Earth got a bit of a fever in 2020, in part because of cleaner air from the pandemic, a new study finds.
For a short time, temperatures in some places in the eastern United States, Russia and China were as much as half to two thirds of a degree (0.3 to 0.37 degrees Celsius) warmer. That’s because of fewer soot and sulfate particles from car exhaust and burning coal, which normally cool the atmosphere temporarily by reflecting the sun’s heat, Tuesday’s study in the journal Geophysical Research Letters. reported.
Overall, the planet was about 0.05 degrees (0.03 degrees Celsius) warmer for the year because the air had fewer cooling aerosols, which is unlike carbon dioxide pollution you can see, the study found.
“Cleaning up the air can actually heat the planet because that (soot and sulfate) pollution leads to cooling,” as climate scientists have long known, said lead author Andrew Gettelman, an atmospheric scientist at the National Center for Atmospheric Research. His calculations come from comparing the weather in 2020 with computer models that simulated a 2020 without the reduction of pollution from pandemic lockdowns.
This temporary warming effect of fewer particles was stronger in 2020 than the effect of reduced heat-trapping carbon dioxide emissions, Gettelman said. That’s because carbon stays in the atmosphere for over a century with long-term effects, while aerosols stay in the air for about a week.
Even without the reduction in cooling aerosols, global temperatures in 2020 were already flirting with breaking the annual heat record due to the combustion of coal, oil and natural gas – and the aerosol effect may have been enough to make this the hottest year in NASA’s measurements. . systemsaid NASA’s top climate scientist Gavin Schmidt, who was not part of this study, but said it confirms other research.
“Clean air warms the planet just a little bit, but it kills a lot less people with air pollution,” said Gettelman.
___
Follow Seth Borenstein on Twitter: @borenbears
___
The Associated Press Department of Health and Science is supported by the Science Education Department of the Howard Hughes Medical Institute. The AP is solely responsible for all content.