What tobacco is to personal health, greenhouse gas emissions are to planetary health. Decades after recognizing their danger, humans continue to emit over 50 billion tons of CO2 a year. The 2022 UN International Panel on Climate Change report, "Impacts, Adaptation and Vulnerability," is unequivocal in stating that human-caused emissions have pushed us into a climate crisis. We still have the opportunity to learn from our mistakes if we act quickly. And for public health professionals, this course correction needs to begin in our own backyard with commitments to addressing the climate consequences of health systems.
A Hippocratic Oath for Climate Change
Weighing the side effects of any treatment or procedure is central to the calculus of health care. All treatments have their potential harms and many of these can be difficult to predict. Avoiding harm associated with needlessly intrusive or dangerous medical tests and treatments stems from the bioethics principle of nonmaleficence—captured in a main tenet of the Hippocratic Oath, "do no harm."
While this principle has permeated modern clinical practice at the individual level, medical professionals do not always apply it to broader conversations around the harms associated with the health sector itself. These include energy use at health facilities, emissions associated with the supply chain, and product and waste disposal. Meanwhile, there is growing concern about the accelerating health consequences of climate change. So much so that the World Health Organization (WHO) declared, in the midst of a pandemic, that climate change is humanity's biggest public health threat. Climate change affects human health in myriad ways, including amplifying non-communicable diseases, intensifying infectious disease outbreaks, and contributing to nutritional disorders.
As with many modern global health challenges, marginalized and vulnerable populations will bear the brunt of these effects. If public health and medical professionals hope to take the lead on climate action to mitigate these consequences, they must first reduce the climate effects of health systems themselves.
Scale and Sources of Health Sector Emissions
Carbon emissions from the global health sector are estimated to contribute between 4 and 5 percent of global emissions, which would make the sector the fifth-largest emitter on Earth if it were considered a country. Emissions are frequently correlated to health spending and thus, the United States is the biggest producer of health-related emissions. Put another way, the emissions of the U.S. health sector alone are roughly equivalent to 140 coal fired power plants. The environmental repercussions of health service delivery vary by country, but key emission categories include health facility energy consumption, production and disposal of medical commodities and waste, and medical transport.
The global health response to the COVID-19 pandemic has only intensified the environmental footprint of health systems. Disposal of medical waste, including personal protective equipment, test kits, and vaccine related supplies, has increased by a factor of ten. Cold chain specifications for many COVID-19 vaccines often require diesel generators for electricity or fossil-fuel-powered "absorption" refrigerators. Paired with the high prevalence of hydrofluorocarbon-based refrigeration technology, the global pandemic response has significantly worsened the carbon footprint of the health sector.
As a consumer of electric power, the health sector will benefit from the energy transformations already taking place around the world. As countries add more renewables to the mix, this will in turn decrease the total emissions by health facilities drawing on this energy through the grid. This will also have a direct effect on hospital admissions particularly for respiratory conditions.
As others have noted, however, the phrase "energy transition" has different meanings for a fossil fuel executive and the climate activist. Health organizations can use their voice and purchasing power to demand the phase-out of fossil fuels and the scale-up of clean, renewable energy sources. Frontline health workers have already begun to lead this charge, via calls for nonviolent direct action and advocacy groups.
Beyond energy consumption, the WHO has long warned that a significant portion of health resources are wasted, with estimates ranging from 20-40 percent. While these numbers are bleak, they also illustrate the potential for efficiency initiatives to lower costs, extend care to those in need, and reduce the generation of medical waste.
Not all of the health sector's emissions can be eliminated through renewable electricity sources and efficiency measures. Emissions stemming from supply chains and medical waste incineration will be hard to curtail in the near term. Emission profiles are context-specific, so determining the sources of emissions becomes the first hurdle for any health organization seeking to reduce its climate impact. Consulting firms have stepped in to fill this gap, using accounting methodologies based on the Greenhouse Gas Protocol to help organizations understand their climate footprint.
Many options exist for organizations that are seriously committed to the goal of "net zero." Some actions—such as the introduction of natural lighting and ventilation—can reduce the overall health sector's climate footprint while also yielding co-benefits for clinical challenges like infections contracted in hospital settings. Abatement strategies with potential financial or health co-benefits include:
Expansion of digital health and telemedicine
Delivery of more plant-based meals at health facilities
Reduction of hydrofluorocarbons
While the mitigation strategies described above are powerful actions the health sector can take today, there are some activities that are particularly difficult to adapt or eliminate in the near term. For these, carbon removal purchases based on standards such as the Oxford Principles for Net Zero Carbon Offsetting can be used to offset emissions. Carbon removal is now viewed as essential by the UN International Panel on Climate Change in meeting climate targets.
Companies like Microsoft, Stripe, and Shopify are leading the way in establishing criteria for high-quality carbon removal that is durable and verifiable. The precedent set by these companies does not exempt health-care organizations from doing their own due diligence. Nevertheless, their experience and lessons learned can serve as valuable resources to health-care organizations as they enter this space.
For health personnel who are burned out by the still-unfolding COVID-19 pandemic, marshaling the emotional reserves to address another crisis is a tall order. Mitigating climate change has always been seen as tomorrow's problem, and leadership at many health organizations may continue to regard it as such. Unfortunately, just as delaying treatment results in worse outcomes, putting off climate change mitigation risks significant harm in the near-term.
Although all organizations have a stake in addressing climate change, the health sector has a unique mandate. Climate change could reverse hard-earned- health gains. For health organizations that do make ambitious net zero commitments, short-term sacrifices may be offset by longer term gains as sustainability requirements become standardized across industries. In both health and climate action, an ounce of prevention is worth a pound of cure.