclear axis. A triple bond consists of three shared electron pairs, forming one sigma and two pi bonds. An example is nitrogen. Quadruple and higher bonds are very rare and occur only between certain transition metal atoms.

Coordinate covalent bond (dipolar bond)
A coordinate covalent bond is a covalent bond in which the two shared bonding electrons are from the same one of the atoms involved in the bond. For example, boron trifluoride (BF3) and ammonia (NH3) form an adduct or coordination complex F3B←NH3 with a B–N bond in which a lone pair of electrons on N is shared with an empty atomic orbital on B. BF3 with an empty orbital is described as an electron pair acceptor or Lewis acid, while NH3 with a lone pair that can be shared is described as an electron-pair donor or Lewis base. The electrons are shared roughly equally between the atoms in contrast to ionic bonding. Such bonding is shown by an arrow pointing to the Lewis acid. (In the Figure, solid lines are bonds in the plane of the diagram, wedged bonds point towards the observer, and dashed bonds point away from the observer.)

Transition metal complexes are generally bound by coordinate covalent bonds. For example, the ion Ag+ reacts as a Lewis acid with two molecules of the Lewis base NH3 to form the complex ion Ag(NH3)2+, which has two Ag←N coordinate covalent bonds.

Metallic bonding
In metallic bonding, bonding electrons are delocalized over a lattice of atoms. By contrast, in ionic compounds, the locations of the binding electrons and their charges are static. The free movement or delocalization of bonding electrons leads to classical metallic properties such as luster (surface light reflectivity), electrical and thermal conductivity, ductility, and high tensile strength.

Intermolecular bonding
There are several types of weak bonds that can be formed between two or more molecules which are not covalently bound. Intermolecular forces cause molecules to attract or repel each other. Often, these forces influence physical characteristics (such as the melting point) of a substance.

Van der Waals forces are interactions between closed-shell molecules. They include both Coulombic interactions between partial charges in polar molecules, and Pauli repulsions between closed electrons shells.

Keesom forces are the forces between the permanent dipoles of two polar molecules. London dispersion forces are the forces between induced dipoles of different molecules. There can also be an interaction between a permanent dipole in one molecule and an induced dipole in another molecule.

Hydrogen bonds of the form A--H•••B occur when A and B are two highly electronegative atoms (usually N, O or F) such that A forms a highly polar covalent bond with H so that H has a partial positive charge, and B has a lone pair of electrons which is attracted to this partial positive charge and forms a hydrogen bond. Hydrogen bonds are responsible for the high boiling points of water and ammonia with respect to their heavier analogues. In some cases a similar halogen bond can be formed by a halogen atom located between two electronegative atoms on different molecules.

At short distances, repulsive forces between atoms also become important.

Theories of chemical bonding
In the (unrealistic) limit of "pure" ionic bonding, electrons are perfectly localized on one of the two atoms in the bond. Such bonds can be understood by classical physics. The force between the atoms depends on isotropic continuum electrostatic potentials. The magnitude of the force is in simple proportion to the product of the two ionic charges according to Coulomb's law.

Covalent bonds are better understood by valence bond (VB) theory or molecular orbital (MO) theory. The properties of the atoms involved can be understood using concepts such as oxidation number, formal charge, and electronegativity. The electron density within a bond is not assigned to individual atoms, but is instead delocalized between atoms. In valence bond theory, bonding is conceptualized as being built up from electron pairs that are localized and shared by two atoms via the overlap of atomic orbitals. The concepts of orbital hybridization and resonance augment this basic notion of the electron pair bond. In molecular orbital theory, bonding is viewed as being delocalized and apportioned in orbitals that extend throughout the molecule and are adapted to its symmetry properties, typically by considering linear combinations of atomic orbitals (LCAO). Valence bond theory is more chemically intuitive by being spatially localized, allowing attention to be focused on the parts of the molecule undergoing chemical change. In contrast, molecular orbitals are more "natural" from a quantum mechanical point of view, with orbital energies being physically significant and directly linked to experimental ionization energies from photoelectron spectroscopy. Consequently, valence bond theory and molecular orbital theory are often viewed as competing but complementary frameworks that offer different insights into chemical systems. As approaches for electronic structure theory, both MO and VB methods can give approximations to any desired level of accuracy, at least in principle. However, at lower levels, the approximations differ, and one approach may be better suited for computations involving a particular system or property than the other.

Unlike the spherically symmetrical Coulombic forces in pure ionic bonds, covalent bonds are generally directed and anisotropic. These are often classified based on their symmetry with respect to a molecular plane as sigma bonds and pi bonds. In the general case, atoms form bonds that are intermediate between ionic and covalent, depending on the relative electronegativity of the atoms involved. Bonds of this type are known as polar covalent bonds.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

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Cell

Cell most often refers to:
 * Cell (biology), the functional basic unit of life

Cell may also refer to:

Fictional entities

 * Cell (comics), a Marvel comic book character
 * Cell (Dragon Ball), a character in the manga series Dragon Ball

Literature

 * Cell (novel), a 2006 horror novel by Stephen King
 * "Cells", poem, about a hungover soldier in gaol, by Rudyard Kipling
 * The Cell (play), an Australian play by Robert Wales

Music

 * Cell (music), a small rhythmic and melodic design that can be isolated, or can make up one part of a thematic context
 * Cell (American band)
 * Cell (Japanese band)
 * Cell (album), a 2004 album by Plastic Tree
 * Cells, a 1998 album by Cex
 * Cells, a 2012 album by Fake Blood
 * "Cells", an art song composed by G. F. Cobb and named after the poem by Kipling
 * "Cells", a song by Bloem de Ligny
 * "Cells", a song by The Servant
 * The Cells, an American rock band
 * "The Cell" (song), a 2006 song by Jandek

Other arts, entertainment, and media

 * The Cell (film), a 2000 psychological thriller film starring Jennifer Lopez
 * Cell (film), a 2016 film based on the Stephen King novel
 * Animation cel, a transparent sheet on which objects are drawn or painted for traditional, hand-drawn animation
 * "The Cell" (The Vampire Diaries), an episode of the TV series The Vampire Diaries
 * "The Cell" (The Walking Dead), a 2016 television episode of The Walking Dead
 * The Cell (BBC Four), Adam Rutherford's 3-part documentary series that aired on BBC Four
 * The Cell, the original title of the TV series Sleeper Cell

Groups of people

 * Cell, a group of people in a cell group, a form of Christian church organization
 * Clandestine cell, a penetration-resistant form of a secret or outlawed organization
 * Cellular organizational structure, such as in business management

Rooms

 * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery with only a few monks or nuns
 * Prison cell, a room used to hold people in prisons

Computing and telecommunications

 * Cell (EDA), a term used in an electronic circuit design schematics
 * Cell (microprocessor), a microprocessor architecture developed by Sony, Toshiba, and IBM
 * Cell, a unit in a database table or spreadsheet, formed by the intersection of a row and a column
 * Cell, in wireless local area networking standards (including Wi-Fi), a wireless connection within a limited area, referred to as a cell or Basic Service Set
 * Cell, a fixed-length data frame used in the Asynchronous Transfer Mode protocol
 * Cellphone, a phone connected to a cellular network
 * Cell (network), area of radio coverage in a cellular network
 * Memory cell (computing), the basic unit of (volatile or non-volatile) computer memory

Mathematics

 * Cell (geometry), a three-dimensional element, part of a higher-dimensional object
 * Cell, an element of an abstract cell complex
 * Cell, a basic unit of a cellular automaton
 * Cell, an element of a CW complex
 * Cell, a k-face of a simplicial complex

Other uses in science and technology

 * Cell (journal), a scientific journal
 * Electrochemical cell, a device used to convert chemical energy to electrical energy
 * Fuel cell, a device used to convert chemical energy from a fuel like hydrogen to electricity
 * Galvanic cell or voltaic cell, a particular kind of electrochemical cell
 * Photodetector, or photo cell, a sensor which detects light
 * Solar cell, a component of photovoltaic systems used to convert the energy of light into electricity
 * Storm cell, the smallest unit of a storm-producing system

title: Cell


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Climate

Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude, longitude, terrain, altitude, land use and nearby water bodies and their currents.

