Assessment of future changes on hydrometeorological and river flow extremes in the Atrato river basin under CMIP6 scenarios

The Atrato River Basin, a critical hydrological resource in Colombia, is increasingly vulnerable to the dual impacts of extreme precipitation events and water scarcity, driven by climate change. This study aims to evaluate the potential impacts of climate change on hydrometeorological and river hydrological extremes in the basin, focusing on short-duration precipitation, peak river discharges, and low-flow conditions. Using state-of-the-art CMIP6 global climate models (GCMs) and four Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5), daily precipitation and temperature projections are statistically and temporally downscaled. In addition, intensity, duration and frequency for historical and future scenarios were assessed. Hydrological modeling using conceptual models quantifies the impacts of projected changes on river flow extremes. This research highlights the urgent need for adaptive strategies, including infrastructure upgrades and integrated water resource management, to mitigate climate-induced risks in the Atrato River Basin. It underscores the importance of robust uncertainty quantification for effective climate adaptation planning.