Climate Projection in the Volta Basin by 2099: Precipitation and Temperature

Abstract

Climate change is a global phenomenon caused by the emission of greenhouse gases into the atmosphere, resulting in an increase in global average temperatures. It occurs over long periods of time (typically decades). Given the high intrinsic variability of the climate in West Africa, which occurs over short time scales, it is difficult to clearly determine the impacts of general climate change from natural climate variability. The objective of this study is to assess climate change by 2099 in the Volta Basin region during the rainy season from June to September using the ICTP's RegCM4 regional model. This regional model is forced at its boundaries by two CMIP5-ESM global models, GFDL-ESM-2M and HadGEM2-ES, following the latest IPCC RCP4.5 and RCP8.5 scenarios. The results confirm that RegCM4 provides improvements over global models. The projection for 2099 shows that temperatures are higher in the north, with 3 to 4°C under RCP4.5 and 4 to 5°C under RCP8.5. This area also sees a significant decrease in precipitation. In contrast, south of the Volta Basin, there is a significant increase in precipitation. The Sahel remains less rainy and warmer than the Sudano-Sahelian and Guinean regions. In view of these results, environmental issues are very critical for the future. Consequently, there is a need to strengthen the adaptive capacities of farmers and local actors to avoid suffering from so-called natural disasters.