Expert Commentary

How the health care sector contributes to climate change: a research roundup and explainer

The medical system is responsible for a surprisingly large percentage of greenhouse gas emissions, and the toll is especially heavy in the U.S. We look at how governments are responding and what research reveals — and offer some timely story ideas for journalists.

greenhouse gas
(fernando zhiminaicela from Pixabay)

There’s a growing realization in the health care community about the toll that the practice of medicine takes on the Earth.

The health care industry “is among the most carbon-intensive service sectors in the industrialized world,” accounting for between 4.4% and 4.6% of greenhouse gas emissions, according to a key paper on this topic, published in 2020 in Health Affairs.

In the United States, the toll is particularly heavy. It’s estimated that the health care sector produced about 8.5% of domestic greenhouse gas emissions in 2018, according to that paper. It also notes the U.S. medical system may be responsible for about a quarter of all global health care greenhouse gas emissions, which is more than the health care system of any other nation.

The Biden administration highlighted its efforts to reduce these kinds of emissions during the United Nations Climate Conference (COP27) in November. U.S. delegates announced that more than 100 health care organizations have signed the voluntary Health Sector Climate Pledge initiative that the Department of Health and Human Services created with the White House. In kicking off this initiative in June, Adm. Rachel Levine, a pediatrician who serves as assistant secretary of the Department of Health and Human Services, stressed the link between climate change and illness.

“We’re already seeing the damage done by extreme heat, wildfires, severe storms, and increasing chronic disease burdens, all associated with climate change,” said Levine in a June 30 statement.

Levine described the Health Sector Climate Pledge initiative as “the beginning of a longer ongoing effort with partners from across the industry, which is exactly the kind of big response we need as a country.”

Organizations that sign the pledge have agreed to try to reduce emissions linked to climate change by 50% by 2030, from a baseline level set no earlier than 2008.

While certainly a positive step, this White House initiative depends on the goodwill of hospital administrators and leaders of companies that make medical products. Put bluntly, it is a strictly voluntary pledge and has no guarantee of lasting beyond the Biden administration.

The organizations that signed this pledge “are not obligated to report data on their progress to the federal government in association with this pledge,” according to an FAQ on the HHS website.

Weaving environmental efforts into the practice of medicine

Some leaders in medicine have recommendations for ways to secure more lasting incentives to reduce the carbon footprint of healthcare. They want to leverage the clout of the federal government as the nation’s biggest purchaser of health care and drive changes through regulation, such as a mandate to report on efforts to address climate change.

Among those advocating for regulation is Jodi Sherman, an associate professor of anesthesiology and epidemiology at Yale School of Medicine University, who spearheaded development of the Yale Gassing Greener app. This allows her fellow anesthesiologists to easily see how much pollution they can avoid through different choices of inhalation gases during surgeries.  She also is an author of professional guidance intended to help anesthesiologists better understand how their choices of gases affect emissions, and one of many authors of the previously cited 2020 Health Affairs paper.

Sherman maintains that efforts to reduce health care’s contribution to climate change should be woven into the practice of medicine. “This is the new frontier for patient safety where we are looking beyond the patient in front of us,” she says.

In covering this topic, journalists need to dig beyond press releases and statements from health care organizations about their support for the broad goal of reducing the carbon footprint. They should press hospital leaders and executives of medical supply companies for concrete examples of their plans to reduce their organizations’ carbon footprints. And they should look at what the research says.

The United Kingdom’s Sustainable Development Unit

Researchers who have studied the health care sector’s effect on climate change suggest the United States look to a United Kingdom program as a model. 

The U.K.’s  National Health Service has been a leader for many years in keeping tabs on emissions, a key step toward reducing them. It created a Sustainable Development Unit in 2008, and began that year conducting assessments of the NHS’s carbon footprint, write Imogen Tennison and her co-authors in a 2021 article published in The Lancet.

“Regularly updated and improved upon, these assessments now constitute the longest-running effort to quantify health-care-related greenhouse gas emissions in the world,” they write of the work of the Sustainable Development Unit.

The U.S. differs from the U.K., which has a centralized government-run health system as its dominant provider of medical care. But to truly make a difference in the U.S., the federal government should require health care organizations to report on their emissions, Sherman and her coauthors argue in their 2020 Health Affairs article, Health Care Pollution And Public Health Damage In The United States: An Update.

“Mandated emissions reporting would inform science-based interventions and facilitate rapid adoption of sustainable health care practices that could dramatically reduce health care pollution and improve public health,” they write.

