Senior Health in a Changing Climate: Unique Needs of a Complex Population

Short abstract

Health effects of climate change present different challenges to people as they age, and the risks are expected to be higher in lower-income countries. Protective actions can help.

The senior proportion of the population is growing—and growing fast. By 2050, the worldwide number of people more than 60 years of age is expected to reach 1.5 billion, or 22% of the global population; that is more than double the number in 2019, when they made up just 12%.¹ This surge stems from longer lifespans, thanks to decades of improvements in disease treatment and prevention, coupled with shrinking birth rates.^2,3

The boom will be especially pronounced in low- and middle-income countries (LMICs).² In sub-Saharan Africa, for example, the number of people more than 65 years of age is projected to grow by 218% by 2050, and in Northern Africa and Western Asia by 226%.¹ In Europe and North America, by contrast, that figure is only 48%.¹

Projected growth in populations over age 65 vary by age group and country, with LMICs and low-income nations expected to see far higher rates of growth, relative to the population in 2020. Image: Harrington et al.,² used under Creative Commons license CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/).

Global aging is occurring in tandem with global temperature increases—and with the increasing frequency of climate-related events that follow, such as heat waves, floods, and droughts.⁴ In July 2024, the European Union’s Copernicus Climate Change Service reported that the global mean air temperature across the previous 12 months was 1.64°C hotter than in preindustrial times.⁵ That global average is projected to increase to 1.66–1.97°C above preindustrial times by 2050.⁶

Extreme heat is perhaps the most direct climate-related threat older adults face.⁷ However, they also have unique needs related to mobility, cognitive decline, and other age-related concerns. Because climate change presents special risks for older people, special adaptation strategies are needed to protect them.²

Climate Change Magnifies Aging-Related Health Risks

Older adults’ heightened vulnerability to climate-related health threats—along with virtually every other health stressor—stems largely from physiological and functional changes associated with aging.^2,8,9 These physiological changes typically start when people are in their mid-60s and increase thereafter.² There is even evidence that people as young as 40 years of age may begin experiencing certain of these changes.^10,11

Older bodies are less able to dissipate excess heat through sweating and pushing blood to the skin.¹² Regulating body temperature strains the heart as it beats faster to increase blood flow to the skin. For some, this means the heart is strained even when resting. That can be especially detrimental for people with compromised cardiovascular function,¹³ and older adults have the highest incidence of cardiovascular disease.¹⁴ (Notably, during extreme cold snaps, cardiovascular injuries and deaths in older populations also increase,¹⁵ possibly due to increases in blood pressure and viscosity.¹⁶)

Age-related impairments in the body’s responses to heat stress—independent of chronic disease—may contribute to increased risk of acute adverse health events in older adults during heatwaves. Image: Meade et al. (2020),¹⁹ used under Creative Commons license CC BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Older adults as a group are likely to have not only more risk factors for cardiovascular disease, such as obesity and diabetes, but multiple chronic diseases.^2,8 A study of more than 1.75 million Scottish individuals showed that half the people more than 65 years of age had an average of two or more chronic health conditions; almost half of those more than 85 years of age had four or more.¹⁷

Besides disease, certain disabilities common in later life can also contribute to worse outcomes during climate-related emergencies. For example, hearing loss might cause a person to miss news broadcasts or warning sirens. Mobility difficulties can interfere with quickly escaping from approaching storms or fires.¹⁸ People with dementia—which includes an estimated 10% of people 65 years of age and older¹⁹—may have trouble following guidance to protect themselves during extreme heat by drinking water, dressing lightly, and sheltering in a cool place.²⁰ Moreover, impaired language ability may prevent them from communicating distress to caregivers.²⁰

More than one in five people over age 65 do not drive,²¹ potentially hindering escape from a weather-related disaster. That happened in 2005 when Hurricane Katrina hit New Orleans: A series of misjudgments by local officials caused more than 70,000 residents, most without cars, to be stranded at home.²² Many of the 1,392 who died were waiting to be rescued.^22,23 Interruptions to public transportation and delivery services may also prevent older people from getting medications and medical supplies²⁴ or vital home services, such as health care and meal delivery.²⁴

Social isolation is something many seniors face,²⁵ and it too can hamper resilience to the effects of climate change. The US Department of Health and Human Services reported in 2021 that 27% of people 65 years of age and older lived alone, and the percentage living alone increased with age.²⁶ Data from a 1995 heat wave in Chicago showed that people who lived alone were among those with the greatest risk of death, whereas having friends nearby had a protective effect.²⁷ Similarly, during heat waves in Rome between 2014 and 2019, regular phone calls and occasional home visits to isolated residents over age 80 were associated with lower death rates, compared to those of similar age without social intervention.²⁸

Essentially, many of the health effects of climate change are going to be more harmful for an older adult than for a younger adult: Power outages that leave homes dangerously hot or cold; loss of refrigeration that allows food and medications to spoil; toxin-producing molds that grow in the wake of flooding²⁹; dehydration³⁰; heat-related side effects of medications commonly prescribed for seniors, including beta blockers and diuretics^31,32; and longer pollen seasons,³³ which especially affect older noses given structural changes such as weakening cartilage.³⁴

Before homes in New Orleans were surrounded by floodwaters from Hurricane Katrina, left, residents of nursing homes near Lake Pontchartrain were evacuated, right, following an order from St. Tammany Parish. Images: © David J. Phillip/AP Photo, left; © Mari Darr-Welch/AP Photo, right.

