Suchergebnisse

The availability of forage resources in European Mediterranean areas, subject to cyclical droughts and changing climatic conditions (temperature increase of + 0.6C°/decade, evapotranspiration + 50 mm/decade), has become a major challenge for livestock farming. Following professional organizations seeking INRA and CIRAD's expertise to search for alfalfa ecotypes capable of adaptation, we have been investigating the diversity of behaviors of 100 alfalfa ecotypes from 26 countries according to climatic constraints for the last three years. Key assumptions related to the response diversity in terms of i) survival, ii) productivity, and iii) nutritive composition. Tests were carried out without inputs or irrigation. Ecotypes of three different environments were pre-selected from a previous project with a total of 65 industrial, 25 farm and 10 wild ecotypes. The results obtained depending on rainfall amounts – i.e. favorable in 2012 with > 30 mm/month, and unfavorable in 2013 and 2014 with < 30 mm/month during the plant growth period –, can help us make selections based on biomass and total nitrogen content. Under rainfall deficit conditions results show: • A marked drop in the productivity of industrial ecotypes due to their sensitivity, the variation of the dry matter is, in 2012-2013: - 25% ± 0.024; in 2012-2014: - 62% ± 0.015; in 2013-2014: - 46% ± 0.044; • Resilience of farm and wild ecotypes highlighting a more interesting genetic variability for selection purposes; • Changes in the earliness/maturity of the various ecotypes, which revealed opportunities to improve animal feed production (grazing periods, cutting dates.); • An opportunity to integrate some ecotypes in multi-specific mixtures. (Texte intégral)

Latin American and Caribbean countries, including Colombia and Guatemala are in the most vulnerable to climate change. Since much of its population is in the highest parts of the mountains, where water scarcity problems are expected, and instability of soils and on the coasts, where the sea level rise and flooding can affect human settlements and key economic activities. It also has a high recurrence of extreme events, with a large and growing technical impact of climate-related emergency [1]. It's necessary know the historical records of those elements to build mitigation of the negative effects of environmental crisis. However, it has been different advance efforts among stake holders as civil society, academia, government and private sector. As is the case of the Institute of Mining and Geotechnical Glückauf-Verlag of Germany and the British Petroleum Company, which developed the Energy and Climate 21 (EC21) software. The concentrations carbon dioxide in the atmosphere to increase considerably in the last 175 years from 280 ppm (parts per million from 1830 to 380 ppm in 2005) [2]. Under this dynamics, modeling was developed to Colombia with parameters of software with EC21, in order to see the scenario in the medium and long-term CO 2 concentrations and temperature increase. And regional plans and visualizing what challenges the country in action lines mitigation and compensation to the effects of climate change.

