Climate change impacts and adaptation in Europe, focusing on extremes and adaptation until the 2030s : PESETA III : Task 9, Droughts : final sector report

This document reports the results of the analyses performed within the framework of the PESETA3 project regarding the Task 9 - Droughts. The main objective of this task is to provide robust scientific-based information to stakeholders and decision makers on the possible impacts of future climate scenarios on the occurrence of drought events. This report is focused on the analysis of the variations of soil moisture on the European continent, as well as of a soil moisture-based drought severity indicator (DSI), in order to evaluate the possible increase/decrease in future occurrence and severity of soil drought events and the related hazard and risk. Following the guideline of the project, five bias-corrected climatological datasets were used to force the LISFLOOD hydrological model that produces the daily soil moisture maps used in this analysis. These datasets were part of the EURO-CORDEX package and were used to characterize both the present reference period (1981-2010) and the future scenario at the date when a global 2 °C warming will occur according to the RCP8.5 scenario (different for each dataset and around the mid of the century). In the framework of this project, considering the specific purpose of the report, only the RCP8.5 scenario was selected in order to provide a clear indication on the possible future impacts of a strong climate change. The most relevant findings of the analysis depicted a scenario with differences that are statistically significant only on a limited fraction of the continental territories, with negative impacts limited to the Mediterranean and South-western Europe area for both soil moisture (reduction in water availability during both the dry and the wet season) and extreme drought events (increase in drought hazard). Particularly concerning is the increase of drought hazard over areas that are already drought prone and characterized by semi-arid climate, even if a limited impact on drought risk is expected due to the low present exposure and vulnerability of the same regions. Overall, it appears clear from this study that the EU goal to limit the global warming at 2 °C, as compared to the average temperature in pre-industrial times, will confine the variations in drought impacts to a minor fraction of the European continent in the nearfuture, as shown by the obtained results.