The United States has a complex medical system, involving a mix of public and private initiatives and laws in 50 states plus the District of Columbia, as well as regulations enforced by federal agencies. But many U.S. hospitals and medical offices depend on payments from the Medicare and Medicaid programs, which are the nation’s largest purchasers of health care.

There are at least two promising ideas for attaching emission reporting rules to Medicare payments:

  1. The Centers for Medicare and Medicaid Services could require reporting emissions data as one of its conditions for paying for health care services.
  2. There could be a mandate from The Joint Commission,  a nonprofit organization on which CMS heavily relies to check on how well hospitals are run. Loss of accreditation from The Joint Commission puts at risk hospitals’ Medicare payments, which are the financial lifeblood of many of these organizations. If the Joint Commission showed more interest in reporting on emissions, it could inspire hospital leaders to track them, even if this didn’t rise to the level of a threat to payment.

Scope 1, 2 and 3

Before we delve into these suggestions, let’s go over the widely used Scope 1, 2 and 3 framework for discussing greenhouse gases. These classifications are part of the comprehensive standardized framework created by the Greenhouse Gas Protocol, which resulted from a partnership between the World Resources Institute and the World Business Council for Sustainable Development (WBCSD).

The authors of the 2020 Health Affairs update describe these classifications in their paper as follows:

  • Scope 1 refers to greenhouse gas emissions emitted directly from health care facilities, such as from on-site boilers and certain medical gases.
  • Scope 2 covers those emitted indirectly through purchased electricity.
  • Scope 3 refers to those emitted in the supply chain through the production of goods and services procured by health systems.

For more on this, see this World Resources Institute primer.

CMS raises the question

The Centers for Medicare & Medicaid Services this year asked the public for feedback about how health organizations can track greenhouse gases, a move that signals the agency may eventually take steps in this direction.

The agency included a request for information on ways to address climate change in its draft update of the Medicare payment rule for inpatient services for fiscal 2023. CMS uses its annual payment rules as vehicles to make myriad changes in the conditions it attaches to its payments.

CMS released the proposed Medicare rule for 2023 payments for hospital inpatient services in April. (You can find all of the comments on this wide-ranging proposed rule posted here. There’s a search box that lets you home in on comments that addressed CMS’ questions on climate change. Tip for journalists who work for a regional news outlet: Try searching on the name of a state and the term “climate change”.)

Among the questions CMS posed was whether hospitals or health systems are setting “time-bound, public aims” for addressing greenhouse gas (GHG) emissions. The reactions were mixed.

Already noted as a leader in this area, the staff of the Cleveland Clinic, for example, told CMS that it has a goal to be carbon neutral by 2027, in terms of both Scope 1 and 2 emissions. The comment also said the clinic “would support the establishment of time-bound goals for GHG emissions reduction in the health care industry sector-wide.”

These statements were parts of the Cleveland Clinic’s comment to CMS on the draft Medicare payment rule. (Comments on federal rules are posted on the website, which can be a great source for journalists.)

In contrast, the American Hospital Association (AHA) urged CMS to consider the burden of potential new rules on its members, while also stating broad support for the goal of reducing greenhouse gas emissions. Older physical structures, for example, may not be able to undergo the same type of retrofitting of heating or cooling systems compared with newer ones, AHA said in a June comment to CMS.

The hospital lobbying group also questioned whether HHS “has the legal authority to impose requirements on hospitals to address threats created by climate change.

In their Health Affairs article, Sherman and her coauthors argue for using Medicare’s existing frameworks intended to judge the quality of medical care to create a system for tracking the carbon footprints of hospital systems. (See Exhibit 4 of their paper for a more detailed discussion of ways that existing CMS metrics could be expanded to address climate change.)

The Joint Commission and a proposed SEC rule

Jonathan Perlin, who became the  president and chief executive of The Joint Commission in March, discussed his plans to address climate change in an October interview with New England Journal of Medicine’s NEJM Catalyst. Perlin said decarbonization efforts are critical because “climate change is having a direct and inequitable effect on the health and well-being of people globally.”

Perlin also spoke about convening a technical advisory panel to consider this issue, in part to consider ways to encourage health systems to address reducing their own carbon footprints.

It would be wise for journalists to keep tabs on Perlin’s plans to address the carbon footprint, says Brian Chesebro, an anesthesiologist and the medical director for environmental stewardship at Providence Health Oregon. There are important stories to be written about any action The Joint Commission takes in this area, he says.

