Healthcare and Climate Change

MHE PublicationMHE July 2023
Volume 33
Issue 7

Emissions from healthcare facilities contribute to climate change, and climate change, in turn, is presenting new challenges for healthcare.

In the urgent rush to prepare for and mitigate climate change, the healthcare sector has more than a dog in the fight — it has a kennel full of them. But what’s not certain is whether healthcare systems, insurers and the other major players will rise to the challenge.

“I’m worried about the next couple of decades, because of our lack of preparedness,” says Kristie Ebi, Ph.D., M.P.H., a climate health specialist at the University of Washington and a co-author of several national and international climate reports. “The weather affects our health directly when it’s hot or cold, when there is extreme weather and climate events — when there is flooding, for example — or drought,” she added.

Many in the healthcare community agree that climate change health battles are now raging on many fronts. In December 2022, extreme weather dumped 43 inches of snow on Buffalo, New York, stranded many ambulances and was blamed on climate change–induced jet stream instability. Last month, much of the eastern U.S. was blanketed in smoke from Canadian wildfires that were the result of abnormally dry and warm temperatures that can be traced to changing weather patterns produced by climate change.

Occurrences like these are a new normal that healthcare systems must prepare for, according to a 2021 Lancet editorial, cosigned by 200 medical journals. “In the past 20 years, heat-related mortality among people older than 65 years has increased by more than 50%,” the editorial states. “Higher temperatures have brought increased dehydration and renal function loss, dermatological malignancies, tropical infections, adverse mental health outcomes, pregnancy complications, allergies, and cardiovascular and pulmonary morbidity and mortality.” The editorial also states that many vulnerable populations are disproportionately affected, including the young, the elderly and the poor.

If the healthcare sector staggers under the burden of preventing and treating climate change-induced illness, it will have itself partly to blame. Hospitals and other healthcare centers are not minor contributors to greenhouse gas emissions, accounting for as much as 8.5% of the annual carbon footprint in the U.S. That’s not only from electricity, gas, heating and cooling; there are also dozens of indirect inputs to the medical emissions.

Consider endoscopies. A huge number of single-use products are consumed during the 18 million endoscopies performed each year in the U.S. The manufacturing, transportation and handling of those products all add to the emissions toll. The annual waste, which is equivalent to the weight of 25,000 passenger cars, would cover 117 soccer fields to a depth of 1 meter, lead author Sathvik Namburar, M.D., a resident at Yale School of Medicine, and his colleagues calculated for a study published in 2021 in Gut.

Emissions reduction can be accomplished only by a mandatory system of standards and measures, argued an editorial published late in 2022 in the New England Journal of Medicine. “Voluntary pledges and initiatives will not be adequate to reach net-zero healthcare goals,” wrote lead author Hardeep Singh, M.D., M.P.H., co-chief of the Health Policy, Quality and Informatics Program at the Center for Innovations in Quality, Effectiveness and Safety at Michael E. DeBakey VA Medical Center in Houston.

Healthcare insurers

Publicly available information about how well prepared the health insurance industry is for climate change is scarce, but a 2014 report by Ceres, a sustainability consultancy, says the sector has fallen behind its peers in the insurance field and will remain in the climate change line of fire unless forecasts, premiums and policies are adjusted to reflect the new realities of a warming planet. “Failing to do so would be impudent,” says the Ceres report.

In California, half of the state’s inpatient bed capacity is located less than 1 mile from a high fire threat zone. The proximity means not only endangerment to property and buildings but also hospital evacuations at times when patient capacity is most needed.

“Health insurers need to take steps to protect policyholders from the worst impacts of climate change while also protecting their bottom lines,” Ceres warns. Such efforts should extend to divestment from “energy-intensive or -extractive industries” to ensure holdings “are not contributing to the extreme weather and air pollution that have been identified as major drivers of chronic diseases and increased mortality risk.”

Climate change is already making its presence felt on the cost side of healthcare’s ledger. System costs from pollution and global warming now exceed $800 billion a year, as measured by emergency room visits, infectious disease treatment and many other factors, according to a 2021 report from the Natural Resources Defense Council and the Medical Society Consortium on Climate and Health.

Here is a brief rundown of climate change and some of the consequences for U.S. healthcare:

Superstorm Sandy

In 2012, Superstorm Sandy not only flooded communities and overstressed hospitals in New York and New Jersey, but it also caused 11 billion gallons of sewage to flow into waterways. In its wake, there were piles of sludge, toxic blooms of mold and soaring asthma rates.