Developing Countries Hit Hardest

LMICs are expected to take the biggest hits, in many ways, from climate change. These countries cluster in the tropics, where annual temperature ranges are narrow. That means their populations are acclimated to smaller temperature swings than those in the mid-latitudes, including most of Europe and North America, where a much wider temperature range prevails.³⁵

In LMICs, population growth for people more than 85 years of age is predicted to grow 30-fold by 2100, whereas the increase globally is projected at 8-fold. The over-75 age group is expected to expand a bit less quickly, the over-65 population the least quickly of the three groups.² These growth rates differ partly because of the smaller initial size of the older age ranges.² “Across most regions, growth rates are about 50% larger for people over 75 [compared with the population as a whole], and nearly double that again for people over 85,” wrote researcher Luke Harrington of the University of Waikato and Friederike Otto of Imperial College London in 2023.²

Harrington explains that relative age structure is determined by fertility rates over the last several decades and access to higher-quality health care, with disparities between countries translating to lower life expectancy in LMICs. “Combined,” he says, “this results in significant differences in the proportion of the population [that falls] within these increasingly older age brackets, when comparing lower-income nations against higher-income nations.”

The percentage of the population living in cities over the next few decades is expected to accelerate faster in LMICs than in wealthier countries, where development has occurred over a longer period.³⁶ Large cities are considered especially vulnerable to the adverse effects of heat waves, often reporting the highest temperatures during such events.^37,38 “Because buildings are close together, heat from not only the sun but also vehicles and industrial processes becomes trapped,” says Caradee Wright, a professor of climate change and health research at the South African Medical Research Council and a deputy editor for the Journal of Health and Pollution. Researcher Andrew Chang of Yale University explains that commonly used building materials exacerbate the problem by absorbing and then slowly releasing heat.

Yet in LMICs, adaptations such as evacuation plans and cooling centers are not usually the focus of attention, according to Wright. “The development agenda is more pressing than the climate change agenda,” she says of her South African home. In China, Mingxing Chen, a professor of urban geography at the Institute of Geographic Sciences and Natural Resources Research in Beijing, echoes her view. “Currently, [LMICs] are characterized by urbanization and industrialization, leading to energy shortages and economic development demands,” he says.

Beyond heat, climate change–induced sea level rise, storm surge, and excessive rain are also expected to take a heavy toll in LMICs, where nearly 90% of the world’s 1.81 billion flood-exposed people live—mostly in South and East Asia.³⁹ Much of this vulnerability is rooted in having large populations clustered along coastlines,⁴⁰ especially in what are known as megacities, with populations exceeding 10 million.³⁸ At the same time, Wright says, LMICs are highly vulnerable to droughts as well, given that they often depend on rain-fed agriculture to grow the food they eat.⁴¹

In 2023, Baljeet Singh, age 73, checked on his 21-acre farm in Sadhuwala, India. Heavy runoff from the upper reaches of the Himalayas, attributed to climate change by scientists,⁶⁶ caused flooding of the Ghaggar, a seasonal river. Image: © Harsha Vadlamani/Panos Pictures.

Dehydration risk is increased by droughts that diminish freshwater supplies, as well as by rising sea levels that allow saltwater to intrude into coastal aquifers, reducing the availability of potable water.⁴² Along with drought, floods and fires can also destroy food crops and increase the risk of undernutrition⁴³—a serious concern in countries where food insecurity is already rampant.⁴⁴ In areas that historically have high rates of water- and foodborne gastrointestinal diseases—cholera, dysentery, and salmonellosis, for example—higher temperatures and more frequent flooding will cause more cases.^45,46 Other infectious diseases are also expected to increase under global warming.⁴³

Taking Protective Action

Adaptation to a wider temperature variation is believed to make populations more resilient to the anticipated hotter temperatures.⁴⁷ However, even within more adaptable populations, research suggests there is variation. For example, in a study of cardiovascular deaths in Spain from 1980 through 2016, cardiovascular-related deaths during heat waves were three times higher among people more than 90 years of age than among those aged 60–74 years, although the findings suggested the population when viewed as a whole was adapting to new temperature extremes.⁴⁸