“The Joint Commission has tremendous influence over the operations of health care and tremendous influence over the leadership,” Chesebro says.

In addition, the Securities and Exchange Commission in March proposed a rule that would require many companies to disclose their greenhouse gas emissions, as well as their potential financial losses from climate change.

The proposed SEC rule applies broadly to publicly traded companies. This would include companies such as HCA Healthcare, a for-profit hospital system, which as of September owned and operated 182 hospitals. It would also apply to companies that make drugs, medical devices and health supplies.

As of December, though, the SEC had yet to finalize the proposal. And the commission faced pushback from industry groups — as well as from one of its own members.

The climate change proposal would not produce the kind of “comparable, consistent, and reliable disclosures” that the commission wanted, said SEC Commissioner Hester Pierce, in a March statement to SEC Chairman Gary Gensler. Pierce was appointed as an SEC commissioner in 2018 following a nomination by then President Donald Trump.

The SEC proposal asks some large companies to provide information about the carbon footprint of their suppliers, customers, employees and other factors such as changing weather patterns. 

In a public statement issued for a March 2022 SEC meeting, Pierce said she understands the drive to “bring clarity in an area where there has been a lot of confusion and greenwashing,” using a term for efforts to make companies and organizations seem more environmentally responsible than they are.

But Pierce questioned whether the SEC would get the results it sought from its proposal, arguing about challenges ahead in gathering reliable data and analyses.

Research roundup

In the research roundup below, we’ve gathered and summarized analyses on emissions, as well as papers outlining the challenges of gathering data on the carbon footprint of the U.S. healthcare sector.

The first two studies could be considered required reading for journalists delving into this topic, as they contain solid estimates of changes in the contribution of health care organizations to climate change in the U.K. and U.S.

The other five papers present analyses and thoughtful plans and suggestions on topics including:

  • How reducing use of over-testing and low-value treatments could help shrink the carbon footprint of U.S. health care.
  • A detailed list of actions the federal government could take to leverage its financial clout as a purchaser of health care and a supporter of medical research and training.
  • How to reduce greenhouse gas emissions due to manufacturing of medical devices
  • Reconsidering travel to medical conferences.

Health Care’s Response to Climate Change: A Carbon Footprint Assessment of the NHS in England
Imogen Tennison; et al. The Lancet Planetary Health, February 2021.

The carbon footprint of the U.K.’s NHS fell by 26% from 1990 to 2019, mostly due to reduced use of certain kinds of inhalers and in forms of energy used for heat and power, the authors write.

This was the key conclusion of what the authors describe as “the longest and most comprehensive accounting of national health-care emissions globally.” In addition to highlighting the major wins in reducing the carbon footprint, the study illustrates areas where growth in emissions was at least held in check amid rising demand for medical services.

The total tally for the NHS in England dropped from 33.8 megatons of carbon dioxide equivalent (Mt CO2e) in 1990 to 25.0 Mt CO2e in 2019, the study finds.

Among the biggest contributors to that decline was a change in production of metered dose inhalers, stemming from the 1987 Montreal Protocol, an international treaty designed to reduce production of products that deplete the Earth’s protective layer of ozone. It set in motion efforts to phase-out of chlorofluorocarbon propellants in metered dose inhalers, which are used for asthma and other lung conditions. (There are still concerns, though, about emissions from inhalers.

The carbon footprint for metered dose inhalers dropped from 4.64 Mt CO2e in 1990 to 0.80 in 2019.

The carbon footprint attributed to oil dropped from 1.74 Mt CO2e to 0.02 Mt CO2e. This analysis weighed both the reduction in the NHS’ direct consumption of oil for its energy needs, a Scope 1 use, and oil consumed in the supply chain of the NHS, the Scope 3 uses.

It’s important to note that during the study period, the population of England increased by 17% and the NHS England’s provision of care doubled, in terms of a measure as hospital stays.

The carbon footprint for travel related to the NHS did tick up during the 1990-2019 period, rising from 1.9 Mt CO2e to 2.4 Mt CO2e. This figure includes commutes by NHS staff as well as trips by patients and visitors.

In the paper, the authors highlight the 2008 creation of the NHS’ Sustainable Development Unit, which has closely tracked carbon footprint, as a contributor to their analysis.

“Regularly updated and improved upon, these assessments now constitute the longest-running effort to quantify health-care-related greenhouse gas emissions in the world, and are notably the only national-level analyses carried out by a public agency with institutional support, rather than by independent researchers,” the authors write.

