Rising heavy precipitation extremes in Central European river basins under a high emission scenario

This study assesses historical trends and future projections of extreme precipitation events in Central Europe's Vistula and Oder (Odra) transboundary river basins using climate indices recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI). Utilizing bias-corrected EURO-CORDEX regional climate models under the high-emission RCP8.5 scenario, we evaluated changes in the frequency, intensity, and contribution of heavy precipitation events from 2006 to 2100 compared to a historical baseline (1990-2019). The findings demonstrate a consistent and statistically significant (based on Mann-Kendall and Sen's slope) increase in extreme precipitation events, notably in heavy rainfall days (R10mm and R20mm), intensity metrics (maximum 1-day and 5-day precipitation, Rx1day and Rx5day), and the proportion of total precipitation contributed by extreme events (R95pTOT and R99pTOT). Spatial analysis reveals that the southern mountainous areas historically experience and will continue to experience the most pronounced changes, though significant increases are projected broadly across the region. Duration indices, such as consecutive dry and wet days (CDD, CWD), showed less clear and more uncertain future trends. The projected intensification of extreme rainfall events has important implications for flood risk management, infrastructure design, and water resource planning in Central Europe. These results underscore the urgent need for proactive adaptation measures to reduce vulnerabilities and enhance resilience against climate-induced precipitation extremes.