Evident decrease in future European soil moisture in the Kiel Climate Model

During the last few decades, the European climate has changed significantly. Extreme temperatures are now more frequent than ever since the start of industrialization and changes in the water cycle evident. The soil water content could be affected by these changes disturbing the daily life of many people. More often than we would like, anthropogenic factors and more specifically the CO2 emissions are found to be the causes of these perturbations. In this study, we look into the European soil moisture trends in a changing climate. To achieve this, we use a single grand ensemble of 100 members performed with the Kiel Climate Model (KCM). Each simulation starts with different initial conditions taken from a pre-industrial control run and is forced by a 1%-CO2 increase per year. This means that the atmospheric CO2-concentration doubles after 70 years and quadruples after 140 years. Strong drying over most of Europe is simulated with more than 95% of the ensemble members agreeing on the sign of the change. Central Europe experiences a particularly large drying during spring and summer, while the Mediterranean region is affected all year long by drying. The northern European soil moisture also decreases, but to a lesser extent. The changes over all of Europe are mainly due to a reduction in precipitation and, to a certain degree, an increase in evaporation. Precipitation trends in the KCM ensemble are in good agreement with that in the CMIP6 models forced by the shared socioeconomic pathway 5-8.5 (SSP585).