International audience ; This paper presents an analysis of natural and anthopogenic factors responsible for increasing sanding up and desertifciation phenomena in southeastern Morocco. The results revealed that the environment has changed inthis region over the last few decades via the influence and interaction of different natural and anthropogenic factors. In this very fragile environment, human pressure, altering climatic conditions and the use of inappropriate technology have prompted a long and insidious process leading to the appearance of desert biotopes, even in previous non-desert areas. Increasing populations and socioeconomic changes are responsible for overuse of this environment. A new relationship between human and the environment has developped through the introduction of modern lifestyle in oasis areas, accompanied by increased road systems, irrigation canals, motorization, dams, etc. With this modernization, traditional techniques are becoming obsolete and out of line with development policies. This has led to a generally unbalanced situation. The main environmental changes that have occured such as sanding up and desertification, are therefore more due to human pressure and accompanying technological modifications, along with resource mismanagement, than to unfavorable climatic conditions. Human activities are therefore chiefly responsible for the environmental imbalance that has occured in southeastern Morocco in recent decades. ; Dans cet article nous avons procédé à une analyse des facteurs naturels et anthropiques à l'origine de l'exacerbation des phénomènes d'ensablement et de désertification dans le Sud-Est marocain. Ul s'avère que le milieu a évolué ces dernières décades sous l'influence et l'interaction de divers facteurs anthropiques et naturels. Ainsi, de par ses caractéristiques physiques, ce milieu est naturellement fragile, mais c'est surtout la forte pression humaine alliée à la péjoration des conditions climatiques enregistrée ces dernières décades et l'introduction de technologies lourdes et inappropriées qui ont conduit par de lents processus insidieux à l'apparition de biotopes désertiques même là où il n'y en avait pas. En effet, du fait de l'accroissement de la population et des mutations socio-économiques, on a eu tendance à demander à ce milieu plus qu'il ne peut donner. L'intrusion du monde moderne dans les oasis, qui s'est accompagnée de l'extension du réseau routier, de canaux d'irrigation, de la motorisation, de l'implantation de barrages, etc. a créé de nouveaux rapports entre l'homme et son milieu. La confrontation des techniques modernes et traditionnelles voit ces dernières devenir désuètes, non crédibles et mal adaptées aux nouvelles données des politiques de développement. La situation qui en a résulté est celle d'un déséquilibre généralisé. La recrudescence des phénomènes d'ensablement et de désertification dans le Sud-Est marocain est donc beaucoup plus liée à l'accroissement de la pression humaine, aux transformations technologiques qui l'accompagnent, à une mauvaise gestion des ressources qu'à la péjoration des conditions climatiques peu favorable. Les ,actions humaines sont donc au premier rang des causes des déséquilibres observés ces dernières décennies dans le Sud-Est marocain.

International audience ; This paper presents an analysis of natural and anthopogenic factors responsible for increasing sanding up and desertifciation phenomena in southeastern Morocco. The results revealed that the environment has changed inthis region over the last few decades via the influence and interaction of different natural and anthropogenic factors. In this very fragile environment, human pressure, altering climatic conditions and the use of inappropriate technology have prompted a long and insidious process leading to the appearance of desert biotopes, even in previous non-desert areas. Increasing populations and socioeconomic changes are responsible for overuse of this environment. A new relationship between human and the environment has developped through the introduction of modern lifestyle in oasis areas, accompanied by increased road systems, irrigation canals, motorization, dams, etc. With this modernization, traditional techniques are becoming obsolete and out of line with development policies. This has led to a generally unbalanced situation. The main environmental changes that have occured such as sanding up and desertification, are therefore more due to human pressure and accompanying technological modifications, along with resource mismanagement, than to unfavorable climatic conditions. Human activities are therefore chiefly responsible for the environmental imbalance that has occured in southeastern Morocco in recent decades. ; Dans cet article nous avons procédé à une analyse des facteurs naturels et anthropiques à l'origine de l'exacerbation des phénomènes d'ensablement et de désertification dans le Sud-Est marocain. Ul s'avère que le milieu a évolué ces dernières décades sous l'influence et l'interaction de divers facteurs anthropiques et naturels. Ainsi, de par ses caractéristiques physiques, ce milieu est naturellement fragile, mais c'est surtout la forte pression humaine alliée à la péjoration des conditions climatiques enregistrée ces dernières décades et l'introduction de technologies lourdes et inappropriées qui ont conduit par de lents processus insidieux à l'apparition de biotopes désertiques même là où il n'y en avait pas. En effet, du fait de l'accroissement de la population et des mutations socio-économiques, on a eu tendance à demander à ce milieu plus qu'il ne peut donner. L'intrusion du monde moderne dans les oasis, qui s'est accompagnée de l'extension du réseau routier, de canaux d'irrigation, de la motorisation, de l'implantation de barrages, etc. a créé de nouveaux rapports entre l'homme et son milieu. La confrontation des techniques modernes et traditionnelles voit ces dernières devenir désuètes, non crédibles et mal adaptées aux nouvelles données des politiques de développement. La situation qui en a résulté est celle d'un déséquilibre généralisé. La recrudescence des phénomènes d'ensablement et de désertification dans le Sud-Est marocain est donc beaucoup plus liée à l'accroissement de la pression humaine, aux transformations technologiques qui l'accompagnent, à une mauvaise gestion des ressources qu'à la péjoration des conditions climatiques peu favorable. Les ,actions humaines sont donc au premier rang des causes des déséquilibres observés ces dernières décennies dans le Sud-Est marocain.

