Human-induced temperature rise is driving Africa towards drought-prone climatic conditions

Kurzfassung

This study focuses on the role of human activities in shaping climate forcings and their impact on surface air temperature (SAT) and drought intensification over Africa, emphasizing the human contributions to these phenomena. Through the analysis of observations, various model experiments, and Regularized Optimal Fingerprinting detection technique, our findings indicate that human-induced factors have contributed to an increase in surface air temperatures ranging from 0.8 to 1.06C above pre-industrial benchmarks. Greenhouse gases (GHGs) emerge as the primary driver of this rise (0.47 to 0.92C), followed by land use (LU) changes (0.47 to 0.63C). In contrast, anthropogenic aerosols (Aaer) exert a cooling effect (-1.82 to -1.36C) on SAT. The analysis reveals that SAT anomalies, particularly during the industrial period, have significantly contributed to the intensification of drought-prone climatic conditions. During the pre-industrial period, the absence of anthropogenic warming kept SAT stable, resulting in mildly wet conditions (Standardized Precipitation Evapotranspiration Index (SPEI)=0.54). However, in the industrial period, the sharp rise in SAT due to GHG and LU forcings led towards significantly drought-prone climatic conditions (SPEI=-0.73), while the cooling effect of Aaer was insufficient to offset the warming trend. Estimates based on Representative Concentration Pathways (RCP) 4.5 and 8.5 suggest that the SAT over Africa could rise by around 2C and 5C, respectively, by the end of the century, highlighting the significant influence of human-driven factors in driving temperature rise. Effective management of GHG emissions, LU changes, and aerosol concentrations in Africa offers the potential to mitigate further warming and consequent drought intensification in this region.