Smog in India, China is changing weather patterns in US, finds study

Man-made air pollution kills millions of people every year, but a new study suggests that poor air quality in India and China could be contributing to extreme weather patterns in the U.S. and Canada.

The study by researchers at Texas A&M, the first of its kind to focus on smog in Asia, found that air pollution originating in the region almost certainly affects global weather patterns.

How much of an effect, researchers say, remains to be seen. However, it is likely exacerbating problems already caused by climate change: increasing the intensity and frequency of storms, ice cap melting, sea level rise, and drought.

Scientists have already determined that carbon emissions, or greenhouse gases, contribute to climate change. But the smog in Asia is caused by more than just the burning of fossil fuels — it's comprised of nitrogen oxides, methane and other volatile organic compounds that combine to produce ozone. 

Scientists used satellite imagery and computer models to show that man-made air pollution created in Asia is adversely affecting the Pacific Ocean storm track, which transports weather westward from Asia to the west coasts of Canada and the U.S.

The pollution is causing an increase in the formation of deep convective clouds, from 20 to 50 percent. The result is more extreme storms, according to the study funded by NASA and the National Science Foundation.

“This pollution directly affects our weather,” Renyi Zhang, professor of atmospheric sciences at Texas A&M and lead author of the study, said in a statement.

“During the past few decades, there has been a dramatic increase in atmospheric aerosols — mostly sulfate and soot from coal burning — especially in China and India,” he said. 

Both China and India have experienced widespread economic growth in recent years. Large, dirty factories and power plants, combined with the effects of wood and coal burning stoves among large populations have meant that the countries are now among the world's largest contributors of man-made air pollution.

Those toxins ride the Pacific storm track to the west coasts of Canada and the U.S., across North America, and eventually over most of the world, impacting clouds in their wake, the study found. That could lead to increased frequency and intensity of storms or even severe droughts.

What’s more, soot particles in the form of black carbon can collect on ice packs in the poles — which attract more heat from the sun and accelerates ice-cap melting.

Melting ice caps results in the release of methane, which exacerbates global warming, and also contributes to accelerated sea level rise.

Sea level rise already poses an existential threat to residents of low-lying areas around the world.

“The Pacific storm track plays a crucial role in our weather, and there is no doubt at all that human activity is changing the world’s weather,” Zhang said.