CMIP6-based analysis of precipitation and temperature trends and their implications on water resource management in the Gidabo Watershed, Ethiopia

ABSTRACT Climate change increasingly threatens water resources, particularly in climate-sensitive regions such as Ethiopia's Gidabo watershed. This study analyzed historical (1995–2014) and future (2021–2040 and 2041–2060) climate trends using an ensemble of six bias-corrected CMIP6 global climate models under SSP2-4.5 and SSP5-8.5 scenarios. The non-parametric Mann–Kendall test and Sen's slope estimator were applied to detect trends in precipitation and temperature. The results show that precipitation exhibits slightly increasing but statistically non-significant trends, with mean rainfall projected to decline by up to 18.2% during the wet season, indicating greater variability and a shift toward drier conditions. Conversely, both maximum and minimum temperatures show significant upward trends across all seasons and scenarios. The mean annual minimum temperature is projected to increase from 12.01 °C in the baseline to 15.63 °C by mid-century under SSP5-8.5, a rise of +3.62 °C (≈30%). These changes suggest hotter, more evaporative, and water-stressed conditions that could intensify agricultural droughts and ecosystem stress. The findings highlight the need to integrate CMIP6-based projections into climate-resilient water allocation, irrigation planning, and watershed management to ensure sustainable resource use in the Gidabo watershed and similar East African regions.