Climates can be classified according to the average and typical variables, most commonly temperature and precipitation. The most widely used classification scheme was the Köppen climate classification. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it. The major classifications in Thornthwaite's climate classification are microthermal, mesothermal, and megathermal. Finally, the Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region.

Paleoclimatology is the study of ancient climates. Paleoclimatologists seek to explain climate variations for all parts of the Earth during any given geologic period, beginning with the time of the Earth's formation. Since very few direct observations of climate were available before the 19th century, paleoclimates are inferred from proxy variables. They include non-biotic evidence—such as sediments found in lake beds and ice cores—and biotic evidence—such as tree rings and coral. Climate models are mathematical models of past, present, and future climates. Climate change may occur over long and short timescales due to various factors. Recent warming is discussed in terms of global warming, which results in redistributions of biota. For example, as climate scientist Lesley Ann Hughes has written: "a 3 °C [5 °F] change in mean annual temperature corresponds to a shift in isotherms of approximately 300 – in latitude (in the temperate zone) or 500 m in elevation. Therefore, species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones."

Definition
Climate is commonly defined as the weather averaged over a long period. The standard averaging period is 30 years, but other periods may be used depending on the purpose. Climate also includes statistics other than the average, such as the magnitudes of day-to-day or year-to-year variations. The Intergovernmental Panel on Climate Change (IPCC) 2001 glossary definition is as follows:

"'Climate in a narrow sense is usually defined as the 'average weather', or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.'"

The World Meteorological Organization (WMO) describes "climate normals" as "reference points used by climatologists to compare current climatological trends to that of the past or what is considered typical. A climate normal is defined as the arithmetic average of a climate element (e.g. temperature) over a 30-year period. A 30-year period is used as it is long enough to filter out any interannual variation or anomalies such as El Niño–Southern Oscillation, but also short enough to be able to show longer climatic trends."

The WMO originated from the International Meteorological Organization which set up a technical commission for climatology in 1929. At its 1934 Wiesbaden meeting, the technical commission designated the thirty-year period from 1901 to 1930 as the reference time frame for climatological standard normals. In 1982, the WMO agreed to update climate normals, and these were subsequently completed on the basis of climate data from 1 January 1961 to 31 December 1990. The 1961–1990 climate normals serve as the baseline reference period. The next set of climate normals to be published by WMO is from 1991 to 2010. Aside from collecting from the most common atmospheric variables (air temperature, pressure, precipitation and wind), other variables such as humidity, visibility, cloud amount, solar radiation, soil temperature, pan evaporation rate, days with thunder and days with hail are also collected to measure change in climate conditions.

The difference between climate and weather is usefully summarized by the popular phrase "Climate is what you expect, weather is what you get." Over historical time spans, there are a number of nearly constant variables that determine climate, including latitude, altitude, proportion of land to water, and proximity to oceans and mountains. All of these variables change only over periods of millions of years due to processes such as plate tectonics. Other climate determinants are more dynamic: the thermohaline circulation of the ocean leads to a 5 C warming of the northern Atlantic Ocean compared to other ocean basins. Other ocean currents redistribute heat between land and water on a more regional scale. The density and type of vegetation coverage affects solar heat absorption, water retention, and rainfall on a regional level. Alterations in the quantity of atmospheric greenhouse gases (particularly carbon dioxide and methane determines the amount of solar energy retained by the planet, leading to global warming or global cooling. The variables which determine climate are numerous and the interactions complex, but there is general agreement that the broad outlines are understood, at least insofar as the determinants of historical climate change are concerned.

Climate classification
Climate classifications are systems that categorize the world's climates. A climate classification may correlate closely with a biome classification, as climate is a major influence on life in a region. One of the most used is the Köppen climate classification scheme first developed in 1899.

There are several ways to classify climates into similar regimes. Originally, climes were defined in Ancient Greece to describe the weather depending upon a location's latitude. Modern climate classification methods can be broadly divided into genetic methods, which focus on the causes of climate, and empiric methods, which focus on the effects of climate. Examples of genetic classification include methods based on the relative frequency of different air mass types or locations within synoptic weather disturbances. Examples of empiric classifications include climate zones defined by plant hardiness, evapotranspiration, or more generally the Köppen climate classification which was originally designed to identify the climates associated with certain biomes. A common shortcoming of these classification schemes is that they produce distinct boundaries between the zones they define, rather than the gradual transition of climate properties more common in nature.

Paleoclimatology
Paleoclimatology is the study of past climate over a great period of the Earth's history. It uses evidence with different time scales (from decades to millennia) from ice sheets, tree rings, sediments, pollen, coral, and rocks to determine the past state of the climate. It demonstrates periods of stability and periods of change and can indicate whether changes follow patterns such as regular cycles.

Modern
Details of the modern climate record are known through the taking of measurements from such weather instruments as thermometers, barometers, and anemometers during the past few centuries. The instruments used to study weather over the modern time scale, their observation frequency, their known error, their immediate environment, and their exposure have changed over the years, which must be considered when studying the climate of centuries past. Long-term modern climate records skew towards population centres and affluent countries. Since the 1960s, the launch of satellites allow records to be gathered on a global scale, including areas with little to no human presence, such as the Arctic region and oceans.

Climate variability
Climate variability is the term to describe variations in the mean state and other characteristics of climate (such as chances or possibility of extreme weather, etc.) "on all spatial and temporal scales beyond that of individual weather events." Some of the variability does not appear to be caused systematically and occurs at random times. Such variability is called random variability or noise. On the other hand, periodic variability occurs relatively regularly and in distinct modes of variability or climate patterns.

There are close correlations between Earth's climate oscillations and astronomical factors (barycenter changes, solar variation, cosmic ray flux, cloud albedo feedback, Milankovic cycles), and modes of heat distribution between the ocean-atmosphere climate system. In some cases, current, historical and paleoclimatological natural oscillations may be masked by significant volcanic eruptions, impact events, irregularities in climate proxy data, positive feedback processes or anthropogenic emissions of substances such as greenhouse gases.

Over the years, the definitions of climate variability and the related term climate change have shifted. While the term climate change now implies change that is both long-term and of human causation, in the 1960s the word climate change was used for what we now describe as climate variability, that is, climatic inconsistencies and anomalies.

Climate change

Climate change is the variation in global or regional climates over time. It reflects changes in the variability or average state of the atmosphere over time scales ranging from decades to millions of years. These changes can be caused by processes internal to the Earth, external forces (e.g. variations in sunlight intensity) or human activities, as found recently. Scientists have identified Earth's Energy Imbalance (EEI) to be a fundamental metric of the status of global change.

In recent usage, especially in the context of environmental policy, the term "climate change" often refers only to changes in modern climate, including the rise in average surface temperature known as global warming. In some cases, the term is also used with a presumption of human causation, as in the United Nations Framework Convention on Climate Change (UNFCCC). The UNFCCC uses "climate variability" for non-human caused variations.

Earth has undergone periodic climate shifts in the past, including four major ice ages. These consist of glacial periods where conditions are colder than normal, separated by interglacial periods. The accumulation of snow and ice during a glacial period increases the surface albedo, reflecting more of the Sun's energy into space and maintaining a lower atmospheric temperature. Increases in greenhouse gases, such as by volcanic activity, can increase the global temperature and produce an interglacial period. Suggested causes of ice age periods include the positions of the continents, variations in the Earth's orbit, changes in the solar output, and volcanism. However, these naturally caused changes in climate occur on a much slower time scale than the present rate of change which is caused by the emission of greenhouse gases by human activities.

According to the EU's Copernicus Climate Change Service, average global air temperature has passed 1.5C of warming the period from February 2023 to January 2024.

Climate models
Climate models use quantitative methods to simulate the interactions and transfer of radiative energy between the atmosphere, oceans, land surface and ice through a series of physics equations. They are used for a variety of purposes, from the study of the dynamics of the weather and climate system to projections of future climate. All climate models balance, or very nearly balance, incoming energy as short wave (including visible) electromagnetic radiation to the Earth with outgoing energy as long wave (infrared) electromagnetic radiation from the Earth. Any imbalance results in a change in the average temperature of the Earth.

