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"For more than 200 days of the year this once mighty river no longer makes it to the sea. It's like the Rhine petering out in central Germany, or the Nile drying up in northern Sudan.
Why? In large part humans are to blame, in particular China's communist rulers, who have long believed nature should be bent to man's will. The river has been overused and abused. Dozens of dams block its flow, drawing off huge quantities of water to grow cotton in the desert. In 50 years the communists have done more to destroy the river than their predecessors in the last 5,000.
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Some are now predicting the creation of a dustbowl that would dwarf that of the American mid-west during the 1930s. That forced hundreds of thousands of Americans farmers off the land in a mass migration to California.
But in China the effect would be much worse. Literally tens of millions of farmers could be pushed off the land, and China has no California for them to move to. Instead they would flood in to the cities, further swelling the ranks of the unemployed and dispossessed."
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http://news.bbc.co.uk/1/hi/world/asia-pacific/3937403.stm