Governments faced with food shortages at home have been slapping on export restrictions. Export taxes in Argentina have so angered farmers that they have gone on strike. We know that populations are rising and the availability of fertile land is falling. China, already a major food importer, faces so many environmental disasters that it will be forced to accelerate foreign food purchases. Chinese companies are scouting for agricultural land in South America and Africa to grow soyabeans, edible oils, vegetables, bananas and other food crops for export back to China, where food prices in the first quarter of 2008 were 25% higher than a year earlier.

Much of China’s farmland is suffering from water stress, soil erosion and pollution. The water situation is especially dire.  Over the North China Plain, for example, vital for wheat production, irrigation water from about 3.6 million wells is draining the aquifers below. Measurements in the early 2000s, now out of date, revealed that the water table was nearly 300 feet below ground level. In 2008, the water table is probably 370 feet down.

Several rivers flow above the surrounding land, because of the eroded soils that rains wash into them, causing the river beds to silt up. The Yellow River (Huang He) flows higher and higher above the plain, creating enormous flood dangers.

China’s answer to environmental disasters is to throw technology at them, which can amplify problems instead of solving them. The Three Gorges Dam is one, a barrier behind which 275 miles of the Yangtze river will be contained. The floor of the dam will silt up in time, and the water will become polluted.  Water from the Yangtze is being diverted in a new canal, the South-North Water Transfer Project, going all the way to the North China Plain, to compensate for the falling water table. The canal includes a tunnel under the Yellow River, in a venture costing tens of billions of dollars that may be completed by 2012, although the extent of water pollution threatens the whole rationale of this mega scheme.

Even if the canal succeeds in bringing some usable water to the farmland of the north, China is going to need more and more food but has decreasing capability to produce it. Rising competition for food means soaring prices and shortages. It means that the British policy of relying on world markets to buy in the net 40% of food that is not home-produced is outdated, short-sighted and irresponsible.