In two new studies, a team of researchers led by hydrologists from the University of California, Irvine assessed the depletion of groundwater on a global scale using readings from NASA satellites. They also concluded that although there is little solid information about how much water remains in aquifers, it’s likely much less than previously estimated, leaving big unanswered questions about how soon those reserves of groundwater might run out.
“If we continue to use groundwater the way it’s being used, then there’s a high chance that it could be depleted to the point that we can no longer use it in my lifetime in certain areas,” said Alexandra Richey, the lead author of the studies.
Richey said she was surprised to learn that rudimentary and widely varying estimates, in some cases dating back to the 1960s and 1970s, are often the only available guesses of how much groundwater remains in aquifers. She said that lack of hard data makes it crucial for there to be a major effort to explore aquifers and quantify the amounts of water that remain underground.
“There’s no way we can keep using these aquifers at the rates that we are without understanding what some of the tipping points are,” Richey said in a telephone interview.