The storm was blamed for 273 premature deaths, over 6,000 hospital admissions, roughly 4,700 emergency room visits and $3.3 billion in healthcare costs, according to Sen. Sheldon Whitehouse, a Rhode Island Democrat and chair of the Senate budget committee.


Climate change propagates not only mega storms but also longer and more intense wildfire seasons. Wildfire smoke contains fine particulate matter (PM2.5), which enters the lungs and penetrates the skin to cause and exacerbate pulmonary and cardiovascular problems. The smoke, which is carcinogenic, is also known for its toxic content of burned synthetic materials.

Smoke from the 2021 wildfire season in Canada and the West Coast rode the air currents for thousands of miles and endangered residents up and down the West Coast. This year, the fires in Nova Scotia, Quebec and elsewhere in Canada produced smoke that led to some of the worst air quality on record in New York, Philadelphia, Chicago and other U.S. cities.

Healthy individuals exposed to wildfire smoke in California in 2020 were found to have “alarmingly increased numbers of abnormal activated immune cells in the peripheral blood,” according to a study led by Angela Haczku, M.D., Ph.D., a professor at the University of California, Davis, School of Medicine and director of the UC Davis Lung Center. These immune cells normally protect against inflammation but promote it when altered by wildfire smoke.

Infectious diseases

Warmer temperatures change the movement patterns of animals and humans, often bringing them into closer contact, which provides an on-ramp for the spread of zoonotic diseases. Climate change is forcing some animals to move outside their accustomed ranges, which has the potential to introduce infectious diseases to new areas. A study published in Nature in April 2022 suggests that these “spillover hot spots” will be particularly clustered in the eastern U.S.

“As human societies expand in a progressively interconnected world and the human-animal interface is perturbed, opportunities are created, often aided by climate changes, for unstable infectious agents to emerge, jump species and in some cases adapt to spread among humans,” Anthony Fauci, M.D., former director of the National Institute of Allergy and Infectious Diseases, wrote in an opinion article for the
New England Journal of Medicine.

Ticks play host to approximately 3 in 4 of the vector-borne diseases that are reported to the Centers for Disease Control and Prevention. Chief among them is Lyme disease, which is spread by blacklegged ticks. Climate change is turning places with once-cold winters into hospitable environments for these bugs. In the U.S., private insurance claims with a Lyme disease diagnosis increased 357% in rural areas and 65% in urban areas from 2007 to 2021, according to FAIR Health, a nonprofit health information organization.


Disease-carrying mosquitoes also are on the march. In the U.S., certain types of mosquitoes spread dengue, chikungunya and Zika viruses. Malaria outbreaks have also occurred. West Nile virus, which first appeared in the U.S. in 1999, is now one of the most common mosquito-borne diseases. The fatality rate is approximately 4%, and those who recover may be more vulnerable to other infectious diseases and kidney problems.

Warming temperatures in the U.S. are not expected to bring a proportional increase in mosquito prevalence, as they prefer temperate zones and may die off in regions that become hot and dry. But climate change is a double-edged sword as it is also expected to also create new mosquito habitat in some areas of the country unaccustomed to the disease-bearing insects.

In his New England Journal of Medicine editorial, Fauci says that for years, infectious diseases were considered manageable with antibiotics and vaccines, which led to an underappreciation of the dynamism of these threats. The emergence of HIV/AIDS in the 1980s was the beginning of the end of this complacency, and COVID-19 was “the loudest wake-up call in more than a century to our vulnerability to outbreaks of emerging infectious diseases,” he wrote.

Animals don’t represent the only transmission threat. Drought and desertification will drive more human migration and crowding, spreading infections to more parts of the globe.

Skin diseases

With temperature change, many diseases of the skin are likely to become more common. Atopic dermatitis, a chronic inflammation of the skin that causes itching and scratching, arises in hot conditions and is exacerbated by wildfire smoke. Bacterial and fungal infections are more prevalent in hot weather. Hand, foot and mouth disease increases 10% for every 1 C rise in temperature, according to one study.

Increased rainfall and flooding combined with human and animal waste spills can lead to waterborne diseases, such as bacterial and parasitic infections and viruses. Warming temperatures will bring more food decay and seafood contamination from mycotoxins and phytotoxins. People shed layers of clothing in warmer weather, so climate change is expected to be associated with greater exposure to ultraviolet light and higher rates of skin cancer. An offsetting factor might be that people will spend more time indoors.

