Growing occurrence of hydrometeorological extremes in African cities and the urge for effective adaptation

Urban areas across Africa are experiencing escalating thermal stress due to mounting hydrometeorological fluctuations and environmental degradation. Characterizing and detecting these compounding stressors remains challenging, limiting their integration into resilience planning. Current diagnostic tools rely on spatially restricted or univariate indicators that fail to capture the multifaceted dynamics of these hydrometeorological and ecological vulnerabilities. To address the aforementioned challenges, we develop the Urban Vulnerability Amplification Index (UVAX), a composite, trend-based metric that integrates standardized anomalies in hydrometeorological and ecological drivers across 85 major African cities for the period 2000–2024, with projections extending to 2050 using Mann-Kendall trend extrapolation under SSP2-4.5/SSP5-8.5 emission scenario pathways. The results reveal a projected increase of a few weeks per year in the numbers of anomalously warm and cold nights in major African cities. Moreover, an asymmetrical warming is observed, characterized by a significantly faster increase in minimum night temperatures than in maximum day temperatures, resulting in a narrower diurnal temperature range and intensified nocturnal heat exposure. Finally, the study reveals that precipitation regimes are expected to intensify, particularly in tropical and Sahelian cities, thereby amplifying flood risks. The study discusses adaptive, nature-based solutions to mitigate the above risks, highlighting the urgent need for green infrastructure, passive cooling strategies, and energy-efficient building retrofits in African cities to enhance their resilience to future hydrometeorological fluctuations.