Spatiotemporal climate change projection and trend analysis using selected downscaled CMIP6 models for water action over awash River Basin, Ethiopia

Abstract

Climate change exacerbates existing risks, particularly concerning water security, by altering flow volumes, precipitation patterns, and overall water availability. This study addresses the gaps in existing climate projections for the Awash River Basin, utilizing advanced models (CMIP6) to analyze spatial and temporal variations in climate, acknowledging that simplistic averaging of climatic data fails to depict critical regional differences within the basin. By deploying enhanced climate models that account for socioeconomic variables, this research aims to provide a more comprehensive understanding of future water resource dynamics, essential for informed policymaking and effective adaptation strategies in response to climate change. Comparative analyses of observed meteorological data and downscaled CMIP6 climate model outputs indicate model efficacy in simulating local climatic conditions, with ACCESS-CM2 selected for maximum temperature and MRI-ES for precipitation projections under various emission scenarios. Temperature trend analysis using the Mann-Kendall test aligns with models predicting consistent rises across the basin, demonstrating up to 9 °C differentials between lowland and upland areas. Precipitation projections also exhibit variability, with increasing intensity in certain regions contrasted by declines in others, especially under higher emissions scenarios. Temperature observations indicate a mean annual range of 10 °C to 30 °C, with projected increases of 1.5–2.0 °C anticipated by the mid-21st century. Notably, historical trends exhibit rising temperatures and altered precipitation patterns, implications of climate change that threaten agriculture, water resources, and biodiversity. These findings underscore the urgency for adaptive water resource management and agricultural strategies in response to the anticipated climatic shifts affecting the Awash River Basin.