This paper points to a shortcoming of many climate change studies: classifying “older adults”—often defined as people over age 65—as a single, homogeneous group.² Harrington and Otto noted the significant difference in mortality and morbidity between people at the young end of the senior group and those in their 80s, 90s, and beyond.² For instance, in a study of Europe’s record-breaking summer heat of 2022, 18% of nearly 51,000 deaths attributed to elevated temperatures were individuals 65–79 years of age; 72% were 80 years of age and over.⁴⁹

In Europe, the summer of 2022 was hotter than baseline temperatures derived from 1991–2020, left. Heat-related mortality was higher for women than men, center, and for people 80 years of age and older, compared with those ages 65–79 and younger, right. The 95% confidence intervals are shaded in the same color. Image: Ballester et al. (2023),⁶⁶ used under Creative Commons license CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).

The World Health Organization (WHO) recommends cities and countries adopt heat-health action plans, pointing to those implemented by Portugal, England, Austria, and North Macedonia as examples to emulate.⁵⁰ These schemes typically include systems to warn residents of approaching heat waves and provide health services to vulnerable groups.⁵⁰ The WHO recommends that during a heat wave, people without air conditioning spend at least 2–3 hours per day in a designated cooling center or other cooled building, such as a shopping center or supermarket.⁵¹ However, some vulnerable groups may not have access to such centers due to, for example, a lack of transportation or to being housebound, according a report by the US Centers for Disease Control and Prevention.⁵²

New Orleans became a leader in establishing public drop-in sites following Hurricane Ida in 2021, which caused power outages that left thousands sweltering at home for days.⁵³ The city’s “community lighthouse” centers, organized by churches and community centers, are being equipped with solar panels and backup battery storage to provide power during utility outages, along with oxygen supplies and some light medical equipment. The goal is to have a lighthouse within 1 mile (1.6 km) of every New Orleans resident.^54–56

Hurricane-prone New Orleans also created one of the United States’ most robust evacuation plans—ranked among the top 10 of 50 US city plans evaluated by researcher John Renne of Florida Atlantic University.⁵⁷ Key features of effective plans include a registry of residents with special needs (e.g., mobility devices, oxygen, dialysis) and transportation resources for them, with predesignated pick-up points.⁵⁷ As part of its City-Assisted Evacuation Plan,⁵⁸ New Orleans offers five pick-up points specifically for older adults, along with about a dozen more for the general population.⁵⁹

The plans Renne evaluated include provisions recommended by the US Federal Emergency Management Agency in its guidance for emergency evacuation and shelter-in-place plans for all major cities.⁵⁹ Although the agency guidance rarely mentions either older adults or weather-related disasters specifically, relevant provisions run throughout the recommendations.

In the new US 2024–2030 National Heat Strategy, released in August 2024 and designed to promote resilience to extreme heat, older adults are recognized as one of the disproportionately affected groups.⁶⁰ But other than heat, the authors of a report for the WHO concluded that the majority of approaches they reviewed for mitigating the health effects of climate change were not specific to older people, and most of the published evidence on those health effects was indirect.⁶¹

Background: © iStock.com/David Petrus Ibars.

Integrating Health and Mitigation

The WHO report called for research to fill the gaps they identified, in conjunction with climate change mitigation measures. “There is a crucial need to harmonize the concerns of older individuals and environmental sustainability to safeguard the rights of older people, particularly given the escalating impacts of the climate change crisis,” they wrote. “We must persist in developing climate change adaptation and mitigation solutions that are both equitable and culturally appropriate, with a specific focus on older people.”⁶¹

In Africa, Wright sees hope in Agenda 2063,⁶² a long-range plan developed by the African Union (AU) to bring peace, prosperity, and sustainable development to the continent. “It includes industrialization,” she says, “but with a caveat to consider using technologies to reduce environmental pollution and create resilience against climate change.” Relevant education is another area of focus for the AU. A recent review of public health doctoral programs in Africa recommended that institutions improve interprofessional education on the health impacts of climate change and the noncommunicable diseases that so often compound the risks.⁶³ In addition, the AU and the Africa Centres for Disease Control and Prevention issued a call in 2022⁶⁴ to strengthen public health education and emergency response capacity in AU member states.

Chenghao Wang, a researcher in the Department of Geography and Environmental Sustainability at the University of Oklahoma, points to the importance of adopting a more holistic life-course perspective as climate change advances. It is not enough for city managers to create plans to accommodate older adults, he says—although that is certainly important. Instead, society must design “longevity-ready” cities that lay the groundwork for healthy aging. That was the premise of a 2021 analysis he coauthored,⁶⁵ which cited features such as walkability, healthy indoor air, and safe drinking water supplies—staples of environmental health—as key to supporting health at all ages, under all conditions.

Biography

Cynthia Washam writes about science and medicine from Stuart, Florida. Her work has appeared in many publications including Oncology Times, the Los Angeles Times, and Runner’s World.