Climate models are available on different resolutions ranging from >100 km to 1 km. High resolutions in global climate models require significant computational resources, and so only a few global datasets exist. Global climate models can be dynamically or statistically downscaled to regional climate models to analyze impacts of climate change on a local scale. Examples are ICON or mechanistically downscaled data such as CHELSA (Climatologies at high resolution for the earth's land surface areas).

The most talked-about applications of these models in recent years have been their use to infer the consequences of increasing greenhouse gases in the atmosphere, primarily carbon dioxide (see greenhouse gas). These models predict an upward trend in the global mean surface temperature, with the most rapid increase in temperature being projected for the higher latitudes of the Northern Hemisphere.

Models can range from relatively simple to quite complex. Simple radiant heat transfer models treat the Earth as a single point and average outgoing energy. This can be expanded vertically (as in radiative-convective models), or horizontally. Finally, more complex (coupled) atmosphere–ocean–sea ice global climate models discretise and solve the full equations for mass and energy transfer and radiant exchange.

title: Climate


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History of the Comoros

The history of the Comoros extends back to about 800–1000 AD when the archipelago was first inhabited. The Comoros have been inhabited by various groups and sultanates throughout this time. France colonised the islands in the 19th century, and they became independent in 1975.

Early inhabitants
There is uncertainty about the early population of Comoros. According to one study of early crops, the islands may have been settled first by South East Asian sailors the same way Madagascar was.

This influx of Austronesian sailors, who had earlier settled nearby Madagascar, arrived in the 8th to 13 centuries CE. They are the source for the earliest archeological evidence of farming in the islands. Crops from archeological sites in Sima are predominantly rice strains of both indica and japonica varieties from Southeast Asia, as well as various other Asian crops like mung bean and cotton. Only a minority of the examined crops were African-derived, like finger millet, African sorghum, and cowpea. The Comoros are believed to be the first site of contact and subsequent admixture between African and Asian populations (earlier than Madagascar). Comorians today still display at most 20% Austronesian admixture.

From around the 15th century AD, Shirazi slave traders established trading ports and brought in slaves from the mainland. In the 16th century, social changes on the East African coast probably linked to the arrival of the Portuguese saw the arrival of a number of Arabs of Hadrami who established alliances with the Shirazis and founded several royal clans.

Over the centuries, the Comoros have been settled by a succession of diverse groups from the coast of Africa, the Persian Gulf, Southeast Asia and Madagascar.

Europeans

Portuguese explorers first visited the archipelago in 1505.

Apart from a visit by the French Parmentier brothers in 1529, for much of the 16th century the only Europeans to visit the islands were Portuguese. British and Dutch ships began arriving around the start of the 17th century and the island of Ndzwani soon became a major supply point on the route to the East Indies. Ndzwani was generally ruled by a single sultan, who occasionally attempted to extend his authority to Mayotte and Mwali; Ngazidja was more fragmented, on occasion being divided into as many as 12 small kingdoms.

Sir James Lancaster's voyage to the Indian Ocean in 1591 was the first attempt by the English to break into the spice trade, which was dominated by the Portuguese. Only one of his four ships made it back from the Indies on that voyage, and that one with a decimated crew of 5 men and a boy. Lancaster himself was marooned by a cyclone on the Comoros. Many of his crew were speared to death by angry islanders although Lancaster found his way home in 1594. (Dalrymple W. 2019; Bloomsbury Publishing ISBN 1635573955).

Both the British and the French turned their attention to the Comoros islands in the middle of the 19th century. The French finally acquired the islands through a cunning mixture of strategies, including the policy of "divide and conquer", chequebook politics and a serendipitous affair between a sultana and a French trader that was put to good use by the French, who kept control of the islands, quelling unrest and the occasional uprising.

William Sunley, a planter and British Consul from 1848 to 1866, was an influence on Anjouan.

French Comoros
France's presence in the western Indian Ocean dates to the early 17th century. The French established a settlement in southern Madagascar in 1634 and occupied the islands of Réunion and Rodrigues; in 1715 France claimed Mauritius (Île de France), and in 1756 Seychelles. When France ceded Mauritius, Rodrigues, and Seychelles to Britain in 1814, it lost its Indian Ocean ports; Reunion, which remained French, did not offer a suitable natural harbor. In 1840 France acquired the island of Nosy-Be off the northwestern coast of Madagascar, but its potential as a port was limited. In 1841 the governor of Reunion, Admiral de Hell, negotiated with Andrian Souli, the Malagasy ruler of Mayotte, to cede Mayotte to France. Mahore offered a suitable site for port facilities, and its acquisition was justified by de Hell on the grounds that if France did not act, Britain would occupy the island.

Although France had established a foothold in Comoros, the acquisition of the other islands proceeded fitfully. At times the French were spurred on by the threat of British intervention, especially on Nzwani, and at other times, by the constant anarchy resulting from the sultans' wars upon each other. In the 1880s, Germany's growing influence on the East African coast added to the concerns of the French. Not until 1908, however, did the four Comoro Islands become part of France's colony of Madagascar and not until 1912 did the last sultan abdicate. Then, a colonial administration took over the islands and established a capital at Dzaoudzi on Mahore. Treaties of protectorate status marked a transition point between independence and annexation; such treaties were signed with the rulers of Njazidja, Nzwani, and Mwali in 1886.

The effects of French colonialism were mixed, at best. Colonial rule brought an end to the institution of Slavery in the Comoros, but economic and social differences between former slaves and free persons and their descendants persisted. Health standards improved with the introduction of modern medicine, and the population increased about 50 percent between 1900 and 1960. France continued to dominate the economy. Food crop cultivation was neglected as French sociétés (companies) established cash crop plantations in the coastal regions. The result was an economy dependent on the exporting of vanilla, ylang-ylang, cloves, cocoa, copra, and other tropical crops. Most profits obtained from exports were diverted to France rather than invested in the infrastructure of the islands. Development was further limited by the colonial government's practice of concentrating public services on Madagascar. One consequence of this policy was the migration of large numbers of Comorans to Madagascar, where their presence would be a long-term source of tension between Comoros and its giant island neighbor. The Shirazi elite continued to play a prominent role as large landowners and civil servants. On the eve of independence, Comoros remained poor and undeveloped, having only one secondary school and practically nothing in the way of national media. Isolated from important trade routes by the opening of the Suez Canal in 1869, having few natural resources, and largely neglected by France, the islands were poorly equipped for independence.

On September 25, 1942, British forces landed in the Comoros, occupying them until October 13, 1946.

In 1946 the Comoro Islands became an overseas department of France with representation in the French National Assembly. The following year, the islands' administrative ties to Madagascar were severed; Comoros established its own customs regime in 1952. A Governing Council was elected in August 1957 on the four islands in conformity with the loi-cadre (enabling law) of June 23, 1956. A constitution providing for internal self-government was promulgated in 1961, following a 1958 referendum in which Comorans voted overwhelmingly to remain a part of France. This government consisted of a territorial assembly having, in 1975, thirty-nine members, and a Governing Council of six to nine ministers responsible to it.

Agreement was reached with France in 1973 for the Comoros to become independent in 1978. On July 6, 1975, however, the Comorian parliament passed a resolution declaring unilateral independence. The deputies of Mayotte abstained.

In 1961 the Comoros was granted autonomous rule and, in 1975, it broke all ties with France and established itself as an independent republic. From the very beginning Mayotte refused to join the new republic and aligned itself even more firmly to the French Republic, but the other islands remained committed to independence. The first president of the Comoros, Ahmed Abdallah Abderemane, did not last long before being ousted in a coup d'état by Ali Soilih, an atheist with an Islamic background.

Soilih began with a set of solid socialist ideals designed to modernize the country. However, the regime faced problems. A French mercenary by the name of Bob Denard, arrived in the Comoros at dawn on 13 May 1978, and removed Soilih from power. Solih was shot and killed during the coup. The mercenaries returned Abdallah to power and the mercenaries were given key positions in government.

