Lester Brown, author of Who Will Feed China?, attempts to answer his own question in an op-ed in the Washington Post:

The evidence of China’s plight is clear. Since 1950, some 24,000 villages in the northwestern part of the country have been totally or partially abandoned as sand dunes encroach on cropland. And with millions of Chinese farmers drilling wells to expand their harvests, water tables are falling under much of the North China Plain, which produces half of the nation’s wheat and a third of its corn.

Chinese agriculture is also losing irrigation water to cities and factories. Cropland is being sacrificed for residential and industrial construction, including highways and parking lots that accommodate China’s voracious demand for automobiles. In 2009, automobile sales in China totaled just under 14 million, surpassing those in the United States for the first time. For every 1 million cars added to this fleet, at least 50,000 acres are paved over.

And China’s food supply is already tightening. In November, its food price index was up 12 percent from 2009. The price of vegetables alone was up 62 percent.

In these conditions, how do you feed more than 1 billion people? This question vexes China’s leaders, many of whom are survivors of the Great Famine, in which 30 million people starved to death between 1959 and 1961. Last year, in an effort to halt rising food prices, the government auctioned corn, wheat, rice and soybeans from state reserves. And in recent years, China has bought or leased land in other countries from Sudan to Indonesia to produce food and biofuels, but there is little to show in production from these lands so far.

If China, which imported about 2 million tons of U.S. corn and wheat combined in 2010, charges into the U.S. grain market, American consumers will find themselves competing with nearly 1.4 billion foreign consumers for the U.S. grain harvest. This would raise the prices not only of products made directly from grain, such as bread, pasta and breakfast cereals, but also of meat, milk and eggs, which take large quantities of grain to produce. Corn futures have already hit $7 a bushel, up from $2 a bushel five years ago. In that same period, soybean futures climbed from $6 a bushel to $14 a bushel, and cattle and hog futures hit all-time highs.