India, China polluting US weather: study

Pollution from China and India is affecting the weather in America, especially the west coast, a recent study has said.

"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," explains Professor Renyi Zhang, lead author of the study conducted by Texas A&M University researchers.

Both countries have seen huge increases in their economies, which mean more large factories and power plants to sustain such growth.

All of these emit immense quantities of pollution -- much of it soot and sulfate aerosols -- into the atmosphere, which is carried by the prevailing winds over the Pacific Ocean and eventually worldwide, the researchers reported in the Proceedings of the National Academy of Sciences.

"This pollution directly affects our weather," explained Zhang.

The study is the first large-scale analysis to draw a link between Asian air pollution and the changing Pacific weather patterns.

"The pollution transported from Asia makes storms stronger and deeper and more energetic," said Zhang, who is professor of atmospheric sciences.

"It is a direct link from large-scale storm systems to (human-produced) pollution."

Satellite imagery and computer models revealed that in roughly the last 20 years or so, the amount of deep convective clouds in this area increased from 20 to 50 per cent, suggesting an intensified storm track in the Pacific.

"We compared these deep convective clouds from the 10-year period of 1984-1994 to the period from 1994-2005 and discovered these storms have risen anywhere from 20 to as high as 50 per cent."

Zhang said the problem is especially worse during the winter months. Because of various climate conditions, the northern Pacific Ocean is more susceptible to the aerosol effect in winter. Aerosols can affect the droplets in clouds and can actually change the dynamics of the clouds themselves, Zhang added.

The Pacific storm track carried these polluted particles to the west coasts of Canada and the United States, across America and eventually, most of the world, Zhang noted.

"The Pacific storm track can impact weather all over the globe," he said.

The general airflow 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.

Soot, in the form of black carbon, can collect on ice packs and attract more heat from the sun, meaning a potential acceleration of melting of the polar ice caps, he said.