Evaluation of Past and Future Climate Trends under CMIP6 Scenarios for the UBNB (Abay), Ethiopia

Climate predictions using recent and high-resolution climate models are becoming important for effective decision-making designing appropriate change adaptation mitigation strategies. Due to highly variable data scarcity of the upper Blue Nile Basin, previous studies did not detect specific unified trends. This study discusses, past future projections under CMIP6-SSPs scenarios basin. For models’ validation selection, reanalysis were used after comparing with area-averaged ground observational data. Quantile mapping systematic bias correction Mann–Kendall trend test applied evaluate trends selected CMIP6 during 21st century. Results revealed that, ERA5 temperature GPCC precipitation have best agreement basin data, MRI-ESM2-0 BCC-CSM-2MR based on their highest performance. The mean annual maximum near (long)-term period shows an increase 1.1 (1.5) °C, 1.3 (2.2) 1.2 (2.8) 1.5 (3.8) °C four SSPs. On other hand, show slightly (statistically insignificant) increasing periods by 5.9 (6.1)%, 12.8 (13.7)%, 9.5 (9.1)%, 17.1(17.7)% SSPs scenarios.