Anthropogenic climate change — the accelerated warming of the planet driven by human activities that include burning of fossil fuels and deforestation — is harming human health. Exposure to excess heat and particulate matter 2.5, or PM2.5, from air pollution and wildfire smoke increases hospitalizations and death from cardiovascular and respiratory diseases.1 Sea level rise and more frequent, intense extreme weather increase flood risks, leading to injuries, displacement and psychological trauma.2 As global temperatures increase, the emergence of pathogens and the geographic distribution of infectious diseases are changing.3 Greater water insecurity threatens food production and can lead to increased malnutrition. These impacts worsen existing health inequities and will affect people throughout their lifespans.2 The effects of climate change on intergenerational inequity are profound, with children bearing disproportionate impacts in the near- and long-term.4,5 For example, the World Health Organization estimates that children under 5 years of age bear approximately 90% of the global burden of disease attributable to climate change.6 Climate change also threatens health care delivery and access in communities as they contend with increasing disruptions to transportation, utilities, facilities and supply chain systems.3
Globally, the health care sector is responsible for 4.6% of total greenhouse gas emissions.7-9 If health care were a country, it would be the fifth-largest emitter on the planet.9 In the United States, this sector contributes 8.5% to greenhouse gas emissions.10 Reducing these emissions will help slow global temperature rise in the future and bring immediate and long-term health co-benefits by improving air quality. Poor air quality remains an underappreciated public health burden. Family physicians play a critical role in preventing and mitigating the health impacts of anthropogenic climate change on their patients and communities.
The American Academy of Family Physicians calls for action in the following areas:
Physician Level
Practice Level
Community/Leadership Level
Educational Level
Advocacy Level
Heat
Climate change is causing an unprecedented rise in ambient temperatures and extreme heat events. Heat waves are the deadliest weather event in the United States and are associated with increased morbidity and health care utilization across the lifespan.11,12 Extreme heat exposure is associated with preterm birth, low birth weight, cardiovascular and respiratory disease, ischemic stroke, renal failure, poor mental health and violence.
Children are among the most vulnerable to heat-related illnesses. Leaving a child unsupervised in a parked vehicle is a leading and entirely preventable contributor to heat-related mortality in children 14 years of age and younger.13-15 Adolescents and young adults who play outdoor sports face escalating risks of exertional heat illness and even death.16 Compared with people born in 1960, people born after 2020 are estimated to experience up to a sevenfold increase in extreme events such as heat waves, which highlights the intergenerational inequity of climate change.17
People with disabilities can have specific physiologic vulnerabilities to extreme heat and/or poor adaptive capacity when exposed to it.2 Older adults are also highly susceptible to heat-related illness due to impaired thermoregulation, chronic disease, medication use, social isolation and cognitive impairment.18 People over age 55 account for nearly 60% of heat-related deaths and the majority of cardiac deaths during heat waves.19,20 For workers of all ages, excess heat poses dangerous occupational health risks. Working in hot indoor and outdoor conditions can cause acute injuries and illnesses, including kidney disease.21
People of color, people experiencing homelessness, historically redlined communities and low-income communities have disproportionate exposure to excess heat, which exacerbates existing health inequities.5,22 Heat-related mortality is a public health threat currently, and it is projected to increase by a factor of four to 10 by the end of this century. Community and public health strategies like early warning systems, equitable access to air conditioning, cooling stations, and climate-ready and climate-resilient built environments can effectively reduce heat-related mortality.23
Extreme Precipitation and Flooding
The increase in global average temperatures has an impact on health that goes beyond the effects of extreme heat events. With continued warming, every global region is projected to experience increased frequency and intensity of extreme weather including high-precipitation events, tropical cyclones, floods and winter storms.24 In 2023 alone, the United States experienced 28 climate-related, billion-dollar weather and climate disasters, of which 26 were due to severe storm events, flooding, precipitation and winter storms.25 Extreme precipitation and flooding events result in morbidity and mortality from traumatic injuries, drowning, transportation injuries, exacerbations of chronic disease, displacement, psychological stress, toxic exposures, water contamination, infectious disease outbreaks and malnutrition.26,27 Assessing the mortality rate following these events is complex, and their true impact is often underestimated. For example, the original official death toll of 64 lives lost in Puerto Rico from the massive devastation of Hurricane Maria In 2017 appeared to be a gross underestimate.28 A household survey study found an estimated 4,645 excess deaths in the same period and considerable disruption to medical services. Health care workers, facilities and services and critical supply chains for supplies including pharmaceuticals are particularly impacted by disruptions to power, transportation and water infrastructure.
