Emerging threatsWorld running out of fresh water: NASA data
Two new studies using data from NASA Gravity Recovery and Climate Experiment (GRACE) satellites show that human consumption is rapidly draining some of the world’s largest groundwater basins, yet there is little to no accurate data about how much water remains in them. This means that the world’s largest underground aquifers, on which hundreds of millions of people rely for fresh water, are being depleted at an accelerated rate – a rate of depletion which has pushed these aquifers beyond their sustainability tipping points: During the 10-year study period, more water was removed than replaced.
Two new studies led by UC Irvine using data from NASA Gravity Recovery and Climate Experiment (GRACE) satellites show that human consumption is rapidly draining some of the world’s largest groundwater basins, yet there is little to no accurate data about how much water remains in them. This means that the world’s largest underground aquifers, on which hundreds of millions of people rely for fresh water, are being depleted at an accelerated rate – a rate of depletion which has pushed these aquifers beyond their sustainability tipping points: During the 10-year study period, more water was removed than replaced.
The result is that significant segments of Earth’s population are consuming groundwater quickly without knowing when it might run out, the researchers conclude. The findings appeared yesterday in Water Resources Research.
“Available physical and chemical measurements are simply insufficient,” said UCI professor and principal investigator Jay Famiglietti, who is also the senior water scientist at NASA’s Jet Propulsion Laboratory. “Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left.”
A UCI release reports that the studies are the first to characterize groundwater losses via data from space, using readings generated by NASA’s twin GRACE satellites that measure dips and bumps in Earth’s gravity, which is affected by the weight of water.
For the first paper, researchers examined the planet’s thirty-seven largest aquifers between 2003 and 2013. The eight worst off were classified as overstressed, with nearly no natural replenishment to offset usage. Another five aquifers were found, in descending order, to be extremely or highly stressed, depending upon the level of replenishment in each — still in trouble but with some water flowing back into them.
The most overburdened are in the world’s driest areas, which draw heavily on underground water. Climate change and population growth are expected to intensify the problem.
Global warming has caused the regions closest to the equator to become drier and more extreme latitudes to experience wetter and heavier rains, launching a self-reinforcing cycle. People living in mid-range latitudes pump more water from aquifers to contend with drier conditions, and that water, once removed from the ground, then also evaporates and gets recirculated to areas far north and south.