In two referendums, in December 1974 and February 1976, the population of Mayotte voted against independence from France (by 63.8% and 99.4% respectively). Mayotte thus remains under French administration, and the Comorian Government has effective control over only Grande Comore, Anjouan, and Mohéli.

Later, French settlers, French-owned companies, and Arab merchants established a plantation-based economy that now uses about one-third of the land for export crops.

Abdallah regime
In 1978, president Ali Soilih, who had a firm anti-French line, was killed and Ahmed Abdallah came to power. Under the reign of Abdallah, Denard was commander of the Presidential Guard (PG) and de facto ruler of the country. He was trained, supported and funded by the white regimes in South Africa (SA) and Rhodesia (now Zimbabwe) in return for permission to set up a secret listening post on the islands. South-African agents kept an ear on the important ANC bases in Lusaka and Dar es Salaam and watched the war in Mozambique, in which SA played an active role. The Comoros were also used for the evasion of arms sanctions.

When in 1981 François Mitterrand was elected president Denard lost the support of the French intelligence service, but he managed to strengthen the link between SA and the Comoros. Besides the military, Denard established his own company SOGECOM, for both the security and construction, and seemed to profit by the arrangement. Between 1985 and 1987 the relationship of the PG with the local Comorians became worse.

At the end of the 1980s the South Africans did not wish to continue to support the mercenary regime and France was in agreement. Also President Abdallah wanted the mercenaries to leave. Their response was a (third) coup resulting in the death of President Abdallah, in which Denard and his men were probably involved. South Africa and the French government subsequently forced Denard and his mercenaries to leave the islands in 1989.

1989–1996
Said Mohamed Djohar became president. His time in office was turbulent, including an impeachment attempt in 1991 and a coup attempt in 1992.

On September 28, 1995 Bob Denard and a group of mercenaries took over the Comoros islands in a coup (named operation Kaskari by the mercenaries) against President Djohar. France immediately and severely denounced the coup, and backed by the 1978 defense agreement with the Comoros, President Jacques Chirac ordered his special forces to retake the island. Bob Denard began to take measures to stop the coming invasion. A new presidential guard was created. Strong points armed with heavy machine guns were set up around the island, particularly around the island's two airports.

On October 3, 1995, 11 p.m., the French deployed 600 men against a force of 33 mercenaries and a 300-man dissident force. Denard however ordered his mercenaries not to fight. Within 7 hours the airports at Iconi and Hahaya and the French Embassy in Moroni were secured. By 3:00 p.m. the next day Bob Denard and his mercenaries had surrendered. This (response) operation, codenamed Azalée, was remarkable, because there were no casualties, and just in seven days, plans were drawn up and soldiers were deployed. Denard was taken to France and jailed. Prime minister Caambi El-Yachourtu became acting president until Djohar returned from exile in January, 1996. In March 1996, following presidential elections, Mohamed Taki Abdoulkarim, a member of the civilian government that Denard had tried to set up in October 1995, became president. On 23 November 1996, Ethiopian Airlines Flight 961 crashed near a beach on the island after it was hijacked and ran out of fuel killing 125 people and leaving 50 survivors.

Secession of Anjouan and Mohéli
In 1997, the islands of Anjouan and Mohéli declared their independence from the Comoros. A subsequent attempt by the government to re-establish control over the rebellious islands by force failed, and presently the African Union is brokering negotiations to effect a reconciliation. This process is largely complete, at least in theory. According to some sources, Mohéli did return to government control in 1998. In 1999, Anjouan had internal conflicts and on August 1 of that year, the 80-year-old first president Foundi Abdallah Ibrahim resigned, transferring power to a national coordinator, Said Abeid. The government was overthrown in a coup by army and navy officers on August 9, 2001. Mohamed Bacar soon rose to leadership of the junta that took over and by the end of the month he was the leader of the country. Despite two coup attempts in the following three months, including one by Abeid, Bacar's government remained in power, and was apparently more willing to negotiate with the Comoros. Presidential elections were held for all of the Comoros in 2002, and presidents have been chosen for all three islands as well, which have become a confederation. Most notably, Mohammed Bacar was elected for a 5-year term as president of Anjouan. Grande Comore had experienced troubles of its own in the late 1990s, when President Taki died on November 6, 1998. Colonel Azali Assoumani became president following a military coup in 1999. There have been several coup attempts since, but he gained firm control of the country after stepping down temporarily and winning a presidential election in 2002.

In May 2006, Ahmed Abdallah Sambi was elected from the island of Anjouan to be the president of the Union of the Comoros. He is a Sunni cleric who studied in the Sudan, Iran and Saudi Arabia. He is nicknamed "Ayatollah" due to his time in Iran and his penchant for turbans.

Azali Assoumani in power since 2016
Azali Assoumani is a former army officer, first came to power in a coup in 1999. Then he won presidency in 2002 election, having power until 2006. After ten years, he was elected again in 2016 election. In March 2019, he was re-elected in the elections opposition claimed to be full of irregularities.

Before the 2019 election president Azali Assoumani had arranged a constitutional referendum in 2018 that approved extending the presidential mandate from one five-year term to two. The opposition had boycotted the referendum.

In January 2020, his party The Convention for the Renewal of the Comoros (CRC) won 20 out of 24 parliamentary seats in the parliamentary election.

On 18 February 2023 the Comoros assumed the presidency of the African Union. In January 2024, President Azali Assoumani was re-elected with 63% of the vote in the disputed presidential election.

title: History of the Comoros


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Geography of the Comoros

The Comoros archipelago consists of four main islands aligned along a northwest–southeast axis at the north end of the Mozambique Channel, between Mozambique and the island of Madagascar. Still widely known by their French names, the islands officially have been called by their Swahili names by the Comorian government. They are Grande Comore (Njazidja), Mohéli (Mwali), Anjouan (Nzwani), and Mayotte (Mahoré). The islands' distance from each other—Grande Comore is some 200 kilometers from Mayotte, forty kilometers from Mohéli, and eighty kilometers from Anjouan—along with a lack of good harbor facilities, make transportation and communication difficult. Comoros are sunny islands.

Details
The islands have a total land area of 2,236 square kilometers (including Mayotte), and claim territorial waters of 320 square kilometers. Mount Karthala (2316 m) on Grande Comore is an active volcano. From April 17 to 19, 2005, the volcano began spewing ash and gas, forcing as many as 10,000 people to flee. Comoros is located within the Somali plate.

Grande Comore
Grande Comore is the largest island, sixty-seven kilometers long and twenty-seven kilometers wide, with a total area of 1,146 square kilometers. The most recently formed of the four islands in the archipelago, it is also of volcanic origin. Two volcanoes form the island's most prominent topographic features: La Grille in the north, with an elevation of 1,000 meters, is extinct and largely eroded; Kartala in the south, rising to a height of 2,361 meters, last erupted in 1977. A plateau averaging 600 to 700 meters high connects the two mountains. Because Grande Comore is geologically a relatively new island, its soil is thin and rocky and cannot hold water. As a result, water from the island's heavy rainfall must be stored in catchment tanks. There are no coral reefs along the coast, and the island lacks a good harbor for ships. One of the largest remnants of the Comoros' once-extensive rain forests is on the slopes of Kartala. The national capital has been at Moroni since 1962.

Anjouan
Anjouan, triangular shaped and forty kilometers from apex to base, has an area of 424 square kilometers. Three mountain chains — Sima, Nioumakele, and Jimilime—emanate from a central peak, Mtingui (1,575 m), giving the island its distinctive shape. Older than Grande Comore, Anjouan has deeper soil cover, but overcultivation has caused serious erosion. A coral reef lies close to shore; the island's capital of Mutsamudu is also its main port.

Mohéli
Mohéli is thirty kilometers long and twelve kilometers wide, with an area of 290 square kilometers. It is the smallest of the four islands and has a central mountain chain reaching 860 meters at its highest. Like Grande Comore, it retains stands of rain forest. Mohéli's capital is Fomboni.

