Recent GIS based national assessments of climate change consequences in France: methods, results and lessons learnt.

Abstract : This paper reviews two recent assessments undertaken in France for evaluating national scale consequences of global change for coastal hazards and risks, namely marine submersion and coastal erosion. In a first approach, the potential consequences of climate change were evaluated in a direct quantitative way, however with high uncertainties in the final evaluation. Recognizing that uncertainties could hardly be reduced, a second assessment based on a multi-criteria evaluation was then undertaken. Geomorphological and marine factors that account for physical vulnerability to coastal hazards were evaluated for 21 coastal entities in metropolitan France. The evaluation was structured using the analytical hierarchy process (AHP). The results highlighted the fact that in some specific regions such as Languedoc-Roussillon (Mediterranean coast) and Pertuis (Atlantic coast), the population is expected to increase more than the mean average, while the coastal zone are also likely to be more strongly affected by coastal hazards. While such national scale evaluations in highly diversified coastal environments are still arguable, they may help identifying unsustainability in current trends and help defining priorities for future adaptation strategies.