To hear Tenninson and co-author Matthew J. Eckelman discuss this paper, check out this episode of the Lancet’s Planetary Health podcast.

Health Care Pollution And Public Health Damage In The United States: An Update
Matthew J. Eckelman; et al. Health Affairs, December 2020.

U.S. health care greenhouse gas emissions rose 6% from 2010 to 2018, reaching 1,692 kg per capita in 2018 — the highest rate among industrialized nations, the authors write. In other terms, they reached about 553 Mt CO2e in 2018, or approximately 8.5% of domestic U.S. greenhouse gas emissions, the authors write.

This figure — 8.5% — has been widely cited, including by the White House in its June statement on the Health Sector Climate Pledge.

In making these estimates, the authors used data from the Environmentally-Extended Input-Output model (USEEIO), developed by the EPA. This model melds data on economic transactions between 389 industry sectors, with emissions data that the EPA describes as “a wealth of environmental information, including data on land, water, energy and mineral use, air pollution, nutrients, and toxics.”

The paper also includes estimates of state-level emissions. Midwestern and Northeastern states generally have higher per capita emissions than Western or Southern states, the authors report.

Their calculations also suggest that in 2018 greenhouse gas and toxic air pollutant emissions resulted in the loss of 388,000 disability-adjusted life-years (DALYs). DALY is a tool researchers use to show a broader picture of the effects of a harmful substance or practice on people. (The World Health Organization explains that a DALY represents the loss of the equivalent of one year of full health. DALYs for a disease or health condition are the sum of the years of life lost to due to premature mortality and the years lived with a disability due to prevalent cases of the disease or health condition in a population, the WHO explains.)

This disease burden is “within the same order of magnitude as years of life lost as a result of deaths from preventable medical errors and it remains a concerning issue for health care safety, quality, and cost containment efforts,” the authors write.

Why Climate Activists Should Care About Healthcare Waste and Overuse
Daisy Valdivieso and Thomas B. Newman. The Journal of Climate Change and Health, October 2022.

The authors call for greater efforts to reduce use of medical tests and procedures that are considered unlikely to deliver significant benefit as an easy way to shrink the carbon footprint of medical care.

They cite the work of the The American Board of Internal Medicine’s Choosing Wisely program as a resource in weighing what tests and procedures patients and clinicians should consider skipping. Choosing Wisely collects recommendations from specialists who have reviewed studies about treatments and tests commonly used in their fields.

This approach also plays more to the strength of people practicing medicine than do strategies more focused on reducing energy consumption in a broad sense.

“Emissions from buildings, ventilation, and lighting are not healthcare workers’ area of expertise, but we do have expertise in identifying low-value care,” the authors write. “Drawing connections between the high cost of healthcare and healthcare waste can help draw urgency to the matter.”

Prescriptions for Mitigating Climate Change–Related Externalities in Cancer Care: A Surgeon’s Perspective
Victor Agbafe; et al. Journal of Clinical Oncology, March 2022.

This paper provides an overview of efforts underway in medicine to reduce emissions of greenhouse gases, with an emphasis on cancer surgeries. Its suggestions include ways to reduce emissions from operating rooms such as scheduled preventive maintenance.

It also touches on efforts to avoid unnecessary waste in the surgical supply chain. Trays of instruments prepared for operations sometimes have unnecessary or rarely used sterile instruments, which could be weeded out by more selective preparation, the authors write.

Confronting Health Care’s Climate Crisis Conundrum : The Federal Government as Catalyst for Change
Kenneth W. Kizer and Kari Christine Nadeau, JAMA, January 2022.

In the Viewpoint article, Kizer and Nadeau urge a broad application of what’s been learned about quality metrics to efforts to reduce the carbon footprint of the U.S. health care sector.

More public reporting is needed to understand the scope of the problem and identify solutions, the authors write.

“First, the president could direct all federal agencies that provide health care to begin reporting on the environmental and societal consequences of their operations in accordance with the Global Reporting Initiative framework and standards for environment, social, and governance (ESG) reporting,” they write.

“Government health systems do not disclose these data (and very rarely do private health care organizations), unlike more than 90% of the Standard & Poor’s top 500 companies and many nongovernment entities,” they add.