"Climate change and international migration flows are phenomena which attract a great deal of attention from policymakers, researchers and the general public around the globe. Are these two phenomena related? Is migration an adaptation strategy to sudden or gradual changes in climate? In this paper our aim is to investigate whether countries that are affected by climatic anomalies with respect to long-term mean experience, ceteris paribus, larger outmigration flows toward rich OECD countries in the period 1990-2001. Contrarily to the bulk of existing studies we use a macro approach and analyse the determinants of international bilateral migration flows employing an augmented gravity-like equation and test the relevance of climate anomalies with respect to long-term average temperature and precipitation. One important novelty in our approach is the explicit consideration in the empirical analysis of the heterogeneous nature of climate shocks, i.e. positive vs. negative variations of temperature and precipitations; non linear and threshold effects of climate shocks. Our results show that the occurrence of climate anomalies in origin countries might have heterogeneous impacts on cross-border outmigration flows depending on the type and size of the shocks and on certain socio-economic characteristics of the country (level of development, past immigration history, vulnerability of the agricultural sector). In general, countries with a higher level of development and with a growing share of irrigated agricultural land are less sensitive to climate anomalies. Interestingly we find that the existence of a network of established migrants plays a complex role. In fact, in case of certain climate shocks - such as non-extreme temperature anomalies and positive precipitation anomalies of large size - networks makes origin countries more resilient to climate shocks; hence they help affected countries to cope with climate shocks (for instance through remittance inflows as documented in other studies). We also find that in case of other climatic events - negative precipitation anomalies and extreme temperature anomalies – the existence of a large network of migrants is positively related with the subsequent size of international migration outflow. Although the analysis conducted is far from being conclusive on the complex relationship between climate change and migration, it offers interesting insights and calls for complementary methodological approaches." [author's abstract]

This book explores the establishment of emissions trading as a form of environmental, market-based governance. It conceptualizes markets as institutions, and analyzes them as a system of climate governance. To this end, it argues that international efforts to promulgate markets run up against local cultures of markets that shape economic practices and knowledge to different degrees. The book also examines the material implications of emissions markets on the environment and climatic systems. In sum, the study finds that cultures of markets present a substantial challenge to a universalist prescription for resolving climate change and highlights issues at the interface of political and economic governance in different political economies. This includes issues of citizen, state, and industry participation, and the materiality of economic and financial productivity

Introduction / by Gordon Bronitsky -- Ecology, economics, and evolutionary explanation in economic prehistory / by Donald L. Hardesty -- An economic model of settlement aggregation and dispersal / by W. Frederick Limp -- The use of climatic data in ecological models / by Judith A. Rasson -- Site catchment analysis and hunter-gatherer resource use / by Marek Zvelebil -- Optimum diet models and return rate curves / by Stephen M. Perlman -- Economic change in the Rio Grande Valley / by Gordon Bronitsky -- Resource uncertainty and buffering strategies in an arid, marginal environment / by Kent Lightfoot -- Intensification and exchange : an evolutionary model of non-egalitarian socio-political organization for the prehistoric plateau Southwest / by Steadman Upham -- Comments on modeling and testing in archaeology / by Mark N. Cohen -- The political economy of resource management / by Stanton W. Green and Kenneth E. Sassaman

Lakes and reservoirs are an important sources of drinking water for human life. However, numerous water quality indexes show seasonal fluctuation under different climatic conditions. We conducted a one-year investigation of Taiping Lake in year 2022 to construct relationship between water quality parameters and water quality. High water temperature promotes the growth of algae, and the existence of N species could provide the essential nutrient substance for the growing of algae. Under the irradiation of sunlight, algae will consume carbon dioxide through photosynthesis and release oxygen which can raise oxygen levels in the water. However, the rapid growth of algae could influence the acid-base balance in water through the consumption of carbon dioxide; thus, resulting in the increasing of pH values. These pH changes may pose a threat to drinking water.

