Adapted from the release released by the International Climate Research Center.
In a new study in the journal East Asia Communications Earth and the Environment found that air pollution cleaning in East Asia has accelerated global warming. That’s because some form of air pollution in the atmosphere helps to free the surface of the earth from the sun’s energy.
Global warming rates, driven primarily by greenhouse gas emissions, have been accelerating over the past 15 years and have resulted in record surface temperatures.
During the same period, countries in East Asia, especially China, implemented active air quality policies, resulting in approximately 75% of sulfur dioxide (SO₂) emissions. These policies are important public health victories: In China, for example, ambient air pollution kills more than one million people each year.
But as countries get better at reducing air pollution, they have also inadvertently exposed global warming.
“Many aerosol particles emitted from human activities reflect incoming sunlight and have a surface cooling effect,” Westervelt said. “As their concentrations in the atmosphere decrease, our study shows that it can play a major role in recent warming.”
The team used climate modeling to isolate the role of reducing aerosols in recent temperature trends.
“Over the past 15 years, we have been able to pinpoint the climate impacts of East Asian air quality policy,” said Bjørn H. Samset, chief writer and senior researcher at Cicero International Climate Research Center. “Our main result is that East Asian aerosol cleaning may have driven much of the recent global warming acceleration and the warming trends in the Pacific.”
Analyzing the climate impacts of emissions from individual regions is challenging. It requires climate simulations that are not yet readily available and emission data are updated to capture the actual pollution reduction in mainland China and around it. Using a large number of simulations from eight different climate models, the researchers showed how 75% reduction in East Asian sulfate emissions partially revealed greenhouse gas-driven warming and altered how temperatures rise around the world.
The study also explores how long the warming effect of aerosol reduction is expected to last.
“The climate impact of air pollution is short-lived, and the effects of carbon dioxide emissions have been done for centuries,” said Laura Wilcox, associate professor at the National Center for Atmospheric Sciences at the University of Reading. “This means that the acceleration of warming due to the reduction of air pollution may also be short-lived. In the event of disclosure, we will see an acceleration of warming, and then restore the greenhouse gas-driven warming as air pollution stabilizes.”
Other Colombian co-authors from the Centre for Climate Systems Research include climate scientists Kostas Tsigaridis and Larissa Nazarenko.
News interviews with Daniel Westervelt and other authors can be arranged by emailing [email protected].
