Sécheresses des sols en France et changement climatique : Résultats et applications du projet ClimSec

Abstract

The ClimSec project has studied the impact of climate change on drought and soil water over France by using a climatological reanalysis of the SAFRAN/ISBA/MODCOU suite (SIM) since 1958. Standardized drought indices for precipitation (SPI) and soil moisture (SSWI) have been defined for research purposes to characterize the various kinds of events. They were then adapted for operational hydrological monitoring and used to assess the exceptional drought of spring 2011. These indices were also calculated for future climate from the various regionalized climate projections available over France. Three particular experiments in socio-economic scenarios, climate models and downscaling methods have been run to estimate the relative importance of the different uncertainties in drought evolution. The assessment of 21st century drought evolution shows a much earlier and more intense occurrence of changes for agricultural droughts linked to soil moisture deficits than for meteorological drought linked with precipitation deficits. Climate projections suggest that France could be affected on the second half of the 21st century by a quasi-continuous drought with a strong intensity, totally unknown in present climate.