China's desertification is growing worse. (Environmental Intelligence).

The world's most populous country is losing ground, literally, in its long-running battle to save farmland from drying up and turning to dust. The problem is not new, but recent signs indicate that attempts to stem the loss may actually be making it worse. In November 2002, NASA's Terra satellite observed an enormous dust storm moving over northeastern China toward the Korean peninsula and the Pacific. It was a replay of a dust cloud that blew off China a year earlier and carried enough mass to briefly darken the sky over North America. Giant dust storms have become recurring signs of an ongoing stripping of soil from land that has been overgrazed or eroded, as well as from the Gobi Desert and other arid regions of the country.

Desertification evidently has been eroding China's agricultural base for millennia, according to researchers from the Chinese Academy of Science, the University of Western Australia, and the University of Arizona, who recently published a finding that human activities have expanded the desert in northern China southward by 300 kilometers over the past 3,000 years. In the past 50 years, desertification has accelerated, as the country's growing population has intensified the demand for crop productivity and led to a depletion of soil and irrigation water on marginal land. The amount of land available for food production per capita dropped by half between 1950 and 1990, and since then-despite concerted government efforts to stem the encroachment-the problem has defied solution.

In the 1990s, the Chinese government began requiring that land used for urban expansion be replaced by new land for agriculture, but the result was a tilling of increasingly marginal land, the thin soil of which quickly dried up and blew away. While China is about the same size as the United States, it has only one-eighth as much good farmland-and three times as many people. Ironically, one consequence of the failing efforts to use marginal land is that large numbers of poor farmers have abandoned the land to the winds and joined the country's huge internal migration to the cities-further exacerbating the cities' competition with agriculture for both land and water.

The most visible sign of this unsustainable erosion of the Chinese resource base is the dust. According to the Chinese Meteorological Agency, there were 23 major dust storms in the 1990s-a great increase over their frequency in earlier decades.