by Patrick Morency
“Groundwater depletion the world over poses a far greater threat to global water security than is currently acknowledged.” Nature Publishing Group, Nature.com
An alarming satellite-based analysis from NASA, released last month, finds that the world is depleting groundwater — the water stored underground in soil and aquifers — at an unprecedented rate. This is doubly concerning in our age of virtually unrestricted carbon pollution. Drops in precipitation and soil moisture due to climate change will increase reliance on groundwater, sharply boosting the chances of civilization-threatening mega-droughts and dust storms reminiscent of the 1930s Dust Bowl. California’s Sacramento and San Joaquin river basins have already lost roughly 15 km3 of total water per year since 2011 — more water than all 38 million Californians use for domestic and municipal supplies annually — over half of which is due to groundwater pumping in the Central Valley.
The world is perilously ignoring the water crisis that is occurring underfoot, writes Jay Famiglietti, leading hydrologist at the NASA Jet Propulsion Laboratory, in the journal Nature Climate Change. “Vanishing groundwater will translate into major declines in agricultural productivity and energy production, with the potential for skyrocketing food prices and profound economic and political ramifications,” he claims. Water treaties between countries that share a river basin are common, Famiglietti notes, but treaties to define and divide groundwater resources are rare. The United Nations say that 448 aquifers cross political boundaries – a number that continues to rise as more studies are completed. The consequences of inaction are stark, Famiglietti asserts.
The highest rates of groundwater depletion are in the world’s largest food-growing regions: California’s Central Valley, the Ogallala Aquifer of the American Great Plains, the plains of Northern China and Northwest India, as well as the Tigris and Euphrates River Basin. Further declines in groundwater availability may well trigger more civil uprising and international violent conflict in the already water-stressed regions of the world, and new conflict in others. As reserves fall, society will find responding to droughts and shifting weather patterns all the more difficult. It is now up to the politicians and managers to heed the warnings.