The 2021 beet campaign in Zeitz, Germany, was the longest in the sugar factory's history at 177 days, while the 2022 campaign was 144 days. Both campaigns faced challenges with beet storage and supply, as well as climatic conditions causing damage to harvested beets. These challenges resulted in a reduction in the purity and pH value of the raw juice, and increased lime salts and turbidity in the thin and thick juice.
Südzucker AG, to which the Zeitz factory belongs, implemented several measures, including technological adjustments, the use of dextranase, increased washing cycles, and filter sleeve changes. The high juice volumes from the campaigns led to year-round sugar production but also required blending lower quality juices with good quality ones. The long production periods resulted in short shutdowns used for maintenance and investment measures.

Incipient Jomon — 14 000—10 000 BP (16 000—11 500 cal. BP) — the first period of the Neolithic on the Japanese Archipelago the content of which includes the significant changes in lithic industry, the origin of pottery-making, the transformation of economic and settlement patterns against the background of climatic and landscape fluctuations in the Final Pleistocene and the Pleistocene-Holocene boundary. The abundance of archaeological materials and an extensive database allow us to evaluate different variants of the internal division of Incipient Jomon, to examine the common and local manifestations of transitional periods for Hokkaido, Honshu, and Kyushu, and to make a correlation of Incipient Jomon lithic industry with the industry of the Initial Neolithic Osipovka culture in the neighboring territory of the Russian Far East.

This study brings results on Normalized Difference Vegetation Index (NDVI), the Adjusted Vegetation Index of Soil (SAVI) and the Index of Water by Normalized Difference (NDWI) through a method that uses correlation matrices built on a pixel to pixel combination for spatial and temporal analysis of plant cover. The study was developed by using Landsat 8 images from January and August, 2015. Image processing was performed with ArcGis and Matlab building correlation matrices to evaluate variations of each index in Brazilian vegetation. Results showed decreasing values of the three indices from wet to dry period. Climatic conditions influenced on the vigor and moisture content of vegetation. The pixel to pixel correlation method is appropriated to study vegetation changes and quantify increase, decrease or maintenance of vegetation.

This paper discusses written historical documentation and paleo- environmental evidence in order to explore connections between climatic and socio-economic change. It focuses thereby on the Byzantine Empire and the eastern Mediterranean more generally in the period between the collapse and "restoration" of Byzantine rule in Constantinople (1204–1261) and the beginning of Ottoman expan-sion in the Balkans in 1352, which roughly coincided with the outbreak of the first wave of the "Black Death" in 1347. The paper entails juxtaposing various older scenar-ios of "fatal" social and political developments in Byzantine history with new studies based on proxy data from regions across the Balkans and Asia Minor and comparing these events with developments in other polities of the region during the transforma-tion from the "Medieval Climate Anomaly" to the "Little Ice Age."

