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Science Notebook

Sunday, February 20, 2005; Page A21

A sampling of noteworthy presentations yesterday at the annual meeting of the American Association for the Advancement of Science, taking place in Washington this weekend.

Global Warming Could Block Cleansing Summer Winds

Global warming could stifle cleansing summer winds across parts of the northern United States over the next 50 years and worsen air pollution, researchers said yesterday.

Further warming of the atmosphere, as is happening now, would block cold fronts bringing cooler, cleaner air from Canada and allow stagnant air and ozone pollution to build up over cities in the Northeast and Midwest, they said.

"The air just cooks," said Loretta Mickley of Harvard University's Division of Engineering and Applied Sciences. "The pollution accumulates, accumulates, accumulates, until a cold front comes in and the winds sweep it away."

Mickley and colleagues used a computer model, an approach commonly used by climate scientists to predict weather and climate changes. She said that the model predicted a 20 percent decline in summer cold fronts out of Canada.

"If this model is correct, global warming would cause an increase in difficult days for those affected by ozone pollution, such as people suffering with respiratory illnesses like asthma and those doing physical labor or exercising outdoors," she said.

World temperatures have risen by an average of 1 degree Fahrenheit over the past century.

-- Reuters

Water Restores Iraq Marshes; Birds and Wildlife Returning

Wetlands that once sheltered Marsh Arabs and a host of wildlife in southern Iraq are being partly restored and could offer a haven once again if the restoration is done right, experts said yesterday.

Water coming into the area from the Tigris and Euphrates rivers is unexpectedly clean, washing away toxic salts that built up when the area was drained under Saddam Hussein's rule, the international team of experts reported.

Bird species, including pelicans, cormorants and wading birds, are starting to return. The area was also important for spawning fish and shrimp, but with only 20 percent of the marshes restored, these animals have a long way to go, the experts said.

"The future of the 5,000-year-old Marsh Arab culture and the economic stability of large portions of southern Iraq are dependent on the success of this restoration effort," they write in next week's issue of the journal Science.

There would be political benefits as well. "I think you could stabilize huge, vast areas of Iraq by doing this," said Curtis Richardson, an ecologist at Duke University said at the meeting.

Hussein drained more than 90 percent of the 5,800 square miles of marshes during his rule, in part to punish the Shiite Marsh Arabs who opposed him, in part to provide access to the border with Iran during the 1980s war and in part to save water for cities upstream.

Richardson said after Hussein was ousted, farmers blew up dikes and earthen dams that had held the water back.

-- Reuters

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