Beijing on a clear day. Pexels
A new study finds a drop in air pollution likely drove a recent surge in warming.
Warming has accelerated over the last two decades, and in particular, over the last two years. Scientists say that shifting cloud cover, changes in solar activity, and even a volcanic eruption may be factors. But according to a new study, the biggest driver is the cleanup of air pollution in East Asia, primarily in China.
Over the last 15 years, Chinese officials have cracked down on sulfur dioxide seeping from power plants and factories. The pollutant can cause wheezing, coughing, and shortness of breath, but it also reacts with other airborne compounds to form sulfates, tiny particles that block sunlight, with a cooling effect.
The recent drop in industrial pollution led to a surge in warming, according to the modeling study, published in Nature Communications Earth and Environment.
Chinese sulfur dioxide emissions in tons. Sulfur dioxide reacts with other compounds to form sunlight-blocking sulfates. Source: Community Emissions Data System. Our World in Data
Prior research had linked the drop in sulfates to a rise in ocean warming in the Pacific. The new study is the first to link the pollution cleanup to a global surge in warming going back more than 10 years. A 75 percent decline in sulfates in East Asia “has likely driven much of the recent global warming acceleration,” said lead author Bjørn H. Samset of the CICERO Centre for International Climate Research in Norway.
Researchers described the drop in pollution as an “unmasking” that revealed the true extent of warming. “We will see an acceleration of warming while the unmasking takes place,” said coauthor Laura Wilcox of the University of Reading in the U.K. But, she said, an “acceleration in warming due to reductions in air pollution is also likely to be short-lived.”