Mayotte
Mayotte, geologically the oldest of the four islands, is thirty-nine kilometers long and twenty-two kilometers wide, totaling 375 square kilometers, and its highest points are between 500 and 600 meters above sea level. Because of greater weathering of the volcanic rock, the soil is relatively rich in some areas. A well-developed coral reef that encircles much of the island ensures protection for ships and a habitat for fish. Dzaoudzi, capital of the Comoros until 1962 and now Mayotte's administrative center, is situated on a rocky outcropping off the east shore of the main island. Dzaoudzi is linked by a causeway to le Pamanzi, which at ten kilometers in area is the largest of several islets adjacent to Mayotte. Islets are also scattered in the coastal waters of Mayotte just as in Grande Comore, Anjouan, and Mohéli.

Flora and fauna
Comorian waters are the habitat of the coelacanth, a rare fish with limblike fins and a cartilaginous skeleton, the fossil remains of which date as far back as 400 million years and which was once thought to have become extinct about 70 million years ago. A live specimen was caught in 1938 off southern Africa; other coelacanths have since been found in the vicinity of the Comoro Islands.

Several mammals are unique to the islands themselves. Livingstone's fruit bat, although plentiful when discovered by explorer David Livingstone in 1863, has been reduced to a population of about 120, entirely on Anjouan. The world's largest bat, the jet-black Livingstone fruit bat has a wingspan of nearly two meters. A British preservation group sent an expedition to the Comoros in 1992 to bring some of the bats to Britain to establish a breeding population.

A hybrid of the common brown lemur (Eulemur fulvus) originally from Madagascar, was introduced by humans prior to European colonization and is found on Mayotte. The mongoose lemur (Eulemur mongoz), also introduced from Madagascar by humans, can be found on the islands of Mohéli and Anjouan.

22 species of bird are unique to the archipelago and 17 of these are restricted to the Union of the Comoros. These include the Karthala scops-owl, Anjouan scops-owl and Humblot's flycatcher.

Partly in response to international pressures, Comorians in the 1990s have become more concerned about the environment. Steps are being taken not only to preserve the rare fauna, but also to counteract degradation of the environment, especially on densely populated Anjouan. Specifically, to minimize the cutting down of trees for fuel, kerosene is being subsidized, and efforts are being made to replace the loss of the forest cover caused by ylang-ylang distillation for perfume. The Community Development Support Fund, sponsored by the International Development Association (IDA, a World Bank affiliate) and the Comorian government, is working to improve water supply on the islands as well.

Climate
The climate is marine tropical, with two seasons: hot and humid from November to April, the result of the northeastern monsoon, and a cooler, drier season the rest of the year. Average monthly temperatures range from 23 to 28 °C along the coasts. Although the average annual precipitation is 2000 mm, water is a scarce commodity in many parts of the Comoros. Mohéli and Mayotte possess streams and other natural sources of water, but Grande Comore and Anjouan, whose mountainous landscapes retain water poorly, are almost devoid of naturally occurring running water. Cyclones, occurring during the hot and wet season, can cause extensive damage, especially in coastal areas. On the average, at least twice each decade houses, farms, and harbor facilities are devastated by these great storms.

Extreme points
This is a list of the extreme points of the Comoros, the points that are farther north, south, east or west than any other location. This list excludes the French-administered island of Mayotte which is claimed by the Comorian government.

 * Northernmost point – unnamed headland north-west of Bangoua Kouni, Grande Comore
 * Easternmost point – unnamed peninsula east of Domoni, Anjouan
 * Southernmost point - unnamed headland on Ile Canzouni, Mohéli
 * Westernmost point - unnamed headland west of Iconi, Grande Comore

Statistics
Area: 2,235 km2

Coastline: 340 km

Climate: tropical marine; rainy season (November to May)

Terrain: volcanic islands, interiors vary from steep mountains to low hills

Elevation extremes: lowest point: Indian Ocean 0 m highest point: Karthala 2,360 m

Natural resources: fish

Land use: arable land: 47.29% permanent crops: 29.55% other: 23.16% (2012 est.)

Irrigated land: 1.3 km2 (2003)

Total renewable water resources: 1.2 km3 (2011)

Freshwater withdrawal (domestic/industrial/agricultural): total: 0.01 km3/yr (48%/5%/47%) per capital: 16.86 m3/yr (1999)

Natural hazards: cyclones possible during rainy season (December to April); volcanic activity on Grand Comore

Environmental - current issues: soil degradation and erosion results from crop cultivation on slopes without proper terracing; deforestation

title: Geography of the Comoros


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Demographics of the Comoros

The Comorians (القمري) inhabiting Grande Comore, Anjouan, and Mohéli (86% of the population) share African-Arab origins. Islam is the dominant religion, and Quranic schools for children reinforce its influence. Although Islamic culture is firmly established throughout, a small minority are Christian.

The most common language is Comorian, related to Swahili. French and Arabic also are spoken. About 89% of the population is literate.

The Comoros have had eight censuses since World War II:
 * 1951
 * 1956
 * 1958-09-07: 183,133
 * 1966-07-06
 * Note: in 1974 Mayotte was removed from the Comoros
 * 1980-09-15: 335,150
 * 1991-09-15: 446,817
 * 2003-09-15: 575,660
 * 2017-12-15: 758,316

The latest official estimate (for 1 July 2020) is 897,219.

Population density figures conceal a great disparity between the republic's most crowded island, Nzwani, which had a density of 772 persons per square kilometer in 2017; Njazidja, which had a density of 331 persons per square kilometer in 2017; and Mwali, where the 2017 population density figure was 178 persons per square kilometer. By comparison, estimates of the population density per square kilometer of the Indian Ocean's other island microstates ranged from 241 (Seychelles) to 690 (Maldives) in 1993. Given the rugged terrain of Njazidja and Nzwani, and the dedication of extensive tracts to agriculture on all three islands, population pressures on the Comoros are becoming increasingly critical.

The age structure of the population of the Comoros is similar to that of many developing countries, in that the republic has a very large proportion of young people. In 1989, 46.4 percent of the population was under fifteen years of age, an above-average proportion even for sub-Saharan Africa. The population's rate of growth was a relatively high 3.5 percent per annum in the mid 1980s, up substantially from 2.0 percent in the mid-1970s and 2.1 percent in the mid-1960s.

In 1983 the Abdallah regime borrowed US$2.85 million from the International Development Association to devise a national family planning program. However, Islamic reservations about contraception made forthright advocacy and implementation of birth control programs politically hazardous, and consequently little was done in the way of public policy.

The Comorian population has become increasingly urbanized in recent years. In 1991 the percentage of Comorians residing in cities and towns of more than 5,000 persons was about 30 percent, up from 25 percent in 1985 and 23 percent in 1980. The Comoros' largest cities were the capital, Moroni, with about 30,000 people, and the port city of Mutsamudu, on the island of Nzwani, with about 20,000 people.

Migration among the various islands is important. Natives of Nzwani have settled in significant numbers on less crowded Mwali, causing some social tensions, and many Nzwani also migrate to Maore. In 1977 Maore expelled peasants from Ngazidja and Nzwani who had recently settled in large numbers on the island. Some were allowed to reenter starting in 1981 but solely as migrant labor.

The number of Comorians living abroad has been estimated at between 80,000 and 100,000; during the colonial period, most of them lived in Tanzania, Madagascar, and other parts of Southeast Africa. The number of Comorians residing in Madagascar was drastically reduced after anti-Comorian rioting in December 1976 in Mahajanga, in which at least 1,400 Comorians were killed. As many as 17,000 Comorians left Madagascar to seek refuge in their native land in 1977 alone. About 100,000 Comorians live in France; many of them had gone there for a university education and never returned. Small numbers of Indians, Malagasy, South Africans, and Europeans (mostly French) live on the islands and play an important role in the economy. Most French left after independence in 1975.

Some Persian Gulf countries started buying Comorian citizenship for their stateless Bedoon residents and deporting them to Comoros.

Vital statistics
Statistics :

Fertility and Births
Total Fertility Rate (TFR) (Wanted Fertility Rate) and Crude Birth Rate (CBR):

Structure of the population (DHS 2012) (Males 11 088, Females 12 284 = 23 373) :

Fertility data as of 2012 (DHS Program):

Other demographic statistics
Demographic statistics according to the World Population Review in 2022.

