Why older adults are especially vulnerable to climate change

When Hurricane Katrina devastated New Orleans in 2005, people ages 60 and older accounted for 75% of the deaths.

During the Pacific Northwest heat wave of 2021, most of the nearly one thousand who died were older adults. People over age 65 accounted for three-quarters of the deaths in Washington state; in Oregon's Multnomah County, the average age of the dead was 70.

In the deadliest U.S. wildfire in more than a century - at Lahaina, Hawaii, in 2023 - more than two-thirds of the approximately 100 fatality victims were 60 and older.

That data is typical of what happens after environmental disasters and extreme weather events, be they hurricanes, heat waves, freezes, pollution, floods, or the spread of vector-borne diseases: Older adults often get injured, sick, or killed more than people in other age groups.

"When you look at Katrina, when you look at Hurricane Sandy, when you look at wildfires - the vast majority of the casualties and the victims of these disasters tend to be older adults," says Samir Sinha, MD, geriatrician and clinician scientist atUniversity Health Network in Toronto.

The vulnerabilities seem likely to expand as climate change fuels more severe weather. A study by the Yale School of Public Health of deaths in 50 countries projected that as the earth's temperatures continue to become more extreme, the aging of the planet's population will "substantially amplify future heat- and cold-related deaths."

The Lancet's 2023 report on health and climate change calculates dire impacts from heat alone: It projects that between 2041 and 2060, annual heat-related deaths for those older than 65 will increase by 370% above 1995-2014 levels, even if global temperatures rise by only 2 degrees Celsius.

When Matthew Nelson, MD, a geriatrician at St. John's Nursing Home who is affiliated with the University of Rochester Medical Center in New York, ponders the many challenges that climate change and extreme weather events pose to older adults, he sees a common theme: less ability to adapt quickly to those changing conditions.

"Their response time is slower, both internally and externally," Nelson says.

Internal responses are biological, while external responses are how people interact with their environment.

Internal risk factors

Temperature regulation: Aging changes the body's ability to respond to heat and cold.

"As we age, we have a reduced ability to thermoregulate our bodies," says R. Sean Morrison, MD, chair of the Brookdale Department of Geriatrics and Palliative Medicine at the Icahn School of Medicine at Mount Sinai in New York City. "Sweating capacity decreases as we get older, so we're less able to cool ourselves when things get very hot. Blood flow to the extremities decreases, so we aren't as able to dissipate heat as we were when we were younger."

As for coping with extreme cold, Morrison notes that body fat decreases in older age, so "you lose the ability to insulate yourself."

Older people also tend to be on more medications than younger people are, and "many of those medications interact with each other and affect how their bodies respond to heat," says Jeremy Martinich, MS, chief of the Climate Science and Impacts Branch of the U.S. Environmental Protection Agency's Climate Change Division."It changes how their circulatory system works. It changes their body's ability to regulate its temperature."

Compounding those effects, Nelson says, is that people's perception of heat and cold gets blunted as they age, making them slow to realize that they are dangerously hot or cold.

These factors increase the risk of heat illnesses, from swelling and cramps to heat exhaustion and heatstroke.

Comorbidities and weakened immune systems: People tend to develop more chronic health conditions as they age - such as cardiovascular, cerebral, and respiratory diseases - which can be exacerbated by extreme weather and environmental conditions, like increased heat and pollution. Air pollution exacerbates pulmonary disorders, Martinich says. Morrison notes that stress from extreme heat and cold "can result in increased heart rate and decreased blood pressure."

In addition, the weakening of immune systems that comes with advanced aging makes it harder for older adults to fight off infections, Nelson says.

One example is Lyme disease. Older adults are the most likely age group to get Lyme disease and get severely ill from it, according to the Centers for Disease Control and Prevention. One might think ticks are most likely to latch onto young children playing in their yards and young adults hiking through woods. But warmer temperatures and extended spring seasons in many areas are expanding where and how long ticks and other insects can thrive, which is spreading Lyme and other diseases to populations not accustomed to them.

Sinha says older adults are often bitten by ticks in or around their homes but don't know it. They don't think to examine themselves for ticks, and their limited joint mobility might make that especially difficult.

"That requires someone like a partner to help you tick check thoroughly. It requires a lot of bending and maneuvering," Sinha says.

Cognitive impairment: Dementia and other types of cognitive impairment can interfere with someone's comprehension of risks and the ability to protect themselves. Morrison says that stress, such as from heat or severe weather events, can temporarily worsen existing cognitive impairments.

"For someone with dementia, all of this [the risks] gets exacerbated," Morrison says. "They might not remember they're thirsty. They might not remember to turn on the air-conditioning."

Extreme environmental effects can also fuel the development of long-term cognitive impairment. A study published last year, conducted by schools of public health together with the University of Michigan Medical School, found that exposure to fine particulate matter (such as that produced by wildfires) increases rates of dementia. Other studies link air pollution to an increased risk of Alzheimer's disease.

