Two new studies show that the world’s population is consuming groundwater at a rapid pace even without knowing when it might run out. Satellite data revealed that a third of the world’s largest groundwater basins are in extreme distress. However, it is difficult to say how much water still remains in them. Findings of both the studies were published in the journal Water Resources Research.

Groundwater Depletion

Arabian Aquifer System the most overstressed groundwater source

Jay Famiglietti, a senior water scientist at NASA and professor at the University of California-Irvine, said that civilization is consuming groundwater reserves at an alarming rate. Now we need a “coordinated global effort” to determine how much water is left. Famiglietti said the available chemical and physical measurements were insufficient.

Researchers used data from NASA’s twin GRACE satellites that measure bumps and dips in the Earth’s gravity. The weight of water affects our planet’s gravity. For the first study, they analyzed 37 of the world’s largest groundwater reserves between 2003 and 2013. The eight worst off aquifers had no natural replenishment to offset usage, so they were classified as “overstressed.”

Five others were “extremely or highly stressed,” depending on the level of replenishment. It means they are still stressed, but some water is flowing back into them. Scientists said that the Arabian Aquifer System, which provides water to over 60 million people, is the world’s most overstressed groundwater source. The Indus basin of northwestern India and Pakistan came second.

The situation would only worsen

Scientists warned that things are only going to get worse with population growth and climate change. California’s Central Valley aquifer was labeled as “highly stressed.” The second study, done by the same team, concluded that the total volume of remaining usable groundwater in the world is poorly known. Famiglietti said it is far less than rudimentary estimates made a few decades ago.

The most stressed aquifers are found in the world’s driest parts, where there is little or no natural replenishment. Alexandra Richey, the lead author of both studies, said, “What happens when a highly stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?”