 * One birth every 19 minutes
 * One death every 85 minutes
 * One net migrant every 288 minutes
 * Net gain of one person every 27 minutes

The following demographic statistics are from the CIA World Factbook.

Population

 * 876,437 (2022 est.)
 * 821,164 (July 2018 est.)
 * 690,948 (July 2006 est.)

Religions
Sunni Muslim 98%, other (including Shia Muslim, Roman Catholic, Jehovah's Witness, Protestant) 2% note: Sunni Islam is the state religion

Age structure

 * 0-14 years: 36.68% (male 154,853/female 155,602)
 * 15-24 years: 20.75% (male 85,208/female 90,422)
 * 25-54 years: 33.99% (male 136,484/female 151,178)
 * 55-64 years: 4.49% (male 17,237/female 20,781)
 * 65 years and over: 4.08% (male 15,437/female 19,079) (2020 est.)

 * 0-14 years: 38.54% (male 157,764 /female 158,676)
 * 15-24 years: 19.89% (male 79,133 /female 84,181)
 * 25-54 years: 33.25% (male 129,645 /female 143,408)
 * 55-64 years: 4.34% (male 15,957 /female 19,690)
 * 65 years and over: 3.98% (male 14,881 /female 17,829) (2018 est.)

 * 0–14 years: 42.7% (male 148,009/female 147,038)
 * 15–64 years: 54.3% (male 185,107/female 190,139)
 * 65 years and over: 3% (male 9,672/female 10,983) (2006 est.)

Population growth rate

 * 1.37% (2022 est.) Country comparison to the world: 70th
 * 1.57% (2018 est.) Country comparison to the world: 66th
 * 2.87% (2006 est.)

Birth rate

 * 22.52 births/1,000 population (2022 est.) Country comparison to the world: 55th
 * 25.3 births/1,000 population (2018 est.) Country comparison to the world: 49th

Death rate

 * 6.55 deaths/1,000 population (2022 est.) Country comparison to the world: 135th
 * 7.1 deaths/1,000 population (2018 est.) Country comparison to the world: 125th

Net migration rate

 * -2.25 migrant(s)/1,000 population (2022 est.) Country comparison to the world: 172nd
 * -2.4 migrant(s)/1,000 population (2017 est.) Country comparison to the world: 168th

Total fertility rate

 * 2.78 children born/woman (2022 est.) Country comparison to the world: 56th
 * 3.21 children born/woman (2018 est.) Country comparison to the world: 46th

Mother's mean age at first birth

 * 23 years (2012 est.)
 * note: median age at first birth among women 25-49

Contraceptive prevalence rate

 * 19.4% (2012)

Dependency ratios
total dependency ratio: 75.5 (2015 est.) youth dependency ratio: 70.5 (2015 est.) elderly dependency ratio: 5.1 (2015 est.) potential support ratio: 19.7 (2015 est.)

Urbanization

 * urban population: 29.9% of total population (2022)
 * rate of urbanization: 2.97% annual rate of change (2020-25 est.)

 * urban population: 29% of total population (2018)
 * rate of urbanization: 2.87% annual rate of change (2015-20 est.)

Sex ratio

 * At birth: 1.03 male(s)/female
 * Under 15 years: 1.01 male(s)/female
 * 15–64 years: 0.97 male(s)/female
 * 65 years and over: 0.88 male(s)/female
 * Total population: 0.99 male(s)/female (2006 est.)

Life expectancy at birth

 * total population: 67.2 years. Country comparison to the world: 192nd
 * male: 64.93 years
 * female: 69.54 years (2022 est.)

 * Total population: 62.33 years
 * Male: 60 years
 * Female: 64.72 years (2006 est.)

HIV/AIDS

 * Adult prevalence rate: 0.12% (2001 est.)
 * People living with HIV/AIDS: NA
 * Deaths: NA

Nationality

 * Noun: Comorian(s)
 * Adjective: Comorian

Languages

 * Arabic (official), French (official), Comorian (official)

Literacy

 * definition: age 15 and over can read and write
 * total population: 58.8%
 * male: 64.6%
 * female: 53% (2018)

 * Definition: age 15 and over who can read and write
 * total population: 77.8% (2015 est.)
 * male: 81.8% (2015 est.)
 * female: 73.7% (2015 est.)

 * Total population: 56.5%
 * Male: 63.6%
 * Female: 49.3% (2003 est.)

School life expectancy (primary to tertiary education)

 * total: 11 years (2014)
 * male: 11 years (2014)
 * female: 11 years (2014)

title: Demographics of the Comoros


text:
Politics of the Comoros

The Politics of the Union of the Comoros take place in a framework of a unitary presidential republic, whereby the President of the Comoros is both head of state and head of government, and of a multi-party system. Executive power is exercised by the government. Legislative power is vested in both the government and parliament. The precolonial legacies of the sultanates linger while the political situation in Comoros has been extremely fluid since the country's independence in 1975, subject to the volatility of coups and political insurrection.

As of 2008, Comoros and Mauritania were considered by US-based organization Freedom House as the only real “electoral democracies” of the Arab World.

Precolonial and colonial political structures
Sultanates in the late nineteenth century used a cyclic age system and hierarchical lineage membership to provide the foundation for participation in the political process. In the capital, "the sultan was assisted by his ministers and by a madjelis, an advisory council composed of elders, whom he consulted regularly". Apart from local administration, the age system was used to include the population in decision making, depending on the scope of the decision being made. For example, the elders of the island of Njazidja held considerable influence on the authority of the sultan. Though sultanates granted rights to their free inhabitants, were provided with warriors during war and taxed the towns under their authority, their definition as a state is open to debate. The islands' incorporation as a province of the colony of Madagascar into the French colonial empire marked the end of the sultanates.

Despite French colonization, Comorans identify first with kinship or regional ties and rarely ever with the central government. This is a lingering effect of the sovereign sultanates of pre-colonial times. French colonial administration was based on a misconception that the sultanates operated as absolute monarchs: district boundaries were the same as the sultanates', multiple new taxes forced men into wage labor on colonial plantations and was reinforced through a compulsory public labor system that had little effect on infrastructure. French policy was hampered by an absence of settlers, effective communication across islands, rough geographical terrain and hostility towards the colonial government. Policies were made to apply to Madagascar as a whole and seldom to the nuances of each province: civil servants were typically Christian, unaware of local customs and unable to speak the local language. The French established the Ouatou Akouba in 1915, a local form of governance based on "customary structures" already in place that attempted to model itself after the age system in place under the sultanates. Their understanding of the elders' council as a corporate group bypassed the reality that there were men "who had accomplished the necessary customary rituals to be accorded the status of elder and thus be eligible to participate in the political process in the village", which effectively rendered the French elders' council ineffective. Though the Ouatou Akouba was disbanded, it resulted in the consolidation and formalization of the age system as access to power in the customary and local government spheres. The French failure to establish a functioning state in the Comoros has had repercussions in the post-independence era.

Post-independence
At independence there were five main political parties: OUDZIMA, UMMA, the Comoro People's Democratic Rally, the Comoro National Liberation Movement and the Socialist Objective Party. The political groups previously known simply as the 'green' and 'white' party became the Rassemblement Démocratique du Peuple Comorien (RDPC) and the Union Démocratique des Comores (UDC), headed by Sayyid Muhammad Cheikh and Sayyid Ibrahim. Members from both parties later merged to form OUDZIMA under the leadership of first president Ahmad Abdallah while dissidents from both created UMMA under the leadership of future president Ali Soilih.

Prince Said Ibrahim took power in 1970 but was democratically elected out of office in 1972 in favor of former French senator Ahmed Abdallah. President Abdallah declared independence for all islands, except Mayotte which remained under French administration, in 1975. The threat of renewed socioeconomic marginalization following the transfer of the capital to Ngazidja in 1962, more than social or cultural differences, underlay the island's subsequent rejection of independence. France withdrew all economic and technical support for the now independent state, which would encourage a revolutionary regime under future president Ali Soilih. French military and financial aid to mercenaries brought Prince Said Mohammed Jaffar to power after the United National Front of the Comoros (FNU) party toppled Abdallah's government. This mercenary coup was unique in that, unlike other coups on the continent, it was "uninspired by any ideological convictions". The Jaffar regime's inefficient distribution of resources and poor mismanagement was shown through the expulsion of French civil servants as well as endemic unemployment and food shortages. The regime used famine as "an opportunity to switch food patronage from France to the World Food Programme's emergency aid".