Decreased mobility: As they journey through old age, many adults need more help getting from here to there. If their gaits become unsteady, heavy rain and ice pose heightened hazards. Some use wheelchairs or walkers. Perhaps they don't drive anymore.

"You're more likely to be living with physical impairments that make it harder for you to get around," Sinha says.

When there's a severe storm or flood, or when the air outside is unhealthy because of heat or high ozone levels, many older people have no way to get to health care appointments or shop for food. Even if they want to evacuate because of dangerous conditions, they often have no means to do so, Sinha notes. That struggle is playing out now in North Carolina: Doctors are trying to reach countless people, including many older adults, with severe health conditions who have been homebound since Hurricane Helene wreaked havoc there weeks ago.

External risk factors

Dependency and isolation: Older adults, even if they live independently, are more likely than younger people to require help from others for day-to-day tasks, such as getting to pharmacies or medical appointments and tending to personal care at home. (This dependence is often related to limited mobility.) In addition, older adults are more likely than those in other age groups to live alone or to live only with other older adults, such as a spouse.

That dependence and isolation increase health risks, especially during a climate-related emergency, when even minimal interpersonal interactions disappear as people in an older person's support network - from friends to visiting nurses - stay home or evacuate. The absence of those supports increases the burden on older adults to monitor their own health, notice problems, and get medical care.

"The dependency on others makes older adults more vulnerable," Nelson says.

That can be dangerous if someone slides into distress but has no one around to notice the danger and take action. "That leads to more potential for things to go wrong without having someone to step in and say, 'We need to get you some help,'" Martinich says.

Economic insecurity: About one-third of older adults are economically insecure, meaning that they fall below 200% of the federally defined poverty level, according to the U.S. Census Bureau. Older adults often live on tightly fixed budgets. As a result, Morrison notes, "maybe you don't have money to pay the electric bill. You don't have money to buy an air conditioner. You don't have money to turn the heat up."

Access to medications: If an older person with limited mobility and a fractured support network runs low on their medications during a weather or climate crisis, they often have few options to refill those medications. The pharmacy and doctor's office might be closed, Sinha notes, and they might not be able to get there anyway.

Dependence on electricity: Everyone suffers when their electricity goes out, but for older adults with severe medical conditions, a power outage can threaten their health or even their lives. No air-conditioning leaves them stuck in a dangerously hot home; no refrigeration makes some medications expire quickly; respiratory devices, heart and blood pressure monitors, and dialysis machines don't work.

Sinha says the American Red Cross (for which he serves on its Scientific Advisory Council) recommends that people who depend on electricity for their health care needs plan for an alternative power supply, such as a generator.

Mitigating the harm

Most efforts to help older adults cope with increasingly extreme weather events and hazardous environmental conditions are organized by federal, state, and local government agencies, and are aimed at people of all ages who are particularly vulnerable. These efforts include health and social services departments; police, fire, and emergency-response units; social service agencies; and power companies.

Perhaps the broadest effort is the Department of Health and Human Services' emPower program, which uses medical data to help local agencies reach out to people who might be especially at risk during severe climate events. Arnab K. Ghosh, MD, MSc, an assistant professor of medicine at Weill Cornell Medical College in New York City, explains that emPower helps emergency planners reach out to people who have special needs, such as being on a home dialysis machine or needing a wheelchair to leave home.

For example: As Hurricane Matthew approached Florida in 2016, state health and emergency-response agencies used emPower data to contact thousands of Medicare beneficiaries about their health needs and coordinate support services for them to stay home or evacuate.

Other efforts focus on strengthening community supports for older adults. New York City's Be a Buddy program recruits volunteers to develop relationships with elderly neighbors, especially those who live alone, lack air-conditioning, and have chronic health or serious mental health conditions. In Philadelphia, a block captain program recruits volunteers to routinely check in on residents, especially those who are older, during severe climate events and refer them to resources.

Several states, such as Florida, have enacted laws that require pharmacies to provide people with 30-day supplies of prescription medications in advance of severe storms. A report by the American Red Cross about disaster preparedness for older adults recommends that every state adopt such a policy.

Staff at some academic medical systems have created their own small programs to help. At the Brookdale Department of Geriatrics and Palliative Medicine in the Mount Sinai Health System, clinicians ask patients if they have home air-conditioning and help to acquire it for those who do not. Mount Sinai's student-run free health clinic, the East Harlem Health Outreach Partnership, distributes air-conditioning units to patients in need, many of whom are older adults.

But there are few if any overarching endeavors to help older adults cope with the impacts of climate change.

"We haven't talked about the impact we're seeing on this vulnerable population and what should we be doing now to address their needs," Morrison says. "That's what we should be doing."