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. 2024 Mar 1;64(3):gnad050.
doi: 10.1093/geront/gnad050.

Population Aging and Heat Exposure in the 21st Century: Which U.S. Regions Are at Greatest Risk and Why?

Deborah Carr  1 , Giacomo Falchetta  2   3 , Ian Sue Wing  4
Affiliations

Population Aging and Heat Exposure in the 21st Century: Which U.S. Regions Are at Greatest Risk and Why?

Deborah Carr et al. Gerontologist. .

Abstract

Background and objectives: The co-occurring trends of population aging and climate change mean that rising numbers of U.S. older adults are at risk of intensifying heat exposure. We estimate county-level variations in older populations' heat exposure in the early (1995-2014) and mid (2050) 21st century. We identify the extent to which rising exposures are attributable to climate change versus population aging.

Research design and methods: We estimate older adults' heat exposure in 3,109 counties in the 48 contiguous U.S. states. Analyses use NASA NEX Global Daily Downscaled Product (NEX-GDDP-CMIP6) climate data and county-level projections for the size and distribution of the U.S. age 69+ population.

Results: Population aging and rising temperatures are documented throughout the United States, with particular "hotspots" in the Deep South, Florida, and parts of the rural Midwest. Increases in heat exposure by 2050 will be especially steep in historically colder regions with large older populations in New England, the upper Midwest, and rural Mountain regions. Rising temperatures are driving exposure in historically colder regions, whereas population aging is driving exposure in historically warm southern regions.

Discussion and implications: Interventions to address the impacts of temperature extremes on older adult well-being should consider the geographic distribution and drivers of this exposure. In historically cooler areas where climate change is driving exposures, investments in warning systems may be productive, whereas investments in health care and social services infrastructures are essential in historically hot regions where exposures are driven by population aging.

Keywords: Age structure; Climate change; County-level analyses; Geographic differences.

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Conflict of interest statement

None declared.

Figures

Figure 1.
Figure 1.
Percentage of population aged 69+: (A) annual cooling degree days, (B) 95th percentile of 20-year daily maximum temperatures, (C) contemporary indicators (1995–2014), and (D) projected change by 2050, based on SSP585 assumptions. Notes: CDD = cooling degree days, a measure of cumulative heat exposure over a year (left column); TMax95 = 20-year 95th percentile of maximum daily temperatures measures acute exposure to heat extremes (right side).
Figure 2.
Figure 2.
Relative contributions of climate change, population growth, and population aging to person degree days, by U.S. Census regions, 2050.
See this image and copyright information in PMC

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