The purpose of this research is to analyze vulnerability and adaptability of agrarian systems face to climate variability and social changes in Basse-Casamance, a region where rice growing is a multi-decade. The study focuses on an important aspect of rural development in a context of armed conflict and raises the issue of the dynamics of these systems, which have become an environmental, socio-cultural, economic and political issue. It emphasizes the relationship between the Diola peasant and his environment, through a remarkably ingenious agricultural management, which structuring reflects the deep appropriation of land and embodies a fundamental socio-spatial dimension of the "identity" of the region. Issued from a long social and societal history, from the ingenuity of techniques associated with the exploitation of the environment and the diversity of agrarian systems, rice growing in Basse-Casamance has been facing for more than forty years, multiple external forces, with decisive environmental and socio-economic consequences. The strong climatic variability (rainfall in particular), a key aspect in tropical environment, seems to be one of the triggers of the past and current environmental transformations observed in the region. It has led to other extreme events, with complex contours (high salinity of water and soil, soil acidity, siltation, etc.), therefore, rice growing in many plots of the region has become unpracticable. The magnitude of the changes is measured by a global and multi-scale approach in geography, which integrates both geomatics' tools (Remote Sensing, GIS, statements of GPS points) and fieldwork (water and soil sampling, physico-chemical analyzes, direct observations, household surveys and people perceptions). This approach led to an important mapping of the observations from diachronic levels and revealed the major trends of the mutations over whole Basse-Casamance and on the scale of rice growing areas. The historical approach has led to a better understanding of the basis of this rice-growing and the conditions under which it is developing. This paradigm is greatly influenced by the public policies in terms of rice growing, implemented in Basse-Casamance, with a view of improving the livelihoods of the rural people. In many cases, however, they have proved to be ineffective and inefficient. ; Ce travail de recherche a pour objet l'analyse de la vulnérabilité et de l'adaptabilité des systèmes agraires face à la variabilité climatique et aux changements sociaux en Basse-Casamance, région où la riziculture est multiséculaire. L'étude s'intéresse à un aspect important du développement rural dans un contexte de conflit armé et pose la problématique de la dynamique de ces systèmes, devenue un enjeu environnemental, socio-culturel, économique et politique. Elle met ainsi l'accent sur les rapports entre le paysan diola et son environnement, au travers des aménagements agricoles d'une ingéniosité remarquable et dont la structuration traduit la profonde appropriation de l'espace et incarne une dimension socio-spatiale fondamentale de l'identité de la région. Produit d'une longue histoire sociale et sociétale, de l'ingéniosité des techniques associées à l'exploitation du milieu et de la diversité des systèmes agraires, la riziculture de Basse-Casamance fait face, depuis plus d'une quarantaine d'années, à de multiples forces externes, aux conséquences environnementales et socioéconomiques décisives. La forte variabilité climatique (pluviométrique notamment), aspect important en milieu tropical, semble être un des éléments déclencheurs des transformations environnementales passées et actuelles observées dans la région. Elle a entraîné d'autres évènements extrêmes aux contours complexes (salinité élevée des eaux et des sols, acidité des sols, ensablement, etc.), rendant ainsi inaptes la riziculture dans de nombreuses parcelles de la région. L'ampleur des modifications est mesurée grâce à une approche géographique globale et multiscalaire, qui intègre à la fois les outils de la géomatique (Télédétection, SIG, Relevés de points GPS) et les travaux de terrain (prélèvements d'échantillons d'eaux et de sols, analyses physico-chimiques, observations directes, enquêtes-ménages et perceptions de la population). Cette approche a conduit à une importante cartographie des faits observés à partir de niveaux diachroniques et a révélé les grandes tendances des mutations sur l'ensemble de la Basse-Casamance et à l'échelle des terroirs rizicoles. L'approche historique a permis de mieux comprendre les fondements de cette riziculture et les conditions de son évolution actuelle. Ce paradigme est grandement influencé par les politiques publiques d'aménagement rizicole mises en œuvre en Basse-Casamance, dans un souci d'amélioration des conditions de vie de la population rurale. Celles-ci se sont, néanmoins, révélées, dans nombre de cas, inefficaces et inefficientes.

