From an editorial in Sunday’s Washington Post:
When rivers, streams and reservoirs are low, as they are in California, people start digging holes. Large, unseen pools of water are trapped in the spongy rock and soil of the world’s aquifers, sometimes fairly close to the surface, sometimes deep underground. Tapped groundwater can save communities from economic or humanitarian catastrophe. But in too many places, humans are depleting this crucial reserve, just as climate change begins taking its toll.
A NASA study released this last week provides authoritative estimates of the state of 37 major aquifers around the globe. Using satellites that measured minor variations in the earth’s gravitational pull between 2003 and 2013, researchers found that 21 of these aquifers are being run down.
According to J.S. Famiglietti, the author of the NASA study, the first thing to do is establish the size of groundwater reserves, in a process akin to estimating subterranean oil reserves, so that people know how much is left. From there should come effective monitoring of groundwater use, pinpointing who’s taking how much and for what purpose. This information will make it easier to identify opportunities to use water more efficiently.
Many people didn’t need satellites to know that aquifers are in trouble. They are drilling deeper and deeper for groundwater. The poor can’t afford to construct ever-deeper wells, so they will be out of the game in stressed areas. Governments cannot ignore this issue for long.