for National Geographic News
Earlier this year, an unusually large dust cloud that originated in northwest China drifted across the continental United States and lingered over Denver and other areas, at times obscuring views of the Rocky Mountains.
It isn't the first time a giant dust cloud from east Asia has reached the United States. But concerned observers say the vast sweep and the density of this latest one suggests that northwest China's once-fruitful agricultural land is eroding at an alarming rate, becoming useless desert.
China has mounted various efforts to halt the increasing desertification, which is caused by overuse of the land for farming and grazing. Nonetheless, as much as 900 square miles (2,300 square kilometers) of farmland in northern Chinaan area more than twice the size of Hong Kongis blown away by the wind each year, according to a Chinese scientist quoted in a New York Times article last year.
"If they're losing that much, then there is several times that area in various stages of deterioration. Losing it and abandoning it are sort of the final stage before it becomes desert," said Lester Brown, president of the Earth Policy Institute in Washington, D.C., which recently released an environmental alert on the problem.
East-moving winds often carry soil away from China's northwest, where overplowing and overgrazing, coupled with periods of drought, has led to massive deterioration of the country's agricultural resources.
Huge dust plumes regularly travel hundreds of miles to Beijing and other cities in northeastern China. As they move over urban centers they pick up particles from industrial pollution.
The resulting dust clouds are often so thick they obscure the sun, reduce visibility, slow traffic, and close airports. Residents caulk windows with old rags to keep out the dust, and municipal crews have to clean public structures repeatedly during the dust-storm season.
The dust clouds are also a problem for China's neighbors, and North Korea, South Korea, and Japan have registered official complaints. Responding to pressure from their citizens, legislators from Japan and South Korea are organizing a tri-national committee with Chinese lawmakers to devise a strategy to combat the dust.
On March 10, 2001, The People's Daily reported that the season's first dust stormone of the earliest on recordhad hit Beijing. The recent dust storms and those of last year were said to be among the worst in memory.
The growing severity of the dust clouds has raised world concern.
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