“Skin cancer represents the world’s most common cancer, and incidence rates increased substantially in the latter part of the 20th century,” Eva Rawlings Parker, M.D., an assistant professor of dermatology at Vanderbilt University Medical Center in Nashville, Tennessee, wrote in a January 2021 article in the International Journal of Women’s Dermatology. “The contributions of many factors are frequently offered to explain increasing global skin cancer rates over the last 50 years, yet climate change is frequently omitted from this conversation.”

Mental trauma

Over time, climate change will bring a permanent shift to the environment, and although extreme natural events will resolve relatively quickly, the mental trauma left behind will be a lasting problem.

A study published in the American Journal of Disaster Medicine observed New York residents who were exposed to the effects of Superstorm Sandy and found probable depression in approximately one-third of them; probable anxiety in 46%; and probable post-traumatic stress disorder (PTSD) in approximately one-fifth.

A 2021 review of 254 studies of wildfire victims published in Behavioral Sciences found that the mental health effects, particularly PTSD, persist for up to 10 years. Two separate studies of adult populations three months after wildfires found rates of PTSD, ranging from 24% to 60%. Studies have found that the rates of depression and anxiety are higher after wildfires.

These natural disasters have given rise to a new set of terms used to describe mental health conditions, including ecological grief, solastalgia (distress at environmental change) and eco-anxiety — all related to strong attachment to one’s natural surroundings.

Higher rates of hypertension, gastrointestinal (GI) disorders, diabetes, chronic obstructive pulmonary disease and asthma after wildfires have been found to accompany higher rates of mood and anxiety disorders. “The impact of wildfires on mental health cannot be ignored and should not be,” wrote the authors of the review.

Hurricane-force winds and fire tornadoes are not necessary to stir up problems. Heat waves can increase mental illness in a community by putting people under stress for days and weeks at a time. Additionally, high temperatures can disrupt sleep patterns and cause people to experience discomfort throughout the day.

Days of extreme heat were associated with an 8% higher likelihood of emergency room visits for any mental health condition, according to research findings reported in JAMA Psychiatry in 2022. The authors found a higher likelihood of emergency room visits for substance use, anxiety, stress, self-harm, mood disorders and other mental health conditions.

An accompanying editorial noted that emergency room statistics don’t tell the whole story about mental health problems induced by climate change: “The frontier … remains understanding what climatic stressors do to the mental health of the large percentage of the population that will rarely show up in clinical or hospital settings.”

What can be done

Efforts in the healthcare community to lower greenhouse gas emissions have not reached critical mass. In June 2022, a group of 61 institutions pledged to cut their emissions, but well-
intentioned promises won’t achieve much unless reporting is transparent and there are universal standards for sustainability, Singh and his co-authors wrote. More healthcare institutions need to step up to the plate, they argued: “With so few nonfederal health systems pledging to decarbonize in the absence of standardized measures, accountability and support, we risk the healthcare system failing to do its part.”

Emissions from sources in the healthcare sector are best looked at with a fish-eye lens. Most cuts are aimed at facilities, energy generation and fleet vehicles, but they comprise just 20% of healthcare sector emissions, according to Singh and his co-authors. The remainder is often overlooked and is a complex assortment of emissions related to purchased goods and services, employee commuting and many other activities associated with healthcare.

Standardized measurement tools and goals would ensure these are included in a comprehensive emissions reduction effort, the authors argue. Comprehensive standards might also help counteract “greenwashing” — making misleading or exaggerated claims about environmental efforts — and discourage sustainability efforts that are mainly window dressing and do little to reduce greehouse gas emissions.

Standards and strategic goals are exactly what a GI task force recommended in a 2022 paper in Hepatology. Recognizing the huge single-use volume of waste in their profession, they developed an outline for “a path toward an environmentally sustainable GI practice,” starting with a carbon footprint and waste generation assessment and following up with possible practice alternatives that involve outcomes measurement.

The COVID-19 pandemic was a trial run for what can happen when the healthcare system is buffeted by a major emergency. Care was triaged, FDA resources were reassigned and supply chains broke down. Supplies of critical N95 respirators initially were completely inadequate. In a recent report on climate change in the medical sector, Deloitte, the consulting firm, states that “this type of shortage can be replicated several times over when natural disasters strike a highly populated area, driving up costs, threatening timely care and reducing the effectiveness of provider emergency operations.” Still, COVID-19 may one day be looked at as an instigator for healthcare sector reform that bolstered vital resilience in the delivery of healthcare during times of crisis.

Tony Hagen is a medical, business and environmental editor and writer in Florence, New Jersey.

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