Projections of heat-related excess mortality in China due to climate change, population and aging

Climate change is one of the biggest health threats of the 21st century. Although China is the biggest developing country, with a large population and different climate types, its projections of large-scale heat-related excess mortality remain understudied. In particular, the effects of climate change on aging populations have not been well studied, and may result in significantly underestimation of heat effects. In this study, we took four climate change scenarios of Tier-1 in CMIP6, which were combinations of Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs). We used the exposure-response functions derived from previous studies combined with baseline age-specific non-accidental mortality rates to project heat-related excess mortality. Then, we employed the Logarithmic Mean Divisia Index (LMDI) method to decompose the impacts of climate change, population growth, and aging on heat-related excess mortality. Finally, we multiplied the heat-related Years of Life Lost (YLL) with the Value of a Statistical Life Year (VSLY) to quantify the economic burden of premature mortality. We found that the heat-related excess mortality would be concentrated in central China and in the densely populated south-eastern coastal regions. When aging is considered, heat-related excess mortality will become 2.8-6.7 times than that without considering aging in 2081-2100 under different scenarios. The contribution analysis showed that the effect of aging on heat-related deaths would be much higher than that of climate change. Our findings highlighted that aging would lead to a severe increase of heat-related deaths and suggesting that regional-specific policies should be formulated in response to heat-related risks. (C) Higher Education Press 2023

Automated summary

Climate change is a significant health threat in the 21st century. However, there is a lack of research on the impact of climate change on heat-related mortality in China, especially among aging populations. In this study, different climate change scenarios were used to project heat-related excess mortality, and the contribution of climate change, population growth, and aging was analyzed. The findings showed that heat-related excess mortality would be concentrated in central China and the densely populated southeastern coastal regions. Aging was found to have a greater impact on heat-related deaths compared to climate change. The study highlights the importance of regional-specific policies to address heat-related risks.