Scientists say one-third of the Earth's major aquifers, which give water to 2billion people, are stressed by human use 

  • Thirteen of 37 major aquifers placed in a troubled category by new study from University of California, Irvine and NASA 
  • The groundwater most in danger, which sees no replenishment for water taken by humans, are in Middle East and India
  • California's Central Valley Aquifer, currently being taxed by extra demand because of drought, said to be 'highly stressed'
  • Study used new method that measured gravitational pull on satellites to detect how much water was being lost 
By Christopher Brennan For Dailymail.com
Published: 23:40 EST, 16 June 2015 | Updated: 23:51 EST, 16 June 2015
More than half of the world's largest basins of groundwater are being stressed by human use, a new study says.
Twenty-one of Earth's 37 biggest aquifers, which give water to 2billion people, are 'past sustainability tipping points' and lost more water than they gained over a decade, according to research from scientists at the University of California, Irvine.
Roughly a third of the groundwater reservoirs were 'stressed' throughout the world, including the United States, though the most stressed were found in densely populated regions that have become political hot spots.
Scientists say that one-third of the world's 37 biggest aquifers are stressed by use from humans, and more than half lost water than they received between 2003 and 2013 (pictured) . Above, aquifers labelled in dark red saw the most depletion while aquifers in light and dark blue saw the least
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Scientists say that one-third of the world's 37 biggest aquifers are stressed by use from humans, and more than half lost water than they received between 2003 and 2013 (pictured) . Above, aquifers labelled in dark red saw the most depletion while aquifers in light and dark blue saw the least
Though the most stressed aquifers are in particularly dry, densely populated areas of the world such as the Middle East and India, the Central Valley Aquifer in California (pictured) was also said to be 'highly stressed'
'The water table is dropping all over the world,' researcher Jay Famiglietti said. Above, a farmer checks salt from dried up irrigation water in Stockton, California
Though the most stressed aquifers are in particularly dry, densely populated areas of the world such as the Middle East and India, the Central Valley Aquifer in California (pictured) was also said to be 'highly stressed'
Eight of the 21 were said to be overstressed or highly stressed, meaning the aquifers, often in very dry areas, have no water filling them back up as humans use what remains. 
The Arabian Aquifer System above Iraq and Saudi Arabia and the Indus Basin in south Asia topped the list of reservoirs seen their waters supply dwindle.  
'The water table is dropping all over the world,' NASA and Irvine's Jay Famiglietti, the principal investigator of the studies, told the Washington Post. 'There's not an infinite supply of water.'
Researchers used NASA's Gravity and Recovery and Climate Experiment satellites to find out how much water the aquifers were losing, in addition to collecting data about how much was used for agriculture, mining and humans. 
Scientist Jay Famigliette (pictured) and scientists from UC Irvine used data from the gravitational pull on satellites to measure how water was being use
Researchers say that previous studies, which did not use satellite data, may have drastically overestimated the amount of water humans have left. Above, a graphic of NASA's GRACE satellite system
Researcher Jay Famigliette (left) and scientists from UC Irvine used data from the gravitational pull on satellites to measure how water was being used. Above right, a graphic of NASA's Grace satellite system
The study from Famiglietti and other scientists was unsure if some aquifers have thousands of years or decades of water left. Above, the Indus Basin in Pakistan (pictured) is the second-most stressed
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The study from Famiglietti and other scientists was unsure if some aquifers have thousands of years or decades of water left. Above, the Indus Basin in Pakistan (pictured) is the second-most stressed
The GRACE satellites were able to measure slight changes in the gravitational pull on them that was extrapolated to detect how much water was beneath the Earth's surface at particular points on the globe. 
Work done by Famiglietti and others forWater Resources Research suspected that previous estimates for the amount of the important resource left in some aquifers, done without satellite data, were inflated by 'orders of magnitude'.
He said that we are unsure if some of the most stressed aquifers have thousands of years left of water or maybe only decades. 
Though California (16) and the Gulf Coast (18) have stressed aquifers, the Northern Great Plains Aquifer (14), Ogallala Aquifer (17) and Cambrian-Ordovician aquifer system in the upper Midwest all gained water
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Though California (16) and the Gulf Coast (18) have stressed aquifers, the Northern Great Plains Aquifer (14), Ogallala Aquifer (17) and Cambrian-Ordovician aquifer system in the upper Midwest all gained water
The most stressed aquifer system was below Middle Eastern countries such as Saudi Arabia (pictured), where the groundwater supports 60million people
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The most stressed aquifer system was below Middle Eastern countries such as Saudi Arabia (pictured), where the groundwater supports 60million people
The scientists say that increased population growth, food demand and climate change may also cause increased use of aquifers as surface water becomes less available.
Aquifers have already begun being tapped to make up for droughts in places such as California.
More than 60 per cent of the state's water this year is coming from groundwater sources such as the state's Central Valley Aquifer System. 
That aquifer system was also considered highly stressed. 
Though three groundwater systems in the middle of the US are not yet stressed by human use, the Atlantic and Gulf Coastal Plains aquifer under Florida and the Gulf Coast is also stressed. 
The GRACE data was collected between 2003 and 2013.