Anthropogenic warming is accelerating recent heatwaves in Africa

Abstract

Climate change is intensifying extreme events worldwide, with Africa emerging as a uniquely vulnerable hotspot where heatwaves increasingly threaten populations and ecosystems. This study quantifies the roles of anthropogenic aerosols, greenhouse gases, and internal variability in trends of daytime, nighttime, and compound heatwaves. Using the Community Earth System Model 2—Large Ensemble, we examine two distinct periods: 1950–1979, with relatively stable temperatures due to aerosol-induced cooling offsetting greenhouse gas warming, and 1985–2014, marked by rapid warming. During 1950–1979, heatwave trends were weak and non-robust, with internal variability explaining over 80% of the variability. In contrast, 1985–2014 saw strong increases in heatwave frequency, duration, and intensity (>0.15 heatwaves season−1 decade−1, >0.3 days season−1 decade−1, >0.3 °C season−1 decade−1, respectively), largely driven by greenhouse gases, with internal variability’s role declining to ~30%. This recent intensification is primarily modulated by enhanced clear-sky longwave radiation, anticyclonic circulation, and increased atmospheric moisture.