Compound dry–hot seasons in Europe – climate change scenarios and uncertainties

Compound effects of drought and heat are regarded as one of the largest hazards in relation to climate change. Characteristics of dry–hot seasons in Europe are studied in an ensemble of CORDEX regional climate models (RCMs). Evaluation against the E–OBS gridded dataset for 1976–2005 shows that the RCMs are able to reproduce the spatial pattern of the dry–hot season length but the seasons tend to start later and interannual variability of their length is often underestimated. Changes in the median length of dry–hot seasons (compared to the 1976–2005 simulated climate) are analysed for three future time slices (2006–2035, 2036–2065, and 2066–2095) and low and high greenhouse gas concentration pathways. Preliminary results show distinct prolongations of dry–hot seasons for 2036–2065 in the Mediterranean and Western Europe (+10–30 days), regardless the concentration pathway. The lengths of dry–hot seasons are projected to be similar in the 2036–2065 and 2066–2095 time slices under the low concentration pathway but the RCMs simulate major prolongations of dry–hot seasons in the high concentration scenario over large parts of Europe (+20–50 days), indicating substantial changes in future European hydroclimate.