Projection of climate change impact on the occurrence of drought events in Poland

In the era of human-induced climate change, droughts are one of the extreme events that can severely impact water resources, regional agriculture and the ecological environment. A reliable projection of droughts for the future is crucial with the rapid global increase in the frequency and intensity of droughts. This research aims to project the future of droughts in Poland by the end of the 21st century. To achieve this, we use a multi-model mean ensemble of 26 downscaled and bias-corrected high-resolution general circulation models (GCMs) under Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) scenarios from Coupled Model Intercomparison Project Phase 6 (CMIP6) to project changes in temperature and precipitation. Then, estimation of droughts was completed for the periods 2031-2060 and 2071-2100 according to the Standardized Precipitation Evapotranspiration Index (SPEI) at three-time scales of 1, 6 and 12 months to address three types of droughts (i.e., meteorological, agricultural and hydrological, respectively). The temperature and precipitation projection revealed that temperature will increase in both future periods, which is dramatic under the SSP3-7.0 and SSP5-8.5 scenarios. However, precipitation fluctuates based on scenarios with a slight increase, excluding far-future periods under SSP3-7.0, and SSP5-8.5 scenarios. The projected changes in droughts based on SPEI under SSP scenarios showed a decrease in frequency in the near-future, but an increase under SSP2-4.5, SSP3-7.0 and SSP5-8.5 in the far-future. The number of severe and moderate droughts is expected to rise, with a notable increase in agricultural and hydrological droughts (SPEI-6 and SPEI-12) under SSP3-7.0 and SSP5-8.5.