Is Asian air pollution changing US weather patterns?

Monday 07th Sep 2015 by theWeather Club

Research published in the Proceedings of the National Academy of Sciences suggests that air pollution from China and other Asian countries is having far-reaching impacts in weather patterns across the Northern Hemisphere.

Parts of Asia have some of the highest levels of air pollution, with some cities frequently exceeding levels recommended by the World Health Organisation. Tiny particles - produced from the burning of coal in power plants or traffic emissions, for example - can hitch-hike on the jet stream and are blown towards the north Pacific. Water vapour in the atmosphere condenses around these particles (known as ‘cloud condensation nuclei’), with large amounts of particulate matter producing larger, deeper clouds that can cause intense storms above the ocean. 

This study – conducted by researchers from NASA’s Jet Propulsion Laboratory – used computer models to look at the effect of Asia’s air pollution on weather systems, finding that the pollutants are strengthening storms above the Pacific Ocean, which subsequently feeds into weather systems in other parts of the world, particulary in winter.

Lead author Dr Yuan Wang, from the Jet Propulsion Laboratory at the California Institute of Technology, said: “The effects are quite dramatic. The pollution results in thicker and taller clouds and heavier precipitation.”

“Since the Pacific storm track is an important component in the global general circulation, the impacts of Asian pollution on the storm track tend to affect the weather patterns of other parts of the world during the wintertime, especially a downstream region [of the track] like North America.”

Commenting on the study, Professor Ellie Highwood, a climate physicist at the University of Reading (and tWC contributor – p.13), said: “We are becoming increasingly aware that pollution in the atmosphere can have an impact both locally - wherever it is sitting over regions - and it can have a remote impact in other parts of the world. This is a good example of that.”

“There have also been suggestions that aerosols over the North Atlantic effect storms over the North Atlantic, and that aerosols in the monsoon region over South Asia can affect circulation around the whole of the world.”