Projections and uncertainty analysis of socioeconomic exposure to compound dry and hot events under 1.5℃ and 2.0℃ warming levels across China

Climate change is expected to intensify compound dry and hot events (CDHEs) in China, exacerbating socioeconomic exposure to CDHEs. Based on 23 global climate models (GCMs) data from Coupled Model Intercomparison Project 6 (CMIP6), this study analyzes and projects the socioeconomic exposure to CDHEs and its influencing factors under 1.5℃ and 2.0℃ global warming levels. The results show that the frequency of CDHEs is expected to be higher under 2.0℃ warming levels than that under 1.5℃ warming levels. Population exposures to CDHEs are projected to increase by 160 × 10⁶ persons-months (about 280%) and 210 × 10⁶ persons-months (310%) under 1.5℃ and 2.0℃ warming levels, respectively. The region with the highest increase in population exposure to CDHEs is East China, followed by Central China and South China; and the regions with the smallest increase in population exposure are Tibet, Inner Mongolia, and Xinjiang. GDP exposures are expected to increase by 24 times and 20 times under 1.5 °C warming levels for SSP2-4.5 and SSP5-8.5 scenarios, while the values would be up to 38 times and 28 times under 2.0 °C warming levels. The climate effect (accounting for 80%) is the determinate factor that triggers the change of population exposure to CDHEs, followed by the interaction between the population and climate changes, while the influence of the population factor is the least. Interactive effect contributes the most to GDP exposure whereas climate change contributes the least. Across most regions of China, the warming level is the main uncertainty source, accounting for 46.1% and 70.5% of the population and GDP exposure, respectively. The results are beneficial for identifying hotspots of vulnerable regions exposed to CDHEs and provide beneficial information for conducting climate change mitigation and adaptation strategies.