Future Population Exposure to Extreme Precipitation Slows Down in China’s Urban Agglomerations Despite Global Warming

Global warming intensifies regional extreme precipitation, escalating fatalities. However, the risk trend to regional populations from heavy rainfall remains uncertain due to declining populations in some areas. Here, we investigate both the frequency of extreme precipitation (EPF) and the associated population exposure (EP-PE) across four major urban agglomerations (UAs) in China for the historical record and future scenarios. Both EPF and EP-PE exhibit upward trends in most UAs over three decades, though their spatial high-value patterns diverge due to heterogeneous population distribution. Using an innovative precipitation percentile mapping method applied to the NEX-GDDP-CMIP6 dataset, we find that EPF is expected to increase across all emission scenarios, but EP-PE will initially rise before decelerating, with regional variations in timing of turning points. Notably, under low greenhouse gas emission scenarios, EP-PE in the Yangtze River Delta and Chengdu-Chongqing UAs is projected to decline by the end of the century. These findings underscore the role of urban demographic changes in shaping climate risks and highlight the need for integrated sustainable strategies.