Pollution from China alters weather in U.S. West

A U.N. conference on climate change ended Sunday without a major deal to cut toxic emissions. No country emits more carbon dioxide than China -- a byproduct of its booming economy. And, as CBS News correspondent John Blackstone reports, those Chinese emissions are having a big impact in the U.S.

Chinese officials insist the murky air over Beijing this month is just fog. But measurements taken at the U.S. embassy there show dangerously high levels of air pollution -- so bad that traffic has been disrupted and flights have been delayed or cancelled.

"It's no longer just their problem; it's our problem," said Kim Prather of the Scripps Institution of Oceanography.

Prather studies atmospheric chemistry. CBS News met her at a scientific conference in San Francisco, where she was presenting research that shows what's in the air over China can affect the weather in America.

"The atmosphere has no walls," she said. "So pollution on this side of the world can make it the other side of the world in about five days."

The Chinese pollution is carried by the jet stream across the Pacific. In the atmosphere over this country, it can stop the clouds from producing rain and snow.

In general, Prather said, the equation is more pollution equals less precipitation.

The particles of air pollution from China collect moisture in the clouds. But the particles are so small and numerous they don't get heavy enough to fall as rain or snow. So the water stays in the clouds.

But while flying over California collecting atmospheric samples, Prather found something else from China that may make up for much of that lost rain. It's dust -- from huge storms in China's vast deserts.

Because of their chemical makeup and larger size, those dust particles do collect enough moisture to make rain and snow.

"We found that wherever there was dust, there was ice," Prather said. "And then below us was snow."

Understanding the factors that influence California's rain and snow is important because what falls in the mountains is the main water source for most of the state's 37 million people.

"We're working with the weather guys to try and see this climate-weather link with pollution," Prather said. "It's a complex problem."

By unraveling those complexities, Prather's research could improve the accuracy of weather forecasting -- explaining why some clouds just blow over while others produce snow storms.

  • John Blackstone

    From his base in San Francisco, CBS News correspondent John Blackstone covers breaking stories throughout the West. That often means he is on the scene of wildfires, earthquakes, floods, hurricanes and rumbling volcanoes. He also reports on the high-tech industry in Silicon Valley and on social and economic trends that frequently begin in the West.

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