Medical expenditures under climate change and SSP-informed physiological and socioeconomic scenarios in China

Climate change is reshaping global health burdens, but its financial impacts through increased household medical expenditures remain underexplored. This study integrated random forest techniques and 264,302 daily bank transaction data from 271 Chinese cities (2017–2019) to simulate household medical expenditure responses to climate change. To observe the heterogeneity among different cities, cities are categorized into 14 city groups based on their historical temperature and economic conditions to build simulation models. We further projected the future household medical expenditures in different cities under four Shared Socio-economic Pathways (SSPs), considering the pure effects of climate change and sensitivity changes under SSP-informed socioeconomic and physiological scenarios. We find that households in higher-income cities and cities with historically low temperatures have enhanced resilience to heat and cold, respectively. Climate change is projected to slightly decrease household medical expenses in China by 5.2% (SSP126) to 5.6% (SSP585) in 2060, attributed to fewer cold-related medical expenditures. Under the physiological scenarios, enhanced body system functions are projected to reduce medical expenditures by 19.5% (SSP245) to 27.6% (SSP585) by 2060. Rising incomes under socioeconomic scenarios may stimulate healthcare demand and drive expenditures up by 4.9% (SSP370) to 22.5% (SSP585). The findings highlight the importance of incorporating the moderating role of adaptation in devising tailored strategies to alleviate the household health-related economic strains induced by climate change.