The Healthcare Sector’s Carbon Footprint: How Hospitals Became a Climate Problem
Photo by Jeremy Bishop on Unsplash
If the global healthcare sector were a country, it would be the fifth-largest greenhouse gas emitter on the planet. That is not a metaphor. It is a measured, documented fact — and it demands a response from within the profession.
The previous article in this series established what a green hospital is and what it does for patients. This article asks the prior question: how did hospitals become part of the climate problem in the first place, and how large is the problem actually?
The answer is larger than most people in the profession realise. Health care’s climate footprint is equivalent to between 4.4 and 5 per cent of global net emissions — approximately 2 gigatons of carbon dioxide equivalent per year. To put that in terms that hold the scale: it equals the annual greenhouse gas output of 514 coal-fired power plants, or the exhaust of more than 75 million cars running continuously for a year. [1]
This is not a sector on the margins of the climate crisis. It is a significant contributor to it. Understanding where those emissions come from is the first step toward doing something about them.
Where Healthcare’s Emissions Come From
Healthcare emissions divide into three categories, each with a distinct origin and a distinct set of reduction strategies. [2][3]
Direct emissions — 17% of the total
These are the emissions produced on-site: fossil fuel combustion in heating systems and boilers, hospital vehicle fleets, and — a category that surprises most clinicians — anaesthetic gases. Several commonly used anaesthetic agents, particularly desflurane, are potent greenhouse gases with a global warming potential hundreds of times greater than carbon dioxide. They escape into the atmosphere during use and are not recovered. This is one of the areas where individual clinical practice has a direct and measurable impact on a hospital’s carbon footprint.
Indirect emissions — 12% of the total
These arise from purchased energy: electricity, steam, cooling, and heating drawn from external sources. The hospital does not burn the fuel directly, but its demand drives the emissions. This category is where the transition to renewable electricity has its most immediate impact — a hospital that switches to a clean energy supply eliminates this 12 per cent at a stroke.
Supply chain emissions — 71% of the total
This is the number that consistently surprises people, including those who work in hospital management. Nearly three-quarters of healthcare’s entire global emissions footprint lies not in the building or the vehicles, but upstream and downstream in the supply chain: the manufacturing, transport, and disposal of pharmaceuticals, medical devices, single-use equipment, food, and hospital consumables. [1][2]
The manufacturing of pharmaceuticals and medical devices is energy-intensive and heavily reliant on petrochemical inputs. Single-use plastics — gloves, drapes, packaging, syringes — are produced from fossil fuels and disposed of, in most cases, by incineration or landfill. Food procurement for hospital catering carries its own agricultural and transport emissions. The supply chain is where the largest reduction opportunity lies, and it is also where hospitals have historically had the least visibility and the least leverage.
One further figure worth holding: roughly one-quarter of all healthcare emissions are generated outside the country where the healthcare product is ultimately consumed. This is a global supply chain problem as much as a domestic one. [1]
The Highest-Emission Departments
Not all parts of a hospital contribute equally to its carbon footprint. The emission load is concentrated in a small number of operational areas. [3]
Facility operations
Heating, cooling, and powering a hospital around the clock is the baseline energy load. Unlike commercial buildings, hospitals cannot be switched off at night or on weekends. The continuous demand for lighting, climate control, and powered medical equipment means that facility operations represent a large fixed emission source that is present regardless of patient volume.
The operating room
Operating rooms are three to six times more energy-intensive than the rest of the hospital. Two factors drive this: the very high air-exchange rates required for infection control — which means the air-handling system is working at maximum capacity continuously — and the use of volatile anaesthetic gases, which are both clinically necessary and, in many cases, among the most potent greenhouse gases in routine use anywhere in the economy.
Procurement and supply chain
As the 71 per cent figure above makes clear, the purchasing decisions of hospital procurement departments are the single largest driver of the institution’s carbon footprint. Up to 80 per cent of a hospital’s total emissions footprint lies in the lifecycle of the medical products, devices, and pharmaceuticals it buys. This means that procurement policy is, in a meaningful sense, climate policy.
Waste management
Hospitals generate thousands of tonnes of medical waste daily, with single-use plastics representing the dominant volume. The disposal of this waste — primarily through incineration — produces its own direct emissions, as well as the embedded emissions of the materials themselves.
