Characterizing Future Trends of Temperature and Rainfall Using CMIP6 Climate Scenarios over Upper Wabe-Sheble River Basin, Ethiopia

Climate change poses significant challenges on agriculture water resources and energy sectors mainly induced by human activities. Climate models’ scenarios play vital role in assessing future temperature and rainfall their impacts on various sectors. This study aims to assessed future rainfall and temperature trend Using CMIP6 under the SSP2-4.5and SSP5-8.5 scenarios over Wabe- Sheble river basin. Data Eight GCMs under were obtained from ESGF, whereas observed data from Ethiopia meteorology institute. An Ensemble model was Best performed for precipitation (RMSE=4.6, NSE=0, r=0.9) and maximum temperature (best performed for minimum temperature relative to individual models. Linear scaling bias correction method was applied to reduced model errors and improve repetitiveness for local climate features. During the near-term period (2031–2060), future rainfall is projected to increase by 17.0%, 7.4%, and 12.9% under SSP2-4.5, while by 22.7%, 15.3%, and 17.4% increases under SSP5-8.5 scenarios during Belg, Kermit, and annual respectively). During the far term (2061-2090) mean maximum temperature (℃) is projected to increase under the SSP2-4.5 by 1.2℃, 1.6℃, 1.8℃, 1.6 whereas, under increase by 3.2℃, 3.7℃, 3.9℃ and 3.8 Bega, Belg Kermit and annual periods respective. Under the SSP2-4.5 scenario future mean minimum temperature (℃) is projected increases /relative by 2.1℃, 2.2 ℃, 3.1℃ and 3.2 during near-term (2031-2060, whereas during the far term (2061-2090) increase 3.0℃, 2.5℃, 3.1℃ and 3.1℃ Bega, Belg Kermit and annual period. Over all, this finding reveals both temperature and precipitation is projected to increases under the SSP2-4.5 and SSP5-8.5 scenarios. Although, future rainfall is projected to increase temperature also increase simultaneously therefor future warming expected to affects agriculture, water resource, range land ecosystems, therefore timely climate information and interventions activities are recommended. Further studies are suggested considers drought and flood assessment and their potential changes under future climate scenarios over the study area.