Communities affected by extreme weather events experience an inequitable degree and distribution of morbidity and mortality. A community’s vulnerability is determined by its relative risk for and exposure to extreme precipitation and flooding events and its capacity to withstand and respond to these events. People of color and low-income households reside disproportionately in floodplains, cope with higher flood insurance costs and have less access to health insurance and health care.22 Additionally, children, older adults, women, LGBTQ+ people, people with disabilities, people with medical comorbidities, first responders and other emergency workers all face disproportionate health risks from extreme precipitation and flooding events.5,27
Water Security
Climate change threatens access to clean, fresh water, which is essential for human health. Extreme variations in precipitation patterns, decreased fresh groundwater supply, diminishing snowpacks and rapid melting of glaciers are climatic trends that reduce clean water supply.28 Drought and accompanying heat waves cause the second-highest number of climate-related deaths annually in the United States.25 It also impacts health by decreasing the drinking water supply and concentrating contaminants in the remaining water sources, which can lead to increased rates of infectious diseases and greater exposure to toxic industrial pollutants.24,29,30 Drought also exacerbates food insecurity because it reduces the amount of water available for agricultural irrigation even as crops require more water due to warmer growing seasons.31
In addition to reducing access to safe, clean water, climate change is worsening an international water security crisis that disproportionately impacts historically marginalized populations and low-income countries.24,30,32 In the United States, many historically marginalized communities already have an increased risk of adverse health impacts because they lack access to safe, clean drinking water.33 Native communities that have been systematically restricted from accessing natural resources vital to their traditional way of life are particularly vulnerable to water insecurity. One example of this is the Indigenous communities in the southwestern United States that have water rights to the Colorado River but must rely on costly water delivery services because they lack adequate infrastructure to procure water from the river.33,34
Implementation of adaptive climate solutions is essential to limiting the impacts of water insecurity. Increasing investment in climate-resilient infrastructure enables access to clean, safe drinking water, protects vulnerable areas from flooding, and allows for continued operation of vital services (e.g., health care systems) during water-related disasters.24,32,33,35 Improving water conservation, particularly in drought-prone areas such as the western United States,36 and implementing early warning systems for storms and other water-related extreme weather events have been shown to reduce the damage from these events dramatically.35
Air Quality
Fossil-fuel combustion drives climate change and worsens air quality, causing multiple public health harms. Rising temperatures and changes in precipitation are expected to increase ground-level ozone and particulate matter, worsening air quality throughout regions of the United States.37 Climate change causes an increase in wildfire activity and smoke pollution, as well as longer, stronger pollen seasons that increase aeroallergens. The health effects of poor air quality are wide reaching and affect people across their lifespans. Specific impacts of poor air quality include premature death related to cardiovascular and pulmonary disease, increased hospital admissions for myocardial infarction, arrhythmia, exacerbation of respiratory disease (e.g., asthma), ischemic stroke, lost productivity from missed work and school days due to acute respiratory illness and severe allergies, and adverse pregnancy outcomes including preterm delivery and intrauterine growth restriction.37-42 These effects are caused by both chronic and acute exposure to poor air quality.40-42
Globally, poor air quality is among the top five risk factors for premature mortality.43 Each year, more than 10 million excess deaths worldwide are attributable to air pollution created by fossil fuel use (specifically PM2.5).44 Coexposure to extreme heat and PM2.5 increases mortality risk more than heat or air pollution exposure alone,45 which escalates health alarms given the increasing severity and frequency of extreme heat resulting from climate change.
Adverse health effects caused by poor air quality have a disproportionate impact on people of color and people of lower socioeconomic status because these populations tend to experience greater exposure to air pollution and have less access to health care services.22,46,47 One factor leading to inequitable air pollution exposure in communities of color is historical redlining policies.48 In the United States, the mortality burden of PM2.5 is disproportionately borne by Black people and socioeconomically disinvested communities.47 Occupational air quality risks also exist for groups who may have higher exposure to air pollutants, such as firefighters and outdoor workers. While scientific evidence is clear on the inequitable mortality risk associated with air pollution, evidence also points to opportunities to rapidly improve health equity through air quality improvement measures including creation of more green spaces and use of clean electricity (e.g., solar, wind) and transportation (e.g., electric vehicles, active transport like bicycling). Environmental modeling estimates that eliminating air pollutant emissions like PM2.5, sulfur dioxide and nitrogen oxides from energy-related sectors could prevent more than 50,000 deaths and provide over $600 billion in health benefits from avoided death and illness each year in the United States.49
Infectious Diseases
Rising global temperatures and shifts in precipitation patterns are altering the ecological suitability for numerous infectious diseases and pathogens of concern, as well as their geographic distribution. Climate change has already fueled an expanded range and increased burden of tick-borne diseases (e.g., Lyme disease) in the United States. The risk of increased distribution and transmission of tick-borne illness is projected to continue rising as summers become longer and warmer in North America.5,50 Risks for increased burden and geographic distribution of fungal diseases (e.g., Valley fever), waterborne illnesses (e.g., vibriosis) and mosquito-borne illnesses (e.g., malaria, dengue, West Nile virus, encephalitis) are also climate sensitive and threaten human health.5,51
Infectious disease impacts of climate change can disproportionately impact people who live and work outdoors, as well as Indigenous people and communities that rely on subsistence hunting and gathering.2 Moreover, climate-sensitive vector-borne disease can be especially harmful for pregnant people, contributing to fetal anomalies and other adverse maternal-child health outcomes.52 Public health interventions and investment in climate adaptation measures can reduce the burden of climate-sensitive infectious diseases. It is essential to have a climate-informed health care workforce capable of diagnosing and managing climate-sensitive infectious diseases that can integrate effectively with public health systems that promote community health.