Beyond Carbon Dioxide: The Full Range of Healthcare Greenhouse Gases
Healthcare’s emissions are not limited to carbon dioxide from energy use and transport. The sector produces a range of greenhouse gases, several of which carry a warming potential far in excess of CO₂. [3]
Methane (CH₄)
Generated during the decomposition of organic waste in landfills and from some energy generation processes. Hospitals that dispose of food waste and organic material through conventional landfill are contributing to methane emissions they rarely measure.
Nitrous oxide (N₂O)
A potent greenhouse gas that arises from waste incineration and the production of specific medical chemicals. Nitrous oxide is also, of course, a widely used anaesthetic agent — one of the oldest in clinical use — and its atmospheric warming potential is approximately 265 times that of carbon dioxide over a 100-year period.
Fluorinated gases
Hydrofluorocarbons (HFCs) and related compounds are released from refrigeration systems and from certain medical equipment, including pressurised metered-dose inhalers and some anaesthetic delivery systems. These gases have extremely high global warming potentials and long atmospheric lifetimes. The transition away from HFC-based inhalers toward dry-powder alternatives is one of the single most impactful individual-level clinical decisions available to prescribing doctors.
What Hospitals Are Doing About It
The scale of the problem is daunting. The solutions, at least at the level of institutional strategy, are reasonably well established. What they require is not new technology but institutional commitment and procurement discipline. [4]
Energy transition
Upgrading to high-efficiency building infrastructure and transitioning to 100 per cent renewable electricity sources is the most direct route to eliminating the 12 per cent indirect emissions category and significantly reducing the 17 per cent direct emissions category. Several health systems have committed to net-zero energy targets with fixed deadlines.
Greener anaesthetics
Transitioning away from desflurane — which has a global warming potential approximately 2,500 times that of carbon dioxide — toward less climate-damaging alternatives such as sevoflurane, regional anaesthesia, or total intravenous anaesthesia (TIVA) is among the highest-impact individual clinical decisions available. This is a change that requires no new infrastructure, only a shift in prescribing practice.
Supply chain reform
Requiring vendors and pharmaceutical companies to report and reduce their own carbon footprints, and building sustainability criteria into procurement frameworks, begins to address the 71 per cent supply chain problem. This is slow work, but it is where the largest long-term impact lies.
Waste reduction
Shifting from disposable, single-use surgical and medical tools to reusable alternatives wherever safety permits reduces both the embedded emissions of manufactured goods and the direct emissions from their disposal. The infection control argument against reusables is legitimate in a narrow set of applications. In a much larger set, single-use practice is a habit rather than a clinical requirement.
Conclusion
The healthcare sector’s carbon footprint is not a peripheral concern for administrators with time to spare. It is a systemic problem embedded in the energy infrastructure, the supply chain, the procurement habits, and the clinical practices of every hospital operating today. The 4.4 to 5 per cent global figure matters because it is large enough to be meaningful in climate terms, and because the sector that generates it has both the professional standing and the institutional capacity to lead a credible response.
The good news is that the emission sources are well mapped and the reduction strategies are established. The operating room anaesthetic gas switch, the move to renewable energy, the reusable equipment programme, the supply chain emissions requirement — none of these requires waiting for a technological breakthrough. They require a decision.
The next article in this series moves from the problem to the first of the building-block solutions: energy efficiency in hospitals, and what solar power, smart HVAC, and LED systems actually deliver in practice.
References
1. Malik A, Lenzen M, McAlister S, McGain F. The carbon footprint of Australian health care. Lancet Planet Health. 2018;2(1):e27–e35.
2. Hovland Consulting LLC, Health Care Without Harm, with Natural Resources Defense Council. Global Climate Impact from Hospital Cooling. Kigali Cooling Efficiency Program, San Francisco; 2018.
3. Sustainable Development Unit (NHS). Carbon Footprint Update for NHS in England 2012. Sustainable Development Unit, Cambridge; 2013.
4. Sustainable Development Unit (NHS). Carbon Footprint from Anaesthetic Gas Use. Sustainable Development Unit, Cambridge; 2013.
Doctor Dialogues | July 2026 | All rights reserved