Projection of Population Exposure to Compound Extreme Climate Events in the Yangtze River Basin

Compound extreme climate events may profoundly affect human activity in the Yangtze River Basin. This study analyzed the long-term spatiotemporal distribution characteristics of compound heatwave-drought and heatwave-waterlogging events in the Yangtze River Basin using multi-period historical observation data and future scenario climate model data. It also examined the changes in population exposure to compound extreme climate events in the basin and their driving factors by combining population statistics and forecast data. The results show that the occurrence days of compound heatwave-drought and heatwave-waterlogging events in the Yangtze River Basin have shown a significant upward trend both in historical periods and future scenarios, accompanied by a marked expansion in the affected areas. Compared to historical periods, population exposure in the Yangtze River Basin under future scenarios is expected to increase by 1.5–2 times, primarily concentrated in the key urban areas of the basin. The main factors driving the changes in population exposure are the increased frequency of extreme climate events and population decline in future scenarios. These findings provide scientific evidence for early mitigation of meteorological disasters in the Yangtze River Basin.