The future climate of the African continent

Abstract

The software used in this study is MAGICC/SCENGEN version 5.3, which is consistent with the IPCC Fourth Assessment Report, Working Group I. MAGICC was used to produce projections of the concentrations of key greenhouse gases, namely C02, CH4 and N20, and to generate projections of future global-mean temperature and sea level rise between 1990 and 2100. Applying the model HadCM3, results for the global-mean temperature were then used to drive SCENGEN. Employing a pattern scaling method, SCENGEN was used to present a climatic picture of the African continent. The climatic variables under study were temperature, precipitation and their associated variability, while the adopted emission scenarios were AlFIMI and WRE650. The African continent was divided into three sub-regions, specifically East Africa, West Africa and South Africa, which includes the island of Madagascar. For each subregion, output results were obtained on a seasonal and annual basis for the years 2020, 2040, 2060, 2080 and 2100. When employing a climate sensitivity of 3.0°C, the range of the globalmean temperature increase for the year 2100 with respect to 1990 is from 1.7 to 5.0°C and the corresponding projections in the global-mean sea level rise is between 24 and 53 cm. It is shown that there is a direct relationship between the global-mean temperature increase and the atmospheric concentration of C02. Other results suggest that in general, climate has inertia and the global-mean sea level will continue to rise even after the emissions and concentrations of C02 are stabilized. The average annual temperature increase over all sub-regions is 6.0°C when employing the model HadCM3 with the scenario AlFI-Ml, and 3.0°C with the scenario WRE650. Furthermore, variability analysis suggests a significant increase in the number of extremely warm days, linked with a drop in extremely cold days. The average annual precipitation is also projected to increase. However, in certain susceptible regions the risk of droughts will increase and the wet climate of the tropical regions is likely to intensify.