Cleaner air has increased the number of city heatwaves

image via New Scientist

July 22, 2025, 6:00 PM

• •Reducing air pollution improves public health but accelerates heatwaves.
• •Aerosols, from fossil fuels, cool the planet, masking greenhouse gas warming.
• •Cleaning air pollution, while good for health, intensifies heatwaves.
• •Heatwave frequency is amplified in populated areas due to aerosol reduction.
• •Future scenarios predict significant increases in heatwave days.

Efforts to reduce air pollution, crucial for public health, inadvertently worsen climate change impacts. Aerosol pollution, mainly from burning fossil fuels, has masked a significant portion of greenhouse gas warming by reflecting sunlight, creating a cooling effect. However, as air pollution declines, particularly in populated areas, the warming effects of greenhouse gases become more apparent, leading to more frequent and intense heatwaves. Projections indicate a dramatic increase in heatwave days, especially in densely populated regions, necessitating major operational changes.

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