Food Security
Climate change disrupts land-based and marine food systems, threatening all dimensions of global food security including availability, access, utilization and stability. Flooding, increased temperatures, drought, hurricanes and wildfires affect agricultural land, crop yields, and food safety and delivery, amplifying domestic and global food security risks.53 Changes in ocean temperatures, acidity and oxygenation, along with invasive species proliferation, algal blooms and loss of coral reefs, significantly compromise ocean health and decrease marine harvests, impacting the food supply for millions of people.54 Increasing global conflict destroys valuable cropland, further increasing food vulnerability.55 Outdoor agriculture workers face occupational health risks (e.g., heat-related illness) associated with decreased productivity, which can also affect food security.56 In addition, increasing atmospheric carbon dioxide levels that result from burning fossil fuels can lower the nutritional value of many staple crops, thereby increasing the risk of malnutrition.2,57
Existing inequities related to food insecurity are likely to worsen due to climate-related environmental stressors. Globally, people whose livelihoods rely on subsistence practices face the highest risks of food and economic insecurity related to climate change. In the United States, rural communities face unique risks related to food security in a changing climate. Low-income families and people of color in the United States are also disproportionately affected by food insecurity. Other disproportionately impacted groups include women, LGBTQ+ people, children, older adults, people with mental illness, people who are unemployed, people with a history of incarceration and people who do not have stable housing.58,59 While climate change threatens global and domestic food security and results in related health disparities, plant-rich food systems and dietary practices that are healthful, well balanced and nutritious are two of the most impactful individual and public health interventions to mitigate climate change.60,61
Displacement and Migration
Climate change contributes to environmental degradation in myriad ways and is projected to drive substantial increases in the movement of human populations.62 In the short term, climate-related disasters like extreme weather, floods and wildfires can displace families who must flee dangerous environmental conditions. Impacts of displacement in the aftermath of disasters can be long lasting (e.g., persistent post-traumatic stress disorder and other stress-related disorders). More insidious climate-related threats to food and water security (e.g., drought) can contribute to longer-term migration and displacement, particularly among agricultural communities.
People over age 65, children, women, LGBTQ+ people, people of color, Indigenous people and communities, and people with low income are more likely to be displaced due to climate change and face more negative impacts of displacement.2 For example, women and children displaced by weather-related events face higher risks of premature mortality, malnutrition, poor mental health and violence.63,64 Family physicians play an important role in caring for people who are coping with climate-related displacement and migration, and they must be equipped with knowledge, skills and resources specific to these situations.
