Hydrologist Scott Jasechko of the University of California, Santa Barbara, is one of those authors. He was part of a team that analyzed water-level data stretching back to 1980. Those data came from some 170,000 monitored water wells. They offer a glimpse of the status of nearly 1,700 natural stores of groundwater — among the world’s largest.
From those wells, the team now shows where water has been disappearing fastest. In 12 percent of these aquifers, water levels are now dropping by more than half a meter (1.6 feet) per year. And more than one in three of these aquifers have shown water levels dropping by a tenth of a meter (4 inches) per year.
Declines were fastest in some of the world’s driest regions. These included central Chile, Iran and the U.S. West.
There are signs of hope
In some places, though, large groundwater stores have begun to grow — even after shrinking at the end of the last century. Such changes likely come from managing these aquifers differently, the study suggests.
Take an aquifer in Thailand’s Bangkok basin. Its groundwater losses have reversed in the last 20 years. Why? Governments around it began charging fees for using groundwater. They also started licensing wells.
