Asian Air Pollution Fueling Stronger Pacific Storms

COLLEGE STATION, Texas, March 6, 2007 (ENS) - Increasing levels of air pollution from Asia are affecting global weather patterns by intensifying clouds and storms over the Pacific Ocean, according to new research published Monday. The findings are more worrying news for the Arctic, which the authors of the research contend will warm more quickly due to the stronger Pacific storms.

The study shows a "direct link" from large-scale storm systems to pollution from human activities, said lead author Renyi Zhang, an atmospheric scientist at Texas A&M University.

Increased coal burning in Asia, notably China and India, over the past two decades has pumped massive amounts of pollution into the atmosphere, dramatically boosted the concentration of tiny pollution particles, notably soot and sulfur dioxide, over the region.

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The study warns of the link between pollution and stronger Pacific storms. (Photo courtesy NASA)

Sulfur dioxide emissions alone have increased 35 percent over the past decade, the researchers report in this week's edition of the Proceedings of the National Academy of Sciences.

The local impacts of this pollution have long been recognized, and many Chinese and Indian cities continue to struggle with the impacts of poor air quality.

But these tiny particles of pollution, known as aerosols, do more than cause smog, the researchers report, and their increase has coincided with a rise in the deep convection clouds that comprise many Pacific storms.

Aerosols affect the size of water droplets and change the dynamics of the clouds themselves, Zhang explained. More aerosols means smaller water droplets, which in turn leads to larger deep convection clouds and stronger storms.

Zhang's research team analyzed satellite imagery and computer modeling and found the amount of deep convection clouds over the North Pacific between 1994-2005 increased 20 to 50 percent over the preceding decade.

The researchers added that the intensified Pacific storm track "likely has profound implication on climate."

The problem is especially worse during the winter months, the researchers said, noting that various climate conditions cause the northern Pacific Ocean is more susceptible to the aerosol effect in winter.

The Pacific storm track also plays a role in global atmospheric circulation, carrying polluted particles to the west coasts of Canada and the United States, across America and eventually, most of the world. It also tends to transport heat and moisture to the world's northern latitudes.

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Scientists are just beginning to understand the global ramifications of increasing air pollution - here a thick layer of smog and smoke hangs over China on July 11, 2002. (Photo courtesy NASA)

"The Pacific storm track can impact weather all over the globe," Zhang said. "The general air flow is from west to east, but there is also some serious concern that the polar regions could be affected by this pollution. That could have potentially catastrophic results."

The concern comes from the belief that this pollution, particularly soot, can settle on Arctic ice, causing it to absorb more heat from the sun. This could accelerate melting, Zhang said, who added that the pollution from storm tracks could also signify stark changes in weather patterns.

"You might have more storms, and these storms might be more severe than usual," he said. "Or it could lead to the opposite - severe droughts in other areas. 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."