Cleaner Air Accelerates Global Warming
Declining sulphate aerosol pollution is removing a cooling effect that had partly masked greenhouse gas warming.
Updated on Oct. 31, 2026 in Environmental
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Falling sulphur emissions from clean-air policies in Europe, North America, and China have reduced sulphate particles that reflect sunlight, and research accounting for natural climate variation finds the underlying global warming rate has accelerated. The Met Office projects that 2027 is very likely to surpass 2024 as the warmest year on record.
Why it matters
Sulphur reductions were pursued to protect human health and prevent acid rain, but they also lessen the cooling influence of sulphate particles. Scientists note that this shift means the warming trend is steeper than it would otherwise appear.
Research accounting for natural climate variation estimates that declining aerosol pollution adds about 0.05 to 0.1 degrees Celsius of warming per decade, against roughly 0.2 degrees Celsius per decade from greenhouse gases. The precise combined contribution of the two effects over longer periods has not been detailed in the source material.
The players
Met Office
The United Kingdom's national weather service, which provides climate and weather forecasting and monitoring for the country and beyond.
The details
Fossil fuel combustion releases sulphur dioxide, which forms particles that brighten clouds and reflect sunlight, and this cooling effect has diminished as emissions fell. The effect of declining aerosols is more pronounced in western-central Europe, though carbon dioxide, which traps heat for centuries, remains the dominant driver of climate change.
Timeline
Over past decades: clean-air policies reduced sulphur emissions in Europe, North America, and China.
In recent years: research found the underlying global warming rate has accelerated.
2027: the Met Office projects it will very likely surpass 2024 as the warmest year on record.
The Big Picture
The sulphur reductions enacted under Europe, North American, and Chinese clean-air policies, originally aimed at health and acid rain, have removed a cooling offset that scientists had not fully weighed. This reframes the policy record as one where aerosol cooling was quietly suppressing the greenhouse-gas signal.
Because warming is accelerating, the years ahead are likely to set new records, and policymakers weighing emissions and air-quality rules will need to account for the reduced cooling from aerosol decline. Reducing carbon dioxide remains the central lever for limiting long-term temperature rise.
The takeaway
Cleaner air brings real health benefits, but it also removes a cooling effect that was masking part of the warming trend. Cutting carbon dioxide emissions remains the key to slowing long-term climate change.
Further reading
Explore more on how air pollution policy intersects with the climate system in our Environmental coverage.
Source note: This article includes information reported by RocketNews.
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