Scientists have struggled to explain the rapid acceleration of global warming over the past 15 years, with temperatures now regularly breaking records. It’s “among the biggest questions in climate science today,” said atmospheric professors Laura Wilcox and Bjørn H. Samset at The Conversation.
Suggested causes include a cleanup of sulphur emissions from global shipping, as well as changes in cloud cover. But “one factor that has not been well quantified” is the “monumental efforts” by East Asian countries, particularly China, to combat air pollution, the researchers said. East Asia’s “aerosol cleanup” is likely a “key reason” for the temperature surge, as the polluted air “may have been masking the full effects of global warming,” according to a recent study by Wilcox and Samset.
“In the early 2000s, China had extremely poor air quality as a result of rapid industrialization, leading to a public outcry in the runup to the 2008 Beijing Olympics,” said New Scientist. The government began concerted and highly effective efforts to reduce air pollution, but there’s a “sting in the tail of this environmental success story” — China’s dirty air had “inadvertently been cooling the planet.”
Reducing air pollution didn’t actually cause additional warming, but it “removed an artificial cooling” effect, said Wilcox and Samset at The Conversation. Air pollution “shields the Earth from sunlight,” said Wilcox. The aerosol particles also reflect sunlight into space or influence cloud formation so that they reflect more sunlight. Reducing air pollution means removing “this artificial sunshade,” she said. And since greenhouse gas emissions (the main driver of global warming) have continued to increase, the Earth’s surface is “warming faster than ever before.” |