Tesemash Abebe
In recent decades, climate change has become a major environmental and socioeconomic challenge in Ethiopia. The study used the statistically downscaled daily data in 30-year intervals from the second generation of the Earth System Model (CanESM2) under three Representative Concentration Pathways (RCPs): RCP2.6, 4.5, and 8.5 for three future time slices; near-term (2010-2039), midcentury (2040-2069), and end-century (2071-2099). The observed maximum and minimum temperature and precipitation values are a good simulation of the modeled data during the calibration and validation periods using the Pearson coefficient (R), the correlation coefficient (R2), and the Nash-Sutcliffe efficiency (NSE). In three sampled stations (Awash Arba, Shewa Robt, and Erer), there is a minor difference between all considered scenarios during the 2020s. The results of maximum and minimum temperature are expected to increase by 0.03°C–0.09°C and 0.05°C–0.2°C, respectively, during the 2020s. While the middle and far-future period’s exhibit larger variations in the degrees of warming. The maximum and minimum temperature in the middle-future period (2050s) is likely expected to increase by 0.2°C–0.8°C and 0.2°C–1.93°C, respectively. During the 2080s, the worst-case scenarios (RCP8.5) are the ones with the greatest expected increase in maximum and minimum temperature of 1.03°C–1.6°C and 1°C–3.9°C, respectively, which are significantly higher than the remaining scenarios, varying approximately from 0.18°C–0.7°C and 0.13°C–1.6°C, respectively. In all the scenarios, the projected mean annual maximum and minimum temperature in the 2080s are the highest. The increment in minimum temperature is higher than the maximum temperature in almost all time slices under the three RCP scenarios. The mean annual precipitation is predicted to increase significantly at most stations over the three sampled stations in the middle Awash River basin. In the mid-future period (2050s), the mean annual precipitation will increase by 4.3%–16.4%. During the far-future period (2080s), the average annual precipitation is likely expected to increase by 3.4%–40.5% compared to the reference period. Temperature and precipitation are projected to increase in total amounts under alltime slices and emissions pathways. In all emission scenarios, the greatest changes in maximum temperature, minimum temperature, and precipitation are predicted by the end of the century. This implies that climate-smart actions in development policies and activities need to consider locally downscaling expected climatic changes.