Healthcare’s Hidden Carbon Footprint: OECD Links 80% of Emissions to Supply Chains

The OECD’s first cross-country study finds that healthcare generates 4.4% of greenhouse gas emissions in its member states, with nearly 80% arising from global supply chains rather than hospitals themselves. The report warns that decarbonising health requires international cooperation, tackling pharmaceuticals, energy, transport, and manufacturing alongside reforms within clinics and hospitals.

The Organisation for Economic Co-operation and Development (OECD), through its Directorate for Employment, Labour and Social Affairs and its Directorate for Science, Technology and Innovation, has issued a groundbreaking working paper authored by Cédric Doucet, Michel Lioussis, Norihiko Yamano and Michael Mueller. For the first time, it quantifies greenhouse gas emissions generated by health systems across OECD countries. Using the Inter-Country Input-Output (ICIO) tables alongside the Joint Health Accounts Questionnaire (JHAQ) expenditure database, the study provides unprecedented insight into the climate burden of modern healthcare. Long regarded as a sector devoted solely to saving lives, health is revealed here as both a victim of climate change and a contributor to it, with wide-ranging implications for policy and practice.

The Numbers Behind the Footprint

According to the report, healthcare across the OECD produced over 960 million tonnes of greenhouse gases in 2018, the equivalent of an average 520 kilograms of CO₂-equivalent per person. On average, this accounted for 4.4 per cent of all demand-based emissions in OECD economies. Yet the averages mask dramatic variation: the United States, with its vast and energy-intensive healthcare sector, recorded the highest per capita emissions at 1,400 kilograms, while Colombia and Costa Rica registered only about 100 kilograms. This fifteen-fold disparity is explained by differences in health spending levels, energy intensity, and the reliance of national power grids on fossil fuels. The data also signals a long-term challenge. Although per capita emissions have remained relatively stable since the early 2000s, the ageing of populations and the growing use of high-tech medical interventions threaten to increase the sector’s footprint in the future.

Hospitals, Medicines, and Nursing Homes

Breaking the figures down reveals which areas of healthcare drive the most emissions. Hospitals, outpatient care providers, and medical goods, particularly pharmaceuticals and devices, together account for nearly three-quarters of the carbon burden. In Korea and Croatia, hospitals are the single largest contributor, responsible for about 40 per cent of healthcare emissions, while in Luxembourg and Germany, their share is closer to 20 per cent. By contrast, pharmaceuticals and medical goods dominate in Slovakia and Bulgaria, making up more than 40 per cent of the total. Nursing homes are another hotspot, particularly in the Netherlands, where they contribute roughly one-fifth of healthcare-related emissions. The study notes limitations in current modelling, which assumes that hospitals, outpatient clinics, and nursing homes share the same emission intensity, but even with such caveats, the overall picture is clear: the key drivers of healthcare emissions lie in a handful of subsectors that touch millions of patients every day.

Supply Chains: The Invisible Majority

Perhaps the most striking conclusion of the report is that the majority of healthcare’s emissions occur not inside hospitals but throughout their sprawling supply chains. Only 12 per cent of emissions come directly from facilities through fuel use, and another nine per cent from purchased electricity. The remaining 79 per cent fall into Scope 3 emissions: the indirect footprint of the energy, materials, and services used to keep health systems running. Electricity, gas, and steam production alone make up 30 per cent of health-related emissions, while pharmaceuticals and chemicals contribute nine per cent, other manufacturing 17 per cent, transport 12 per cent, and agriculture and mining 14 per cent. This finding reframes the conversation about climate-friendly healthcare. Retrofitting hospitals and switching to renewable energy remain necessary steps, but they address only a fraction of the challenge. The bulk of emissions is embedded in supply chains, from the power required to produce drugs to the agricultural products that supply hospitals with food.

Global Supply Chains, Shared Responsibility

Another major insight is that half of all healthcare emissions in OECD countries are generated outside national borders. In small, import-dependent economies such as Luxembourg, Austria, and Switzerland, more than 70 per cent of emissions originate abroad, largely due to reliance on imported pharmaceuticals and equipment. In contrast, countries with large domestic industries like the United States, Mexico, and Poland see about 70 per cent of their healthcare emissions generated at home, reflecting both industrial capacity and reliance on carbon-heavy energy. This globalisation of healthcare complicates policy responses: no single country can fully address the problem alone. International cooperation and supply-chain decarbonisation are indispensable if the sector is to meaningfully reduce its footprint.

A Call for Climate-Smart Healthcare

The OECD’s analysis is consistent with previous studies by Pichler and colleagues, Health Care Without Harm, and Lenzen et al., which estimate healthcare’s share of emissions between 3.8 and 5.5 per cent. But by combining ICIO and JHAQ data, the OECD provides a uniquely comparable international baseline. The policy implications are direct: while national initiatives to decarbonise hospitals and clinics are valuable, they cannot address the overwhelming share of emissions generated by supply chains. The report suggests that ministries of health must work hand-in-hand with energy, industry, agriculture, and transport sectors. Future improvements to the model could include capturing staff and patient travel, tracking emissions along care pathways, and expanding indicators beyond greenhouse gases to cover water, land, and waste footprints.

The OECD report is both a warning and an opportunity. It warns that without action, healthcare will continue to contribute significantly to climate change even as it struggles with the health impacts of rising temperatures, extreme weather, and shifting disease patterns. Yet it also identifies an opportunity: every step towards a lower-carbon health system delivers twin benefits, cutting emissions while protecting populations from climate-driven illness. By putting numbers to the problem, this first-of-its-kind analysis provides the foundation for a new era of climate-smart healthcare policy, where sustainability is not an afterthought but an integral part of safeguarding human life.