President Jaffar's ousting by Minister of Defense and Justice, Ali Soilih, brought about the "periode noire" (dark period) of the country; you could vote at 14, most civil servants were dismissed and there was a ban on some Islamic customs. He implemented revolutionary social reforms such as replacing French with Shikomoro, burning down the national archives and nationalizing land. His government received support from Egypt, Iraq and Sudan. Soilih's attacks on religious and customary authority contributed to his eventual ousting through a French-backed coup consisting of mercenaries and ex-politicians who together formed the Politico Military Doctorate.

Abdallah was reinstated and constructed a mercantile state by resuscitating the structures of the colonial era. His establishment of a one party state and intolerance for dissent further alienated civil society from the state. In May 1978 the Comoros were renamed the Islamic Republic of the Comoros and continued strengthening ties with the Arab world which resulted in their joining the Arab League. Abdallah's government sought to reverse Soilih's 'de-sacralization' by re-introducing the grand marriage, declaring Arabic the second official language behind French, and creating the office of the Grand Mufti. The doctorate & compromise government was dissolved, constitutional changes removed succession from a politician and neutralized the post of another possible challenger in abolishing the position of Prime Minister, which effectively cemented a client-patron network by making the civil service position dependent on Abdallah's political base. The Democratic Front's (DF) internal opposition to Abdallah was suppressed through the incarceration of over 600 people allegedly involved in a failed coup attempt. Abdallah then stocked the House of Assembly with loyal clientelist supporters through rigged parliamentary elections. All of these actions effectively consolidated Abdallah's position.

Muhammed Djohar succeeded president Abdallah after his assassination in 1989 but was evacuated by French troops after a failed coup attempt in 1996. The Comoros were led by Muhammed Taki Abd al-Karim beginning in 1996 and he was followed by interim president Said Massunde who eventually gave way to Assoumani Azali. Taki's lack of Arab heritage led to his lack of understanding Nzwani's cultural differences and economic problems, as seen by the establishment of the elders council with only loyal Taki supporters. As a result, the council was ignored by the true elders of the island. After Taki's death, a military coup in 1999, the nation's eighteenth since independence in 1975, installed Azali in to power. Colonel Azali Assoumani seized power in a bloodless coup in April 1999, overthrowing Interim President Tadjidine Ben Said Massounde, who himself had held the office since the death of democratically elected President Mohamed Taki Abdoulkarim in November, 1998. In May 1999, Azali decreed a constitution that gave him both executive and legislative powers. Bowing somewhat to international criticism, Azali appointed a civilian Prime Minister, Bainrifi Tarmidi, in December 1999; however, Azali retained the mantle of Head of State and army Commander. In December 2000, Azali named a new civilian Prime Minister, Hamada Madi, and formed a new civilian Cabinet. When Azali took power he also pledged to step down in April 2000 and relinquish control to a democratically elected president—a pledge with mixed results. Under Mohammed Taki and Assoumani Azali, access to the state was used to support client networks which led to crumbling infrastructure that cultivated in the islands of Nzwani and Mwali declaring independence only to be stopped by French troops. Azali lacked the social obligations required to address the elders and when combined with his gross mismanagement and increasing economic and social dependence on foreign entities, made managing daily life near nonexistent in the state. Therefore, local administrative structures began popping up and drifting away from reliance on the state, funded by remittances from the expatriate community in France.

Azali Assoumani is a former army officer, first came to power in a coup in 1999. Then he won presidency in 2002 election, having power until 2006. After ten years, he was elected again in 2016 election. In March 2019, he was re-elected in the elections opposition claimed to be full of irregularities.

Before the 2019 election president Azali Assoumani had arranged a constitutional referendum in 2018 that approved extending the presidential mandate from one five-year term to two. The opposition had boycotted the referendum.

In January 2020, his party The Convention for the Renewal of the Comoros (CRC) won 20 out of 24 parliamentary seats in the parliamentary election.

On 18 February 2023 the Comoros assumed the presidency of the African Union. In January 2024, President Azali Assoumani was re-elected with 63% of the vote in the disputed presidential election.

The Comoros Islands have experienced five different constitutions.

First Constitution: Federal Islamic Republic of the Comoros, 1978-1989

 * No parliamentary or popular participation
 * Intended to provide unity and promote economic growth.
 * Islands were known as governorates, independent entities with Island Council's and elected governor's that served four year terms, appointed commissioners, and handled the financial and social matters of the island.
 * Offices at the national level and positions of central government were divided among the three islands. Under this constitution, the unicameral government did not represent the islands in a chamber and gave the governors and federal government authority over the islands.
 * Issues under this constitution included an uneven distribution of resources between governorates and the federal government which lead to limited autonomy in the independent management of each island. Foreign aid required approval of the federal executive, further exacerbating this issue.
 * Revised in 1983, 1984, and 1989 which resulted in the elimination of the Prime Minister position.

Second Constitution: Federal Islamic Republic of the Comoros, 1992 - 1999

 * Consulted civil society and political parties. Governors and Island Council's now elected for five year terms, with the latter in charge of the island's finances.
 * Between 30 and 40% of taxes went to the federal budget with the rest proportionately divided among the islands.
 * The Central government was in charge of the armed forces and national policies and could be terminated through a vote of non-confidence in the Federal Assembly, whose members were elected for four years.
 * This constitution created a Senate of equal representation for the islands where members were elected for six year terms and could collectively challenge policy passed by the Federal Assembly.
 * The Constitutional Council oversaw elections and the constitutionality of proceedings in the islands.
 * The Council of Ulenma promoted Islam.
 * Judicial power was independent from the executive and legislative branches.

Third Constitution: The Union of the Comoros, 2001

 * Federal Assembly dissolved
 * President of the Union elected to five year terms and appoints Prime Minister to serve as head of government.
 * President Azali did not elect a head of government and thus was both the head of the state and government. The executive is known as the council of ministers and appointed by the president with each island having their own presidents.
 * Senate replaced with Assembly of the Union – 30 seats and five year terms.
 * Created a supreme court that was elected by the president, the Assembly of the Union, and the assembly of each island.

Fourth Constitution
In a separate nod to pressure to restore civilian rule, the government organized several committees to compose a new constitution, including the August 2000 National Congress and November 2000 Tripartite Commission. The opposition parties initially refused to participate in the Tripartite Commission, but on 17 February, representatives of the government, the Anjouan separatists, the political opposition, and civil society organizations signed a "Framework Accord for Reconciliation in Comoros," brokered by the Organization for African Unity

The accord called for the creation of a new Tripartite Commission for National Reconciliation to develop a "New Comorian Entity" with a new constitution. The new federal Constitution came into effect in 2002; it included elements of consociationalism, including a presidency that rotates every four years among the islands and extensive autonomy for each island. Presidential elections were held in 2002, at which Azali Assoumani was elected president. In April 2004 legislative elections were held, completing the implementation of the new constitution.

The new Union of the Comoros consists of three islands, Grande Comore, Anjouan and Mohéli. Each island has a president, who shares the presidency of the Union on a rotating basis. The president and his vice-presidents are elected for a term of four years. The constitution states that, "the islands enjoy financial autonomy, freely draw up and manage their budgets".

President Assoumani Azali of Grande Comore is the first Union president. President Mohamed Bacar of Anjouan formed his 13-member government at the end of April, 2003.

On 15 May 2006, Ahmed Abdallah Sambi, a cleric and successful businessman educated in Iran, Saudi Arabia and Sudan, was declared the winner of elections for President of the Republic. He is considered a moderate Islamist and is called Ayatollah by his supporters. He beat out retired French air force officer Mohamed Djaanfari and long-time politician Ibrahim Halidi, whose candidacy was backed by Azali Assoumani, the outgoing president.

