Southern African Climate Change: Processes, Models, and Projections

Southern Africa, along with the Mediterranean and eastern South America, is one of three major land regions projected to dry in the future. Confidence in the drying trend relies on a clear understanding of the regional climate and evaluation of the climate models used for projections. This paper reviews our understanding of southern African climate and evaluates the performance of successive climate model generations. A key finding is improved confidence in projections of early summer drying. The drying results from a delayed seasonal cycle, with regional features such as the Congo Air Boundary and heat lows increasing in frequency in the future. Future drying is matched by emerging observed trends indicating large temperature increases and drying in early summer, in addition to projections of increases in extreme rainfall, heatwaves, and dry spells. There is greater uncertainty in climate changes in the core rainy season (December to February), in part due to systematic climate model biases in this season, which have worsened through model generations. Model biases are compounded by a lack of in situ observations of key regional climate features, including heat lows, tropical lows, and mesoscale convective systems. The review recommends a focus on quantifying changes in circulation features and rainfall systems, which are well known but lack comprehensive assessment of trends and future projections. The future of tropical cyclone risk is a priority, especially given the increase in the frequency of intense tropical cyclones in the Mozambique Channel over the last 40 years.This article is categorized under: Paleoclimates and Current Trends > Modern Climate Change