Anyone who shivered, shoveled, and slogged their way through last winter is probably eager to find someone or something to blame for the chill of so many months. The polar vortex and its frequent, unwelcome southern excursions into the U.S. was the favored villain of this winter, with some climate scientists warning that a warming world may make this phenomenon more frequent.
Now, new research suggests that soaring Asian air pollution may be responsible, at least in part, for weird weather close to home.
Scientists say pollution from China and other heavily coal dependent booming Asian economies is strengthening storms above the Pacific Ocean, causing more precipitation, and pushing heat from the tropics toward the North Pole at an impressive clip. Last winter, the Arctic heated up while the cold flowed down into Canada and the Eastern United States. The Pacific storm track, as it’s known, has a huge impact on global circulation patterns especially in “downstream” areas like North America.
“There appears to be little doubt that these particles from Asia affect storms sweeping across the Pacific and subsequently the weather patterns in North America and the rest of the world,” said Dr. Renyi Zhang one of the paper’s co-authors and Director at the Center for Atmospheric Chemistry and the Environment at Texas A&M; University, in a press release.
Lead author Yuan Wang, an atmospheric scientist at NASA’s Jet Propulsion Laboratory, told LiveScience that pollution-driven cyclones and high-pressure systems in the northern Pacific may have influenced the swoops in the jet stream that brought cold air down from the North Pole.
The research, conducted by a team of scientists — several from Texas A&M; University — was published on Monday in the current issue of Proceedings of the National Academy of Sciences.
Naturally, there are lots of aerosols — small particles suspended in the air over the Pacific thanks to dust and sea salt. Aerosols play many different roles in the atmosphere. They can both scatter and absorb sunlight, with both cooling and warming affects. When water vapor condenses around aerosol particles, a cloud is formed. Farmers desperate for rain often intentionally “seed” clouds, but it appears that coal-fired power plants and vehicle emissions in Asia are inadvertently creating the perfect conditions for enormous storm systems to form.
The researchers used pollution emission data compiled by the Intergovernmental Panel on Climate Change and advanced global climate models to compare “pre-Industrial” and “present-day” air pollution rates. They found that an increase in man-made aerosols is probably causing stronger cyclones in the Pacific and generally intensifying the Pacific storm track. The warm air moves up into the tropics, and the cold air moves south, contributing to the colder-than-average winter in much of the U.S.
“The climate model is quite clear on this point. The aerosols formed by human activities from fast-growing Asian economies do impact storm formation and global air circulation downstream,” said Dr. Zhang. “They tend to make storms deeper and stronger and more intense, and these storms also have more precipitation in them. We believe this is the first time that a study has provided such a global perspective.”
While there is some debate over whether China or India has the dirtiest air, both Beijing and Delhi somewhat routinely experience smog that soars past what the World Health Organization considers hazardous for human health.