Projecting Future Heat Stress Disparities to 2100 in the Contiguous United States

Abstract Global warming increases heat-related health risks. Historical evidence suggests disproportionate heat impacts among different regional and socioeconomic groups in the US. However, little is known about the scale of potential disparities and which populations stand to be most vulnerable under different future climate scenarios. Here, we assess county-level heat exposure, measured by Heat Index (HI) from present-day to 2100, in the contiguous US using Integrated Assessment Model results for five future warming and socioeconomic development pathways. Our results reveal stark spatial and sociodemographic disparities in present and future heat stress, mainly for people of color and those aged 65+. The large proportion of high-risk populations residing in the Southern US makes this region particularly vulnerable to HI increases, and future warming will further enlarge disparities among disadvantaged sociodemographic groups. Our findings underscore the need for considering sociodemographic factors when developing climate adaptation plans and prioritizing policy responses for vulnerable communities.