Climate change projections in the Awash River Basin of Ethiopia using Global and Regional Climate Models

Abstract

Understanding the long‐term variability and change in climate variables is critical for the sustainable management of water resources. This research aimed to project and analyse climate change in the Awash River Basin (ARB) using bias‐corrected Global and Regional Climate Model simulations. The analysis included a baseline period from 1986 to 2005 and two future scenarios (2050s and 2070s) under two representative concentration pathways (RCP4.5 and RCP8.5). Following the evaluation of bias correction methods, the distribution mapping and power transformation were used for temperature and precipitation projection, respectively. The 2050s and 2070s RCP4 simulations showed an increase in precipitation during half of the months with 32 and 10%, respectively. Moreover, the 2050s and 2070s RCP8.5 simulation indicated a decrease in precipitation with 18 and 26%, respectively. The 2050s and 2070s RCP8.5 simulation indicated a significant decrease in precipitation in four of the months (February/March to May) with the highest decreasing rate of 34.7%. The 2050s and 2070s RCP4.5 simulation showed an increase of 0.48–2.6°C in maximum temperature. In the case of RCP8.5, the simulated maximum temperature increase reached 3.4 and 4.1°C in the 2050s and 2070s, respectively. The future precipitation and temperature change projected in ARB might worsen the water stress and incidence of dry spells in the basin, and hence mitigation strategies and management options to reduce this negative impact should be developed.