We’ve reported heavily on the severe drought in California and on the devastating effects of water shortages in other areas of the world. Those situations are frightening enough on their own, but this week, two new studies led by University of California at Irvine (UCI) researchers using NASA data shows that the entire world’s water supply is truly in danger. More than half of the world’s aquifers are being depleted.

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NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite system is responsible for monitoring the world’s water supply, and it works by measuring dips and bumps in Earth’s gravity, which are caused by the amount of water underground. This is the same system that, earlier this year, put California’s remaining water supply at one year.

The new studies (here and here) illustrate 10 years of data, from 2003 to 2013, and the picture is not pretty. 13 of the world’s 37 major aquifers, located in places like China, India, France and even the United States, are being depleted with little or no replenishment. Another 8 aquifers classify as “overstressed” because their supplies are being used at a rate faster than nature can refill them.

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The most alarming aspect of this news is that the amount of groundwater remaining is pretty much unknown. It simply cannot be measured accurately with satellite technology. “Given how quickly we are consuming the world’s groundwater reserves,” said UCI professor and principal investigator Jay Famiglietti, who is also the senior water scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, “we need a coordinated global effort to determine how much is left.”

Alexandra Richey, the study’s lead author who conducted the research as a UCI doctoral student, backed up that claim, saying, “In a water-scarce society, we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”

Via NASA

Images via NASA and UC Irvine/NASA/JPL-Caltech