Extreme heat will put millions more older adults at risk in the future

Nearly a quarter of the global population of older adults at mid-century could face extreme heat, putting their health in danger.

By 2050, as many as an additional 246 million adults age 69 and older could experience temperature extremes that exceed 37.5° Celsius, researchers report May 14 in Nature Communications. The new projection suggests that more than 23 percent of the global population of these older adults — largely concentrated in Africa and Asia — will encounter this intense heat, compared with 14 percent today.

“Protecting our older population will be increasingly critical in the years to come,” says cardiologist-epidemiologist Andrew Chang of Stanford University and the University of California, San Fransisco, who was not involved with the research. “Older adults can be exquisitely vulnerable to the impacts of heat.”

Exposure to hot temperatures is physiologically demanding, and there is a limit to how much heat the body can tolerate (SN: 8/6/2023; SN: 7/27/2022). Heat extremes are especially risky for older adults for many reasons. The aging body can’t cool off as efficiently. Older adults often have chronic illnesses that are worsened by heat, such as cardiovascular disease or diabetes. People in this age group commonly take medications that are dehydrating. And some older adults are socially isolated, are limited in their mobility or have cognitive impairments.

“It’s this kind of perfect storm of biological aging, social loneliness and then cognition that make [heat] so much worse for older people,” says Deborah Carr, a sociologist of aging at Boston University.

Carr and colleagues projected the population of those age 69 and up by 2050 and estimated the impact of climate change on the regions where these older adults will reside. The researchers assessed chronic heat exposure — prolonged exposure to uncomfortable heat — and acute exposures, which are short-lived but extreme, such as during a heat wave. The team found that chronic exposure, calculated by taking the average temperature across all days of a year and determining how many degrees each day exceed a threshold temperature of comfort, will increase worldwide by 2050.

In terms of acute heat, there will be an increase worldwide in the number of days each year that exceed 37.5° C, from an average of 10 days to around 20. There will also be a greater upper bound to how high temperatures can reach during extreme heat, depending on the region. “Both the frequency and the intensity will increase as a result of climate change,” says Giacomo Falchetta, a climate change researcher at the Euro-Mediterranean Center on Climate Change in Venice, Italy.

The team also looked at the contribution of the two factors, population aging and increasing heat, to understand which was driving the projected results depending on the region. In regions in the Global South, which have historically been hotter, a growing share of the population is aging. Regions in the Global North, which are “colder and older,” Carr says, “are experiencing more heat extremes.”

There isn’t a one-size-fits-all approach to reduce the risks from increasing heat exposure to older adults, Falchetta says, but options include strengthening health care infrastructure, ensuring sufficient nutrition and hydration, implementing heat early warning systems, providing public cooling centers and expanding green spaces and tree cover to reduce urban heat island effects (SN: 4/3/2018).

As for the study’s projections, there remains uncertainty on the climate, Falchetta says, depending on reductions in greenhouse gas emissions. Regarding the demographic changes, “these people have already been born — they are people like me,” he says. Countries need to “start planning now on how to accommodate the needs of those people in the future.”