We cannot prevent extreme weather caused by climate change in the short term, but we can—indeed must—adapt to it.

                                                                        Joanna Eyquem and Blair Feltmate1

The overall aging of populations is an increasing phenomenon across the world; entire populations are aging, while fertility is lowering and life expectancy is increasing.2 The United Nations report World Population Prospects 2019 states:

In 2018, for the first time in history, persons aged 65 years or over worldwide outnumbered children under age five .… By 2050, the number of persons aged 65 years or over globally will also surpass the number of adolescents and youth aged 15 to 24 years.3

The United Nations report also highlights that life expectancy at birth is rising and is projected to continue rising, predicting that by 2050 the global mean lifespan will be about 77 years.3 In the past few decades, population aging has become widespread, whereas historically it was localized to a few geographic areas, such as Japan and Europe.2 Today, aging populations in East and Southeast Asia, Latin America and the Caribbean, Australia and New Zealand, and Europe and North America are driving the phenomenon of global population aging.3

Of course, aging is a normal physiologic process. There are numerous changes that occur as people age, including changes to body fat distribution and thermoregulatory mechanisms, as well as a general slowing of metabolism. As we age, we also experience the combined effects of various insults to our health over our lifespan, which for some result in disease or illness. Noncommunicable diseases are common in the elderly population, representing globally approximately 426 million disability-adjusted life-years lost among those older than 70 in 2019.4 Not surprisingly, in high-income countries, polypharmacy also increases as humans age,5 further increasing the risk of adverse health effects. In addition, as people age, their social capital might decrease as they leave the work force, and they might lose family members and peers or increase their dependence on others.

Aging also increases health risks due to the effects of climate change. The most obvious impact is the decreased ability to thermoregulate in the context of extreme heat. In addition, climate-related health risks can be directly related to extreme weather events such as flooding or wildfires; older adults may be at increased risk from these owing to underlying conditions such as heart or lung disease, or because they are socially isolated or dependent on others to move to safety. In many parts of the world there are also indirect health risks due to changes in infectious disease distribution, food insecurity, or conflict. Air pollution, both a cause and a result of climate change, also has important direct and indirect impacts on human health, particularly in individuals with underlying health conditions.

Heat and aging. Climate change is primarily related to increased temperatures globally, so it is likely that heat and heat waves are the phenomena that most people think of when considering climate change. Recent extreme weather events such as the heat dome in British Columbia in the summer of 2021 have kept these concerns at the forefront of the public consciousness. That heat dome resulted in a 440% increase in mortality in community-dwelling seniors older than 50 years of age living in the greater Vancouver area during the week of June 27 to July 2, 2021.6 The 2021 Lancet Countdown states that “record temperatures in 2020 resulted in a new high of 3.1 billion more person-days of heat-wave exposure among people older than 65 years.”7

In addition to increasing the risk of mortality, heat has a morbidity impact for older individuals due to changes in their ability to thermoregulate, decreased sweating, and changes to skin blood flow.8,9 Researchers in the Netherlands showed that even when the outdoor temperature is not particularly elevated, if indoor temperature increases, older individuals experience distressing symptoms that include thirst, excessive sweating, and sleep disruption.10 A study in southern Germany found that increases in indoor air temperatures harmed elderly (mean age 80.9 years) individuals’ physical functioning as measured by habitual gait speed, chair-rise time (ie, how much time is required to stand and sit 5 times consecutively), and balance, regardless of whether or not there was a heat wave.11 As most older adults spend much of their time indoors, the risks to their health are further elevated during heat waves if adequate indoor cooling and ventilation are not readily available.

A study in Boston, Mass, found that heat waves caused a 7-fold increase in heat-illness hospitalizations in the elderly, and the impact was greatest for the first heat wave of each season.12 Older adults with chronic medical conditions who are taking medications are at further increased risk of heat-related harm, particularly when taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, anticholinergic medications, antipsychotics, or loop diuretics.8 This large US study by Layton et al showed a statistically significantly increased risk of hospitalization for heat-related illness during summer months when elderly patients were taking these medications, even in the absence of a heat wave.8

Climate change is the single biggest health threat facing humanity and the livability of the planet.

                                                                                                     Theresa Tam13

Given the evidence of health risks to seniors, the aging of populations, and the inevitability of global warming, it behooves us to be proactive and think strategically about the health system and public health response to this threat.

Emergency warning systems. A number of cities have developed heat action plans or heat warning systems intended to provide their citizens with cooling strategies and alert them to health dangers due to heat waves. Montreal, Que, implemented a heat action plan in 2004 that includes public advisories about prevention of heat-related illness, intensified surveillance, implementation of preventive measures in health care facilities, extended operational hours of pools, and opening of air-conditioned shelters.14 This heat action plan has been shown to decrease overall heat-associated mortality by 2.52 deaths per day, with the impact greatest for older adults and residents of lower socioeconomic neighbourhoods.14

Engaging health care providers. Family physicians are ideally positioned to be advocates for our older patients, and we can help them prepare for climate-related impacts.

Creating a “hot days” medications checklist for older patients with guidance about how to adjust medications during heat waves and when to call for help.

Discussing weather-related safety plans for older adults living alone.

Creating a list of vulnerable older adults; consider having office staff call these patients during heat waves, particularly the first heat wave of the season.

Reviewing signs of dehydration with older adults at visits for blood pressure or heart failure checks.

In addition to caring for community-dwelling older adults, family physicians across Canada provide care for the most vulnerable older adults living in long-term care facilities, and many of these facilities are inadequately prepared for climate-related events. We can advocate for our long-term care facilities to include cooling outdoor microclimate areas15 and “future-ready building design strategies … using combinations of passive and active cooling.”16 Ontario’s newest Long-Term Care Services standards now include “goals for environmental stewardship to mitigate the [long-term care] home’s impact on the environment”; however, there is no reference to specific adaptive strategies to protect seniors from the effects of climate change.17 Public health and primary care providers can be advocates at the municipal, provincial, and federal levels for inclusion of climate change adaptation strategies for all such policies.

Addressing climate change and its impact on the health of our aging populations could become an excellent example of the integration of clinical care and public health, or clinical population medicine. Physicians, nurse practitioners, and community health workers can play a critical role in the prevention of chronic diseases for their patients, thereby reducing their risks due to climate change as they age.

Family physicians who manage medications carefully in their older patients can educate them about how to avoid adverse effects due to medications during heat events, and help them avoid heat-related illness. Clinicians can direct senior patients and their families to public health or municipal resources to cope better during heat waves or when poor air quality is a particular concern, such as during wildfire season. Health care providers such as community paramedics, family physicians, or public health nurses can keep records of vulnerable seniors in their neighbourhoods. When there is a natural disaster, these records could be used to arrange targeted follow-up in collaboration with local public health units. Public health authorities can support the efforts of clinicians through media campaigns and informational material, as well as by advising care providers when risks are particularly high. All of these efforts, although important for each individual, are going to be integral clinical population medicine functions of health assessment, policy, and assurance18 that will promote adaptation and resilience in our health system and our aging population in the face of climate disruption.

Climate change is going to impact our communities in the short term. It is incumbent on us as health care providers to work together toward solutions that will help the most vulnerable among us adapt to climate change. It will take us all working together to make a substantive difference.

Competing interests

None declared

The opinions expressed in commentaries are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

This article has been peer reviewed.

Cet article se trouve aussi en français à la page 242.