This prospect is resulting in sleepless nights in Beijing, worry about rising grain prices in grain importing countries, and a deepening concern in the U.S. intelligence community about its effect on political stability in these countries.

Drawing on recent information from China and a newly unveiled report from the National Intelligence Council (NIC), Brown and co-author Brian Halweil will discuss the challenge now facing the Chinese government: how to meet the needs of fast-growing cities and industry without shortchanging agriculture to the point where rising grain imports destabilize world grain markets.

The debate over China's food outlook picked up steam after the publication in 1995 of Brown's book,Who Will Feed China?, which marshaled the existing evidence for the growing water shortages in China.

Initially denounced by the Chinese government, the book stimulated an on-going reassessment of the issue in China and abroad. The National Intelligence Council in Washington, D.C., the umbrella organization over all U.S. intelligence agencies, has just weighed in with its own exhaustive study. Using information not publicly available, it confirms the Worldwatch Institute's earlier projections.

Brown, who will be addressing an official agricultural forum on this issue in Beijing in late May, notes, "Because China's potential demand is so large, it cannot import the grain it needs without driving world grain prices up, leaving the 1.3 billion of the world's people who subsist on $1 a day at risk.

The goal for China is to be as self-sufficient in food as possible by fashioning an internal solution to the problem of water scarcity."

China's farmers now face strong competition for water from cities and industry. Of China's 617 cities, 300 are facing water shortages. In many, these shortfalls can be filled only by diverting water from agriculture.

For China, solving its water problems means more than simply adopting more water efficient technologies. "The Chinese must restructure their entire economy to make it more water efficient," said Brown.

Even with an all-out effort to build a water-efficient economy, irrigation water losses and a steep rise in grain imports seem inevitable. The NIC study, which modeled China's key river basins, concluded that in the most likely scenario, China will be importing 175 million tons of grain by 2025.

But total world grain exports, after tripling between 1960 and 1980, have leveled off at around 200 million tons-and thus may not be able to satisfy this additional need.

Worldwatch Institute: www.worldwatch.org