A referendum took place on May 16, 2009, to decide whether to cut down the government's unwieldy political bureaucracy. 52.7% of those eligible voted, and 93.8% of votes were cast in approval of the referendum. The referendum would cause each island's president to become a governor and the ministers to become councilors.

Autonomous islands
The constitution gives Grande Comore, Anjouan and Mohéli the right to govern most of their own affairs with their own presidents, except the activities assigned to the Union of the Comoros like Foreign Policy, Defense, Nationality, Banking and others. Comoros considers Mayotte, an overseas collectivity of France, to be part of its territory, with an autonomous status

As of 2011, the three autonomous islands are subdivided into 16 prefectures, 54 communes, and 318 villes or villages.

Executive branch
The federal presidency is rotated between the islands' presidents. The Union of the Comoros abolished the position of Prime Minister in 2002. The position of Vice-President of the Comoros was used 2002–2019.
 * President
 * Azali Assoumani
 * 26 May 2016
 * }
 * }

Legislative branch
The Assembly of the Union has 33 seats, 24 elected in single seat constituencies and 9 representatives of the regional assemblies.

Judicial branch
The Supreme Court or Cour Supreme, has two members appointed by the president, two members elected by the Federal Assembly, one by the Council of each island, and former presidents of the republic.

International organization participation
The Comoros are member of the ACCT, ACP, AfDB, AMF, African Union, FAO, G-77, IBRD, ICAO, ICCt (signatory), ICRM, IDA, IDB, IFAD, IFC, IFRCS, ILO, IMF, InOC, Interpol, IOC, ITU, LAS, NAM, OIC, OPCW (signatory), United Nations, UNCTAD, UNESCO, UNIDO, UPU, WCO, WHO, WMO.

title: Politics of the Comoros


text:
Telecommunications in the Comoros

In large part thanks to international aid programs, Moroni has international telecommunications service. Telephone service, however, is largely limited to the islands' few towns.

Overview
Telephones – main lines in use: 5,000 (1995)

Telephones – mobile cellular: 0 (1995)

Telephone system: sparse system of microwave radio relay and HF radiotelephone communication stations domestic: HF radiotelephone communications and microwave radio relay CMDA mobile network (Huri, operated by Comores Telecom) international: HF radiotelephone communications to Madagascar and Réunion

Radio broadcast stations: AM 1, FM 2, shortwave 1 (1998)

Radios: 90,000 (1997)

Television broadcast stations: 0 (1998)

Televisions: 1,000 (1997)

Internet Service Providers (ISPs): 1 (1999)

Country code (Top-level domain): KM

Special projects
In October 2011 the State of Qatar launched a special program for the construction of a wireless network to interconnect the three islands of the archipelago, by means of low cost, repeatable technology. The project has been developed by Qatar University and Politecnico di Torino, under the supervision of prof. Mazen Hasna and prof. Daniele Trinchero, with a major participation of local actors (Comorian Government, NRTIC, University of the Comoros). The project has been referred as an example of technology transfer and Sustainable Inclusion in developing countries

title: Telecommunications in the Comoros


text:
Transport in the Comoros

There are a number of systems of transport in the Comoros. The Comoros possesses 880 km of road, of which 673 km are paved. It has three seaports: Fomboni, Moroni and Moutsamoudou, but does not have a merchant marine, and no longer has any railway network. It has four airports, all with paved runways, one with runways over 2438 m long, with the others having runways shorter than 1523 m.

The isolation of the Comoros had made air traffic a major means of transportation. One of President Abdallah's accomplishments was to make the Comoros more accessible by air. During his administration, he negotiated agreements to initiate or enhance commercial air links with Tanzania and Madagascar. The Djohar regime reached an agreement in 1990 to link Moroni and Brussels by air. By the early 1990s, commercial flights connected the Comoros with France, Mauritius, Kenya, South Africa, Tanzania, and Madagascar. The national airline was Air Comores. Daily flights linked the three main islands, and air service was also available to Mahoré; each island had airstrips. In 1986 the republic received a grant from the French government's CCCE to renovate and expand Hahaya airport, near Moroni. Because of the absence of scheduled sea transport between the islands, nearly all interisland passenger traffic is by air.

More than 99% of freight is transported by sea. Both Moroni on Njazidja and Mutsamudu on Nzwani have artificial harbors. There is also a harbor at Fomboni, on Mwali. Despite extensive internationally financed programs to upgrade the harbors at Moroni and Mutsamudu, by the early 1990s only Mutsamudu was operational as a deepwater facility. Its harbor could accommodate vessels of up to eleven meters' draught. At Moroni, ocean-going vessels typically lie offshore and are loaded or unloaded by smaller craft, a costly and sometimes dangerous procedure. Most freight continues to be sent to Tanzania, Kenya, Reunion, or Madagascar for transshipment to the Comoros. Use of Comoran ports is further restricted by the threat of cyclones from December through March. The privately operated Comoran Navigation Company (Société Comorienne de Navigation) is based in Moroni, and provides services to Madagascar.

Roads serve the coastal areas, rather than the interior, and the mountainous terrain makes surface travel difficult.

title: Transport in the Comoros


text:
Foreign relations of the Comoros

In November 1975, Comoros became the 143rd member of the United Nations. The new nation was defined as consisting of the entire archipelago, despite the fact that France maintains control over Mayotte.

Overview
Comoros also is a member of the African Union, the Arab League, the European Development Fund, the World Bank, the International Monetary Fund, the Indian Ocean Commission, and the African Development Bank.

The government fostered close relationships with the more conservative (and oil-rich) Arab states, such as Saudi Arabia and Kuwait. It frequently received aid from those countries and the regional financial institutions they influenced, such as the Arab Bank for Economic Development in Africa and the Arab Fund for Economic and Social Development. In October 1993, Comoros joined the League of Arab States, after having been rejected when it applied for membership initially in 1977.

Regional relations generally were good. In 1985 Madagascar, Mauritius, and Seychelles agreed to admit Comoros as the fourth member of the Indian Ocean Commission (IOC), an organization established in 1982 to encourage regional cooperation. In 1993 Mauritius and Seychelles had two of the five embassies in Moroni, and Mauritius and Madagascar were connected to the republic by regularly scheduled commercial flights.

In November 1975, Comoros became the 143d member of the UN. In the 1990s, the republic continued to represent Mahoré in the UN. Comoros was also a member of the OAU, the EDF, the World Bank, the IMF, the IOC, and the African Development Bank.

Comoros thus cultivated relations with various nations, both East and West, seeking to increase trade and obtain financial assistance. In 1994, however, it was increasingly facing the need to control its expenditures and reorganize its economy so that it would be viewed as a sounder recipient of investment. Comoros also confronted domestically the problem of the degree of democracy the government was prepared to grant to its citizens, a consideration that related to its standing in the world community.

Diplomatic relations
List of countries which the Comoros maintains diplomatic relations with:

title: Foreign relations of the Comoros


text:
Army of National Development

The Comorian Armed Forces (Armée nationale de développement, AND; lit. 'Army of National Development') are the national military of the Comoros. The armed forces consist of a small standing army and a 500-member police force, as well as a 500-member defense force. A defense treaty with France provides naval resources for protection of territorial waters, training of Comorian military personnel, and air surveillance. France maintains a small troop presence in the Comoros at government request. France maintains a small Navy base and a Foreign Legion Detachment (DLEM) in Mayotte.

Structure
The AND consists of the following components:

 * Comorian Defense Forces
 * Comorian National Gendarmerie
 * National School of the Armed Forces and Gendarmerie
 * Comorian Presidential Guard
 * Comorian Military Health Services
 * Comorian Coast Guard

Equipment inventory

 * FN FAL battle rifle
 * AK-47 assault rifle
 * Type 81 assault rifle
 * NSV HMG
 * RPG-7 anti-tank weapon
 * Mitsubishi L200 pickup truck

Aircraft
Note: The last comprehensive aircraft inventory list was from Aviation Week & Space Technology in 2007.

title: Army of National Development