Climate change is one of the biggest challenges for present and future generations. It is linked to many different types of environmental distress, including air pollution, rising temperatures and extreme weather events. Across OECD countries, climate change is already affecting population health and well-being, and will increasingly put pressure on health systems in the years ahead. Air pollution represents a major cause of death and disability. Projections have estimated that outdoor air pollution may cause between 6 million and 9 million premature deaths a year worldwide by 2060, and may cost 1% of global GDP as a result of sick days, medical bills and reduced agricultural output (OECD, 2015[1]).
On average across OECD countries, populations were exposed to 11.2 microgrammes of fine particulate matter (PM2.5) per cubic metre in 2020 (Figure 4.25). Only one country – Finland – had average levels of PM2.5 pollution below the WHO air quality guidelines target of 5 microgrammes per cubic metre in 2020. Exposure to ambient outdoor particulate matter pollution declined between 2010 and 2020 in most OECD countries, by an average of 24%, although it increased in three OECD countries over this period (Australia, Chile and Japan). While policies to reduce pollution have led to some important reductions in deaths caused by air pollution in many OECD countries, exposure to ambient particulate matter remains a major environmental and public health concern: it was responsible for an estimated 4.1 million premature deaths in 2019, globally (GBD, 2019[2]).
In addition to the consequences of climate change for health outcomes, health systems themselves play an important role in greenhouse gas (GHG) emissions. New OECD analysis suggests that in 2018, healthcare‑related emissions in OECD countries represented 4.4% of overall GHG emissions across the entire economy on average, amounting to more than 960 million tonnes of carbon dioxide‑equivalent (CO2‑e) emissions (Figure 4.26). On average across OECD countries on a per capita basis, 523 kilogrammes of CO2 -e emissions were related to healthcare in 2018. This average masks a 15‑fold variation across countries: from 1 430 kilogrammes of CO2‑e emissions in the United States to 95 kilogrammes in Colombia.
Across the OECD and beyond, countries are increasingly recognising the role the health sector can play in reducing its environmental footprint, including its GHG emissions (OECD, 2025[3]). Transforming healthcare delivery to reduce GHG emissions – such as by promoting policies that reduce low-value care – could help to drive down GHG emissions while also helping to reduce waste in the system. National and cross-country initiatives to decarbonise supply chains and introduce green procurement standards for healthcare products and services are emerging.
