Air pollution kills nine million people annually, mostly in low-income countries.
Climate change worsens air quality, amplifying health, ecosystem, and agricultural risks.
Methane emissions, unmonitored leaks, and long-lived greenhouse gases drive global threats.
Air pollution and climate change are creating a “vicious cycle” with negative repercussions for human health, ecosystems and agriculture, according to the Global Environment Outlook-7 (GEO-7) report published on December 9 by the UN Environment Programme (UNEP).
Climate change is worsening the effects of air pollution and waste generation, amplifying biodiversity loss, land degradation and desertification. The report warned that 99% of the world’s population is exposed to some form of air pollution and more than 90% of the nine million deaths occur in low-and middle-income countries.
1 December 2025
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According to the UNEP report, "substantial adverse health effects and related economic losses" are being caused globally by the combined pressures of warming temperatures, rising greenhouse gas emissions, improper waste management, and declining air quality.
Air pollution now affects nearly the entire global population through exposure to trace gases, plastic particles, particulate matter, heavy metals and greenhouse gases (GHG), the report noted.
Atmospheric concentrations of long-lived GHGs such as carbon dioxide and nitrous oxide, and short-lived ones like methane (CH4), ozone, and some hydrofluorocarbons are impacting the Earth’s radiative balance. Polluting particles are either emitted directly from combustion, industry, transport, fires, road and soil dust, or formed secondarily from gaseous precursors such as sulphur dioxide (SO2), nitrogen oxides, ammonia and non-methane volatile organic compounds.
Concentrations of nitrogen dioxide and sulphur dioxide increased throughout parts of Asia while levels decreased in Western Europe and North America between 2000 and 2019. Global SO2 emissions trends from 2005 to 2021 are negative, according to satellite measurements. In contrast, between 2000 and 2020, human activity-related CH4 emissions rose by about 20%, according to the report.
The report further stated that landfills and waste management facilities continue to rank among the top three global sources of methane, with emissions frequently two to three times higher than reported due to unmonitored leaks and legacy dumps.
Rising Global Risks
According to a 2022 World Health Organization (WHO) report and the Intergovernmental Panel on Climate Change, escalating heatwaves, wildfires, tropical storms and hurricanes are increasingly linked to compounded air pollution and climate impacts.
Another WHO Report published in 2023 attributed 37% of heat-related deaths to human-induced . Heat-related deaths among those over 65 have risen by 70% in two decades. In 2020, 98mn more experienced food insecurity compared to the 1981–2010 average. The WHO also projected 250 000 additional yearly deaths by the 2030s due to climate change impacts on diseases like malaria and coastal flooding. However, modelling challenges persist, especially around capturing risks like drought and migration pressures.