Other suggestions include:

  • Direct CMS to require all recipients of Medicare, Medicaid, and the Children’s Health Insurance Program funds to begin ESG reporting.
  • Have the VA and the Defense Department require ESG reporting from the private health care providers with whom they contract.
  • The Food and Drug Administration could include ESG reporting as a requirement in applications for approval of new medicines and medical devices. Kizer and Nadeau write that the U.K.’s National Health Service and its equivalent of the FDA — the Medicines and Healthcare Products Regulatory Agency — already do this.
  • The federal government could require that institutions receiving research funds from the National Institutes of Health, Department of Defense, or other federal government agencies report on ESG performance and develop sustainability plans. The government could also leverage its role as the biggest funder of physician training, graduate medical education and other health professional training, to demand climate change education be included in the curriculum of programs.

“This could constitute a substantial step toward better equipping health professionals to confront climate change and other planetary health problems,” they write. Educational institutions receiving such funds also could be required to report on ESG performance.

Estimation of the Carbon Footprint Associated With Attendees of the American Psychiatric Association Annual Meeting
Joshua R. Wortzel; et al. JAMA Network Open, January 2021.

The American Psychiatric Association (APA) saved the estimated equivalent of burning 500 acres of dense forest, or 22 million pounds of coal, when it opted for a virtual annual conference in 2020 due to the pandemic, the authors write.

There’s tension between the APA’s having made a priority of addressing the effects of climate change on mental health, while holding one of the world’s largest annual psychiatric conferences, according to the paper.

With that in mind, the authors created a study that included data from the APA about the cities and countries of origin of about 16,620 attendees at the 2018 annual meeting and about 13,335 at the 2019 annual meeting.

The authors then identified likely transportation modes and departure airports for each attendee based on their distance from the meetings. Estimates for emissions for attendees considered to be within driving distance were based on Environmental Protection Agency’s guidelines. For flying emissions estimates, the authors used the Flight Emissions API (GoClimate) web tool. They concluded that the 2018 New York City and 2019 San Francisco APA annual meetings produced an estimated 19,819 and 21,456 metric tons of CO2e emissions, respectively.

This analysis was not meant to discourage in-person conferences, but to spark consideration of ways to reduce their carbon footprint, the authors write. “Creative workarounds” such as greater use of virtual meetings should be considered, they conclude.

Transforming The Medical Device Industry: Road Map To A Circular Economy
Andrea J. MacNeill; et al. Health Affairs, December 2020.

The authors of this analysis argue for a shift toward more reusable products, which might be less profitable for some manufacturers but better for the planet. “Single-use blood pressure cuffs, for example, have been introduced to obviate the need for cleaning, despite little evidence that reusable cuffs are significant vectors of pathogens when properly reprocessed,” the authors write.

They write that despite broad adoption of single-use disposable products, there is no compelling evidence that they reduce infections acquired during surgery or other health care.

“Most of the decrease in surgical site infection rates from 4–6 percent in 1987–90 to 2 percent in 2009 can be attributed to the use of evidence-based protocols to standardize care and enhance host defense mechanisms (for example, glycemic control and normothermia),” they write.

They argue for an “expanded notion of patient safety that considers population health,” and which “would take into account the social and environmental damages of the current single-use disposable–dominant health care supply chain.”

The authors argue that regulators should take responsibility for the safe sale and reuse of medical devices. They could, for example, restrict single-use disposable labeling to products for which safe reuse cannot be reasonably demonstrated, instead of allowing single-use disposable labeling by default.

Additional resources

Commonwealth Fund’s Climate Change and Health Care initiative website:                      

This respected nonprofit organization is seeking to help health systems with tools, and resources to reduce their carbon emissions. It also is supporting new academic research to measure, compare, and reduce the health system’s carbon footprint. Among its recent publications of interest to journalists are:

National Academy of Medicine’s Action Collaborative on Decarbonizing the U.S. Health Sector: A leading U.S. coordinator of health care initiatives is seeking to help medical organizations share ideas for reducing their carbon footprints. Its plans include holding meetings and seeking other ways to share suggestions.

American Medical Association (AMA) Climate Change website: The largest organization of doctors in the United States has been speaking in support of efforts to reduce emissions. It has called on doctors to assist in educating patients and the public on the physical and mental health effects of climate change and on environmentally sustainable practices, and to serve as role models for promoting environmental sustainability.

Agency for Healthcare Research and Quality is a federal agency that tries to have medical practices supported by research used more widely in health care. AHRQ contracted with the nonprofit Institute for Healthcare Improvement (IHI) to develop a primer with suggestions for reducing emissions.

Health Care Without Harm: A global group with a U.S. operation that seeks to help reduce the environmental footprint of the health care sector.

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