Assessment of drought conditions under climate change scenarios in Central Europe (Poland) using the standardized precipitation index (SPI)

Human-induced climate change led to a rise in the occurrence and severity of extreme events, including droughts, on a global scale. The assessment of drought conditions is important in understanding and mitigating drought risk in the future. This study used 26 General Circulation Models (GCMs) of high-resolution NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) Coupled Model Intercomparison Project Phase 6 (CMIP6) datasets and the standardized precipitation index (SPI) to assess the future of droughts in Central Europe (Poland) under four Shared Socioeconomic Pathways (SSPs) scenarios (i.e., SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5). For this purpose, precipitation in the near future (NF) (2031-2060) and far future (FF) (2071-2100) periods were projected, and then an assessment of droughts at time scales of SPI-01, SPI-06 and SPI-012 was carried out. The projection of spatial variability of precipitation in Poland revealed that it will increase slightly (10-30%) under SSP1-2.6 and SSP2-4.5 scenarios, while in the FF, it is projected to increase by 20-50% under SSP3-7.0 and SSP5-8.5 scenarios in the north/central and south of Poland, respectively. Assessment of the future of droughts demonstrated that in the NF, the frequency of droughts will decrease by approximately 20-60% in all SPI timescales (SPI-01, SPI-06, SPI-12) under all SSP scenarios. In the FF, drought frequency will increase significantly, particularly under SSP3-7.0 and SSP5-8.5 scenarios, with 50-100% increases for SPI-06 (agricultural drought) and SPI-12 (hydrological drought).