Tens of millions of these wells have been drilled over the past decade, many of them beyond any official control, and powerful electric pumps are being used to haul up the water at a rate that far outstrips replenishment by rainfall, the British weekly says in next Saturday's issue.

The extraction is providing many countries with a lavish harvest in thirsty crops like rice, sugar cane and alfalfa, but the boom is bound to be shortlived, it says.

Indeed, water tables are falling so dramatically that within a short time, some landscapes could become arid or even be transformed into desert, it says, quoting scientists at a worldwide water conference.

In the case of India, smallholder farmers have driven 21 million tube wells into their fields and the number is increasing by a million wells per year.

"Nobody knows where the tube wells are or who owns them. There is no way anyone can control what happens to them," Tushaar Shah, head of the International Water Management Institute's groundwater station, based in tGujarat, said.

"When the balloon bursts, untold anarchy will be the lot of rural India."

Half of the country's traditional hand-dug wells have already run dry, as have millions of shallower tube wells, causing some despairing farmers to commit suicide, he said.

In China's north plain, that country's breadbasket, 30 cubic kilometers (1.059 trillion cubic feet) more water are being extracted each year by farmers than are being replaced by the rain, New Scientist said.

Groundwater is used to produce 40 percent of the country's grain.

In June, the state paper China Daily admitted that the nation "may be plunged into a water crisis" by 2030 when its population is scheduled to peak at 1.6 billion.

The tube-well revolution, whose technology is adapted from the oil industry, has also swept water-stressed countries like Pakistan and Vietnam, where precious underground reserves are likewise being depleted, New Scientist says.

"Vietnam has quadrupled its number of tube wells in the past decade to one million, and water tables are plunging in the Pakistani state of Punjab, which produces 90 percent of the country's food."

The scientists spoke at the Stockholm Water Symposium, a conference held in the Swedish capital last week.

TERRA.WIRE