Restricting Aerosol Pollution May Worsen Impacts of Climate Change

by Vins

Federal government efforts to reduce aerosol pollutants, including the US Clean Air Act, have led to what climate scientist James Hansen has described as a “Faustian bargain,” Jake Bittle reported for Grist in February 2024. On one hand, these regulations aim to protect people from the negative health effects of aerosol pollution—including asthma, heart disease, and cancer; on the other hand, aerosol emissions have actually helped offset some of the negative consequences of climate change. Without aerosol emissions, Bittle reported, the world might have already warmed by another half a degree Celsius, because aerosols have a cooling effect that counteracts greenhouse gas emissions.

“If you remove aerosols from the air, you reduce the health impacts of pollution, saving thousands of people from lung and heart disease, but you might also make global warming worse,” Bittle wrote, citing Hansen’s assessment and findings from recent regulations on big container ships.

A decrease in aerosol emissions might intensify hurricane seasons by enabling large storms to retain additional moisture. A research report published in Nature Communications in February 2024 found that aerosols influence flooding patterns, with the presence of aerosols suppressing the impact of climate change on rainfall, thus delaying the expected surge in flood risks. The findings pose a dilemma:  If air pollution declines in the United States over the next few decades, many more Americans in regions such as the Southeast could see severe flooding and dangerous storms.

As of March 28, 2024, the concerns raised by Jake Bittle’s report for Grist have not been widely covered by the establishment press, likely due in part to the complexity of the science and the dilemma it poses. The differing effects of aerosols on human health and the global climate have not been received the attention they deserve. This gap in coverage limits the abilities of policymakers and citizens to advocate for balanced, scientifically-informed approaches to regulation.

Source: Jake Bittle, “How Air Pollution Delayed a Surge in Extreme Rain,” Grist, February 22, 2024.

Student Researchers: Abigail Hamill, John Simonetti, and Natasha Tykulsky (University of Massachusetts Amherst)

Faculty Evaluator: Allison Butler (University of Massachusetts Amherst)