An inference approach for assessing place-based vulnerability to heat mortality

A global increase in the frequency, severity, and scale of extreme heat raises concerns about human vulnerability to climate change and associated mortality. Heat vulnerability and mortality have largely been studied separately, lacking an understanding of their causation. Here, we create a non-parametric generalized inference approach that links socioeconomic, environmental, and infrastructure factors articulated in vulnerability theory and heat mortality between 2010 and 2020 for counties across the United States. We find that the lack of vegetation coverages drives mortality in the Southern U.S. and among Hispanic people. Limited air conditioning is a key factor in heat-related mortality among White people and the Northern U.S. A combination of poverty and education influences the heat mortality in the Southeastern U.S., while poverty is critical to the heat mortality of Black people. We also find that the effects of vegetation and air conditioning in reducing heat mortality have been on the rise in the past decade. However, socioeconomic factors, in particular poverty and education, remain the most influential constraints. To further explain this transition, a series of regression models is created. The results show that improving 1% in vegetation coverage or air conditioning installation rate can effectively complement the 1.16% negative effect of socioeconomic constraints on heat mortality. A 1% increase in vegetation area is found to be comparable to a 1.5% increase in air conditioning installation in terms of reducing heat-related mortality. Our findings bridge the gap between heat vulnerability theory and mortality, emphasizing the importance of location-based strategies and nature-based infrastructure in mitigating the health burden of extreme heat.