The purpose of this research is to analyze vulnerability and adaptability of agrarian systems face to climate variability and social changes in Basse-Casamance, a region where rice growing is a multi-decade. The study focuses on an important aspect of rural development in a context of armed conflict and raises the issue of the dynamics of these systems, which have become an environmental, socio-cultural, economic and political issue. It emphasizes the relationship between the Diola peasant and his environment, through a remarkably ingenious agricultural management, which structuring reflects the deep appropriation of land and embodies a fundamental socio-spatial dimension of the "identity" of the region. Issued from a long social and societal history, from the ingenuity of techniques associated with the exploitation of the environment and the diversity of agrarian systems, rice growing in Basse-Casamance has been facing for more than forty years, multiple external forces, with decisive environmental and socio-economic consequences. The strong climatic variability (rainfall in particular), a key aspect in tropical environment, seems to be one of the triggers of the past and current environmental transformations observed in the region. It has led to other extreme events, with complex contours (high salinity of water and soil, soil acidity, siltation, etc.), therefore, rice growing in many plots of the region has become unpracticable. The magnitude of the changes is measured by a global and multi-scale approach in geography, which integrates both geomatics' tools (Remote Sensing, GIS, statements of GPS points) and fieldwork (water and soil sampling, physico-chemical analyzes, direct observations, household surveys and people perceptions). This approach led to an important mapping of the observations from diachronic levels and revealed the major trends of the mutations over whole Basse-Casamance and on the scale of rice growing areas. The historical approach has led to a better understanding of the basis of this rice-growing and the conditions under which it is developing. This paradigm is greatly influenced by the public policies in terms of rice growing, implemented in Basse-Casamance, with a view of improving the livelihoods of the rural people. In many cases, however, they have proved to be ineffective and inefficient. ; Ce travail de recherche a pour objet l'analyse de la vulnérabilité et de l'adaptabilité des systèmes agraires face à la variabilité climatique et aux changements sociaux en Basse-Casamance, région où la riziculture est multiséculaire. L'étude s'intéresse à un aspect important du développement rural dans un contexte de conflit armé et pose la problématique de la dynamique de ces systèmes, devenue un enjeu environnemental, socio-culturel, économique et politique. Elle met ainsi l'accent sur les rapports entre le paysan diola et son environnement, au travers des aménagements agricoles d'une ingéniosité remarquable et dont la structuration traduit la profonde appropriation de l'espace et incarne une dimension socio-spatiale fondamentale de l'identité de la région. Produit d'une longue histoire sociale et sociétale, de l'ingéniosité des techniques associées à l'exploitation du milieu et de la diversité des systèmes agraires, la riziculture de Basse-Casamance fait face, depuis plus d'une quarantaine d'années, à de multiples forces externes, aux conséquences environnementales et socioéconomiques décisives. La forte variabilité climatique (pluviométrique notamment), aspect important en milieu tropical, semble être un des éléments déclencheurs des transformations environnementales passées et actuelles observées dans la région. Elle a entraîné d'autres évènements extrêmes aux contours complexes (salinité élevée des eaux et des sols, acidité des sols, ensablement, etc.), rendant ainsi inaptes la riziculture dans de nombreuses parcelles de la région. L'ampleur des modifications est mesurée grâce à une approche géographique globale et multiscalaire, qui intègre à la fois les outils de la géomatique (Télédétection, SIG, Relevés de points GPS) et les travaux de terrain (prélèvements d'échantillons d'eaux et de sols, analyses physico-chimiques, observations directes, enquêtes-ménages et perceptions de la population). Cette approche a conduit à une importante cartographie des faits observés à partir de niveaux diachroniques et a révélé les grandes tendances des mutations sur l'ensemble de la Basse-Casamance et à l'échelle des terroirs rizicoles. L'approche historique a permis de mieux comprendre les fondements de cette riziculture et les conditions de son évolution actuelle. Ce paradigme est grandement influencé par les politiques publiques d'aménagement rizicole mises en œuvre en Basse-Casamance, dans un souci d'amélioration des conditions de vie de la population rurale. Celles-ci se sont, néanmoins, révélées, dans nombre de cas, inefficaces et inefficientes.

