Response of the European forests to extreme climatic events predicted for the 21st century: sensitivity to climate models and their variability

Significant climatic changes are currently observed and, according to projections, will be strengthened over the 21st century throughout the world with the enhanced greenhouse effect. Climate will be generally warmer with notably changes in the seasonality and in the precipitation regime. The CARAIB dynamic vegetation model is used to evaluate and analyse the potential impacts of climate change on forests ecosystems in Europe. Changes in the hydrological budget as well as in the intensity and the frequency of wildfires and their effects on forest productivity and distribution are especially assessed. CARAIB is driven by the ARPEGE-Climat model and some other regional climate models from the European Union (EU) project ENSEMBLES forced with IPCC A1B emission scenario. Climate projections indicate changes in variability and frequency of extreme events. Since climate variability governs the response of plant species (e.g. net primary productivity, NPP) to climate change, we analyse the climate variability (seasonal and interannual) given by climate models comparing it with the observed climate variability (CRU TS 3.0 historical climate dataset) over the period 1961-1990. The variability modelled by the ARPEGE-Climat model is notably slightly more pronounced than the observed one, at least for some areas. Since discrepancies between modelled and observed current climate variability may affect NPP variability calculated for the future as well as the intensity and the frequency of severe drought period and wildfires, comparing the forest ecosystem evolutions obtained with a range of climate models allows improving the assessment of climate change impacts on forest in the future.