Sydney, Jan 11: Water supplies will begin running out in critical regions where they support cities, industries and food production including in India, China and the Middle East by 2030 due to over-extraction of groundwater, a scientist has warned.

"The world has experienced a boom in groundwater use, more than doubling the rate of extraction between 1960 and 2000 -- with usage continuing to soar up to the present," says Craig Simmons, director of the National Centre for Groundwater Research and Training (NCGRT).

A recent satellite study has revealed falling groundwater tables in the US, India, China, Middle East and North Africa, where expanding agriculture and cities have increased water demand.

"Groundwater currently makes up about 97 percent of all the available fresh water on the planet and presently accounts for about 40 percent of our total water supply," says Simmons, also a member of Unesco's global groundwater governance programme, according to a NCGRT statement.

"Not many people think of groundwater as a key driver of the global economy -- yet it is. If it becomes depleted, entire industries may be forced to shut down or move. Whole regions could face acute water scarcity."

"Over-extraction also has serious implications for the environment, especially when the climate is warming -- as falling water tables can lead to emptying lakes and rivers and dying landscapes as the water they depended on is withdrawn," Simmons says.

In the Middle East, depleted aquifers have been a major driver of the relocation of agriculture to Africa and the so-called 'land grab' by wealthy countries. 

Even advanced nations such as the United States face a crisis in their use of groundwater, says Robert Glennon, law professor at the University of Arizona.

"Groundwater now comprises one-quarter of the US supply and more than half of all Americans rely on groundwater for drinking. Unconstrained drilling of new wells, as many as 800,000 per year, has put incredible strain on aquifers around the US," he says.