Impacts of Climate Change on Temperature and Rainfall on Dawa Sub-watershed, Genale Dawa River Basin, Southern Ethiopia

Abstract

Understanding how climate change affects the frequency and length of temperature and rainfall is global issue. Climate change is statistical variations over an extended period in the features of the climate system, such as variations in global temperatures and precipitation, caused by human and natural sources. In this work coordinated regional climate downscaling experiment for Africa, which integrates climate forecasts from Coupled Model Intercomparison Project5 based on an ensemble of GCM RCM model was used to statistically downscale the climate change scenarios. This study aimed to estimate climate change impacts on temperature and rainfall. The impact of climate change has been evaluated by reporting under RCP4.5 and 8.5 scenarios. For the extraction and bias correction of the daily maximum and minimum temperature, as well as rainfall of 30-year overlap periods, CMhyd has been employed. The annual minimum temperatures are predicted to increase by 2.94, 3.45, 3.21, and 3.59°C and annual maximum temperatures increased by 2.61, 2.83, 2.71 and 3.36°C for RCP4.5 and RCP8.5 respectively. The change in rainfall reveals annual average decreases of 8.45 to 9.3% and 10.5 to 10.95% at RCP4.5 and 8.5, respectively. Considering the evaluated parameters, minimum and maximum temperatures increased trends but for the rainfall, large fluctuations were predicted. Moreover, in the study years for the parameters in all simulated models, the RCP8.5 scenario estimated a higher amount than the RCP4.5 scenario. Implement various trees, apply water harvesting structure, Surface runoff harvesting and more multiple GCM-RCM driving models with various RCM outputs to improve more prediction accuracy in the future studies.