Projected climate change signals for selected hotspot regions using regional climate simulations in southern Africa  

Abstract

Based on the IPCC AR6 Report, the southern African climate change signal is projected to have a rapid warming compared to the global signal. A decreasing trend in the observed mean precipitation can already be detected in most of southern Africa and an increasing trend in heavy precipitation in eastern southern Africa. While some areas are experiencing increased rainfall and flood risks, other regions are facing reduced rainfall and more frequent droughts. These changes are projected to intensify in a warmer world, with significant impacts on water security, food security and biodiversity.   In this study, the climate change signal for selected hotspot regions in southern Africa were assessed under the “TIPPing points Explained by Climate Change (TIPPECC)” project embedded in the BMBF-funded SASSCAL 2.0 research program. The temperature and precipitation changes were analyzed from existing high resolution simulations (CORDEX, CORDEX-CORE, CMIP6 Simulations) using 2 regional concentration pathways scenarios (RCP2.6 and RCP8.5) during different time periods over case study regions in Namibia, Zambia, Botswana, and South Africa. Based on the initial results from CORDEX-CORE simulations, the ensemble mean of absolute change of precipitation ranges from about -1 to 1 mm/day for both RCP2.6 and RCP8.5 scenarios in the near future. The ensemble mean of absolute change of mean 2-m temperature ranges from about 0.5 to 1.7 K in RCP2.6 and about 0.8 to 3.2 K in RCP8.5 in the near future. These regional climate change signals can be used as information for adaptation measures and sustainable development strategies to mitigate the impacts and enhance the resilience of communities and ecosystems in southern Africa, which is a region already water-stressed and with low adaptive capacity.