Smokestacks at the Dearborn Industrial Generation facility in Dearborn, MI.Jim West / ZUMA
This story was originally published by Grist and is reproduced here as part of the Climate Desk collaboration.
The past half-century has seen remarkable improvements in air quality in many parts of the world, thanks largely to legislation like the Clean Air Act. Efforts like these took aim at pollutants like the group of chemicals known as aerosols, which include sulfur dioxide, nitrogen dioxide, and other compounds that are harmful to human health.
Like greenhouse gases, aerosols are produced by cars, factories, and power plants—but unlike greenhouse gases, they make the earth cooler rather than warmer. This is because aerosols reflect the sun’s rays, rather than trapping its heat like carbon. Some studies estimate that, without aerosol pollution, the world might have already warmed by another half a degree Celsius.
This creates a tricky paradox, which renowned climate scientist James Hansen has called a “Faustian bargain.” 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. This powerful relationship has been on display over the past few years in the maritime shipping industry: As freight ships have stopped using dirty bunker fuel since 2020, they’ve also stopped emitting trails of sulfur dioxide, which has caused world temperatures to jump by an additional .05 degrees C.
Now, new research shows that the interaction between aerosols and greenhouse gases also has implications for flooding, which is one of the........