Big drain on groundwater
Overuse of freshwater supplies poses risks
2012 SCIENCE NEWS TOP 25: 24
Everyone needs fresh water, but sometimes need trumps wise use. Humankind’s thirst is draining many aquifers faster than they can be replenished, with some disastrous effects. A new global map of nations’ varying “groundwater footprints” showed the world’s water supplies being sucked up, much of them used to water crops (SN: 9/8/12, p. 10). By the study’s measure, India, Pakistan and Saudi Arabia are among the thirstiest countries.
The possibility of running out of water isn’t the only threat. Pumping groundwater, whether for irrigation or drinking, turns out to contribute more to global sea level rise than scientists had thought (SN Online: 5/21/12). Taking water out of the ground means it eventually runs off into the sea. Many scientists had assumed that the water added from aquifers would be roughly balanced by the amount impounded behind dams, but two studies conclude that that’s not the case.
Finally, groundwater extraction can literally kill people. Geologists found this year that pumping aquifers shifted the stresses on faults in southeastern Spain. The scientists concluded after the fact that a magnitude 5.1 quake that killed nine people in the region in May 2011 had happened earlier than it otherwise would have because of water being drained out of the ground (SN: 12/1/12, p. 13).