Mental Health
Climate change affects mental health through direct and indirect pathways across the lifespan.65-70 Climate-related disasters and displacement can cause cascading mental health issues including higher rates of depression, anxiety, PTSD and suicidality.67,71,72 Mental health can also be adversely affected by more incremental climate change impacts, such as rising temperatures, changes in precipitation, drought and changes in air quality due to wildfire smoke and air pollution.70,73-76 Even people who have not personally experienced climate-related events or emergencies can feel anxiety, grief, anger, helplessness and other negative emotions due to awareness of the climate crisis.77,78
Prenatal exposure to air pollutants can impact cognitive abilities, and air pollution is a risk factor for mental health conditions in children.79 Children and adolescents can experience significant mental health problems in response to natural disasters and climate emergencies, particularly if their parents’ mental health is impacted.80-82 Elevated temperatures are associated with more mental health-related emergency department and hospital visits involving children, adolescents and young adults.83 Children also experience significant “eco-anxiety.”84 A survey of children and young people around the world found widespread climate-related mental health impacts that negatively affected their functioning and included anxiety, grief, rage and feelings of betrayal by adults and governments.85
The mental health impacts of climate change are not experienced equally, and groups that historically have been made vulnerable continue to be at disproportionate risk.68 How a person experiences and responds emotionally to climate change is determined, in part, by their experience of environmental stressors, social determinants of health, historical social injustices, power, privilege (including access to resources that facilitate adaptation) and other systemic factors.86-88 Thus, we can anticipate that people in the Global South, people with preexisting health or mental health conditions, people of low socioeconomic status, women, children, older people, some racial and ethnic minority groups (including Indigenous people), people with disabilities, outdoor workers and emergency responders will be particularly vulnerable to climate change’s mental health impacts.24,68,86,88-91
The sixth assessment report of the Intergovernmental Panel on Climate Change concluded with “very high confidence” that climate change has already negatively impacted mental health globally and will continue to do so and that these impacts will only get worse.24,92 The WHO, American Medical Association, IPCC, American Academy of Nursing and other bodies have recommended that the United States and other countries take actions including improving access to mental health services and clinical capacity, closing funding and research gaps, enhancing surveillance and monitoring, improving community preparation and response, and integrating mental health support with climate action to prevent and reduce mental health impacts of climate change across the lifespan.24,93-95 Efforts to address climate change’s mental health impacts must acknowledge and respond to the equity-related and moral dimensions of the climate crisis. Family physicians, particularly those in under-resourced communities, are primary sources of mental health care in the United States.96 As such, their contributions to better understanding and addressing the mental health impacts of climate change and helping to promote a climate-resilient future are essential.92
The profound effects of climate change on human health call for widespread actions to influence policies at local, regional, national and international levels.97 Family physicians can play a critical role in informing and collaborating with elected leaders and promoting research, education, community outreach, clinical services, disaster preparedness and responses, and civic engagement.98,99
Research
Family physicians provide the greatest number of primary care visits in the United States. They provide continuity of care for patients and communities, including urban, rural and disinvested populations. As trusted leaders within the communities they serve, they can lead and expand research and outreach efforts related to climate change and health. By observing their patients, family physicians can collect and provide practice data to reflect changes in population health resulting from changing climatic conditions. Simultaneously, they can lead in crafting and refining a research agenda that further investigates the following:
Family physicians can amplify their efforts through partnerships with community organizations, schools, health departments and academic health centers. The AAFP promotes policies that increase commitment to and investment in climate change research and opposes any federal or state government actions to reduce public access to environmental health research data.100
Climate-Smart and Climate-Resilient Health Care
Providing health care contributes to climate change because it consumes fossil fuels and generates toxic emissions and waste. In the United States, the health care sector contributes more than 8% of the country’s greenhouse gas emissions.10 It is estimated that the harm caused by these emissions is on par with the harm caused by preventable medical errors.101 Therefore, greenhouse gas emissions are increasingly framed as a quality of care and public health issue. The AAFP encourages health care facilities and systems to promote local and global public health by setting science-based reduction goals for greenhouse gas emissions and working toward achieving them.
The health care sector and health care professionals must adapt to climate change. The AAFP encourages health care facilities and systems to integrate prospective, compounding climate risks while preparing for and adapting to a changing climate. Increased, integrated coordination with public health partners ahead of climate-related disasters (e.g., early warning systems) can save lives and improve community resilience. Conducting climate-informed hazard vulnerability analyses and engaging in updated disaster and emergency preparedness are crucial steps to improve health care access during climate-related disasters.
The AAFP encourages family physicians to take the lead in determining what defines climate-smart and climate-resilient primary care. Transforming the health care sector to become climate smart and climate resilient will require a health care workforce that has knowledge, skills and expertise in both climate change and health and environmental sustainability. The AAFP promotes continuous investment in education on these topics at all levels of health professional education, particularly among family physicians who are currently practicing.
Climate-Smart and Climate-Resilient Communities
Beyond the walls of health care facilities, the AAFP promotes policies that empower governments, communities and private and public institutions to set ambitious, science-based greenhouse gas emissions reduction goals that improve public health. The AAFP will continue to highlight the immediate and long-term health benefits associated with decreased greenhouse gas emissions and clean air and water. It also promotes policies that enable the rapid reduction of land, atmosphere and water pollution. The AAFP opposes any actions by local, state or national governments that weaken existing stream and air protections. Furthermore, it supports policies that promote community adaptation and resilience in response to climate change and policies that improve environmental justice and climate justice.
References
(April 2024) (September 2024 COD)