The purpose of this research is to analyze vulnerability and adaptability of agrarian systems face to climate variability and social changes in Basse-Casamance, a region where rice growing is a multi-decade. The study focuses on an important aspect of rural development in a context of armed conflict and raises the issue of the dynamics of these systems, which have become an environmental, socio-cultural, economic and political issue. It emphasizes the relationship between the Diola peasant and his environment, through a remarkably ingenious agricultural management, which structuring reflects the deep appropriation of land and embodies a fundamental socio-spatial dimension of the "identity" of the region. Issued from a long social and societal history, from the ingenuity of techniques associated with the exploitation of the environment and the diversity of agrarian systems, rice growing in Basse-Casamance has been facing for more than forty years, multiple external forces, with decisive environmental and socio-economic consequences. The strong climatic variability (rainfall in particular), a key aspect in tropical environment, seems to be one of the triggers of the past and current environmental transformations observed in the region. It has led to other extreme events, with complex contours (high salinity of water and soil, soil acidity, siltation, etc.), therefore, rice growing in many plots of the region has become unpracticable. The magnitude of the changes is measured by a global and multi-scale approach in geography, which integrates both geomatics' tools (Remote Sensing, GIS, statements of GPS points) and fieldwork (water and soil sampling, physico-chemical analyzes, direct observations, household surveys and people perceptions). This approach led to an important mapping of the observations from diachronic levels and revealed the major trends of the mutations over whole Basse-Casamance and on the scale of rice growing areas. The historical approach has led to a better understanding of the basis of this rice-growing and the conditions under which it is developing. This paradigm is greatly influenced by the public policies in terms of rice growing, implemented in Basse-Casamance, with a view of improving the livelihoods of the rural people. In many cases, however, they have proved to be ineffective and inefficient. ; Ce travail de recherche a pour objet l'analyse de la vulnérabilité et de l'adaptabilité des systèmes agraires face à la variabilité climatique et aux changements sociaux en Basse-Casamance, région où la riziculture est multiséculaire. L'étude s'intéresse à un aspect important du développement rural dans un contexte de conflit armé et pose la problématique de la dynamique de ces systèmes, devenue un enjeu environnemental, socio-culturel, économique et politique. Elle met ainsi l'accent sur les rapports entre le paysan diola et son environnement, au travers des aménagements agricoles d'une ingéniosité remarquable et dont la structuration traduit la profonde appropriation de l'espace et incarne une dimension socio-spatiale fondamentale de l'identité de la région. Produit d'une longue histoire sociale et sociétale, de l'ingéniosité des techniques associées à l'exploitation du milieu et de la diversité des systèmes agraires, la riziculture de Basse-Casamance fait face, depuis plus d'une quarantaine d'années, à de multiples forces externes, aux conséquences environnementales et socioéconomiques décisives. La forte variabilité climatique (pluviométrique notamment), aspect important en milieu tropical, semble être un des éléments déclencheurs des transformations environnementales passées et actuelles observées dans la région. Elle a entraîné d'autres évènements extrêmes aux contours complexes (salinité élevée des eaux et des sols, acidité des sols, ensablement, etc.), rendant ainsi inaptes la riziculture dans de nombreuses parcelles de la région. L'ampleur des modifications est mesurée grâce à une approche géographique globale et multiscalaire, qui intègre à la fois les outils de la géomatique (Télédétection, SIG, Relevés de points GPS) et les travaux de terrain (prélèvements d'échantillons d'eaux et de sols, analyses physico-chimiques, observations directes, enquêtes-ménages et perceptions de la population). Cette approche a conduit à une importante cartographie des faits observés à partir de niveaux diachroniques et a révélé les grandes tendances des mutations sur l'ensemble de la Basse-Casamance et à l'échelle des terroirs rizicoles. L'approche historique a permis de mieux comprendre les fondements de cette riziculture et les conditions de son évolution actuelle. Ce paradigme est grandement influencé par les politiques publiques d'aménagement rizicole mises en œuvre en Basse-Casamance, dans un souci d'amélioration des conditions de vie de la population rurale. Celles-ci se sont, néanmoins, révélées, dans nombre de cas, inefficaces et inefficientes.