Evaluating the impacts of sea level rise on coastal wetlands in Languedoc-Roussillon, France

Sea-level rise due to climate change creates new risks of submersion in coastal areas that must be taken into account. Although these are long-term risks for 2100, it is important to anticipate possible consequences in order to identify the most vulnerable areas or issues and develop the appropriate adaptation policies. The aim of this paper is to examine the consequences of such sea-level rise for wetlands in the Languedoc-Roussillon region (France) which is particularly at risk of submersion. The analysis is based on the worst case scenario of a one meter sea level rise by 2100, with a variety of adaptive strategies: denial, laissez-faire and strategic retreat of infrastructure and buildings. This latter strategy assumes that the retreat wetlands is unconstrained. The evaluation examines the losses and transformations of ecological habitats, depending on their distance from salt water. Estimating damages and benefits requires first, to study the evolution of the services supplied by different habitats and second, to estimate the value of the economic impact. This approach demonstrates the superiority of a strategic retreat policy which would halve the damages resulting from submersion.</p

Evaluating the impacts of sea level rise on coastal wetlands in Languedoc-Roussillon, France

Sea-level rise due to climate change creates new risks of submersion in coastal areas that must be taken into account. Although these are long-term risks for 2100, it is important to anticipate possible consequences in order to identify the most vulnerable areas or issues and develop the appropriate adaptation policies. The aim of this paper is to examine the consequences of such sea-level rise for wetlands in the Languedoc-Roussillon region (France) which is particularly at risk of submersion. The analysis is based on the worst case scenario of a one meter sea level rise by 2100, with a variety of adaptive strategies: denial, laissez-faire and strategic retreat of infrastructure and buildings. This latter strategy assumes that the retreat wetlands is unconstrained. The evaluation examines the losses and transformations of ecological habitats, depending on their distance from salt water. Estimating damages and benefits requires first, to study the evolution of the services supplied by different habitats and second, to estimate the value of the economic impact. This approach demonstrates the superiority of a strategic retreat policy which would halve the damages resulting from submersion.</p

Levers for the agroecological transition of tropical agriculture

International audienceTo promote greater sustainability in agriculture, development of agroecology is increasingly being invoked. What are the conditions for establishing agroecological production in tropical regions? Based upon case studies in several tropical areas, we provide here some answers to this question. We review the "pillars" (i.e. principles) and the "implementation levers" (i.e., tools) for the development of agroecology. We identify three main pillars: (1) the mobilization and management of ecological processes for the sustainable production and the resilience of agroecosystems; (2) the development of interactions between technical, social, environmental, and institutional components of agroecosystems for a holistic approach to agroecology; and (3) the scaling up of agroecology that takes place with a plurality of actions and pathways at different organization levels rather than an increase in resources and a replication of standardized technical processes. To implement these three pillars, we identify 11 main biotechnical, cognitive, socio-political, and organizational levers. Bio-technical levers include those for (1) mobilizing complementarity between crop species to optimize natural resources use, (2) mobilizing functional biodiversity at the plot scale to optimize natural regulation of pests and diseases, (3) managing biodiversity at landscape and territorial scales, (4) increasing the efficiency of biogeochemical cycles, and (5) renewing targets for genetic improvement. Cognitive, socio-political, and organizational levers include those for (6) political and institutional action at the national and global level, (7) action at the local level to support producers, (8) political and organizational action at the territorial level, (9) the marketing and the development of new agri-chains, (10) the development of new methods for evaluating production systems, and (11) the recognition of the values of gender and generation within families and other organisational levels. This paper provides an overall orientation for the agroecological transition in tropical agriculture and also considers the socio-political context that underlies this transition