Avaliação do impacto nos extremos climáticos de precipitação na África subsaariana devido ao aumento da concentração dos gases do efeito estufa

Abstract

Sub-Saharan Africa has experienced significant warming in recent decades, which has intensified extreme climate events. Its vulnerability is primarily due to the region’s dependence on subsistence agriculture and its low adaptive capacity. Regions such as the Horn of Africa and the Sahel face prolonged droughts, while Central Africa, particularly the Congo rainforest area, experiences more intense and irregular rainfall. In the south, countries like Mozambique and Zimbabwe are frequently affected by cyclones and recurrent flooding. This study aims to answer the following question: How does the increase in greenhouse gas concentrations affect the frequency and intensity of extreme climate events in Sub-Saharan Africa? To address this, historical data (1981–2010) and future projections (2071–2100) were analyzed, based on CMIP6 scenarios SSP2-4.5 and SSP5-8.5. Climate models HadGEM3-LL, MIROC6, and NorESM2-MM were used, and validated against CPC data through BIAS, RMSE, and Taylor Diagram calculations. The climate indices analyzed include CDD, CWD, RX1Day, RX5Day, and R95P, complemented by a sensitivity analysis to identify anomalies and statistical significance. The results confirm trends observed in previous studies, with projected prolonged droughts in the north (Sahel) and south (Namibia and Botswana), and an increase in extreme precipitation over Central Africa (Congo rainforest area) under both scenarios. However, the effects are more pronounced under the SSP5 scenario, with projections of 160 to 200 CDD days and 30 to 50 CWD days in northern and southern Sub-Saharan Africa, and a significant increase in extreme rainfall: RX1Day and RX5Day exceeding 150 mm in Central and Southeastern regions, and R95P surpassing 400 mm in Central Africa indicating a rise in both frequency and intensity of storms, and highlighting the urgent need for adaptation measures. Keywords: Sub-Saharan Africa, Climate Change, Climate Extremes, Precipitation, CMIP6, Greenhouse Gases, SSP2 and SSP5 Scenarios.