Scientists recently analyzed data retrieved from NASA’s GRACE (Gravity Recovery and Climate Experiment) satellite showing nearly a third of the world’s largest groundwater basins are being rapidly depleted. To add to the matter, a major problem facing scientists is the fact that we don’t exactly know how much water is left on earth either. Sounds strange given the technological advancements scientists have made over the years, but according to one of NASA’s senior water scientists, it’s a very real problem. In order to understand what sustainable water use is and isn’t, we need to know what we working with and right now the “time to depletion” ratios are extreme estimates. For example, with the Northwest Sahara Aquifer System, the “time to depletion” estimates range anywhere between 10 years and 21,000 years. That is far to unpredictable of a number to build a sustainable use framework with.
Jay Famiglietti, Senior Water Scientist at NASA’s Jet Propulsion Laboratory stated that our current measurements are not enough to go on, “Available physical and chemical measurements are simply insufficient”…”Given how quickly we are consuming the world’s groundwater reserves, we need a coordinate global effort to determine who much is left.”(1)
According to a set of studies published in Water Resources Research Journal, 13 of the 37 largest aquifers were being depleted between 2003 and 2013. Of these 13 taxed aquifers, 5 of them have been determined “seriously affected by the rate of water usage”.
The 37 largest aquifers are located throughout the world but some areas are being hit harder than others. A water source for more than 60 million people, The Arabian Aquifer System, is noted as the hardest-hit.(1) Others follow shortly behind like the Indus Basin aquifer of India and Pakistan, the Murzuk-Djado Basin in northern Africa and California’s Central Valley.(1)
Scientists are uncertain about exactly how much water is left in the worlds crucial reservoirs and one reason for this is because the aquifers are typically located far below the earths surface deep inside rock. In order to learn more about our remaining water supply, deep drilling is necessary, but it is also very expensive and difficult to do. On this, the scientist quickly followed with saying “It is crucial that we find out”.
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To Read the published report, find it here: Quantifying Renewable Groundwater Stress with GRACE
(1) Augenstein, S. (2015, June 18). One-third of Earth’s Groundwater Being Rapidly Sucked Up by Humans, NASA Says. Retrieved July 7, 2015, from http://www.laboratoryequipment.com/news/2015/06/one-third-earths-groundwater-being-rapidly-sucked-humans-nasa-says
Quantifying Renewable Groundwater Stress with GRACE
Richey, A. S., Thomas, B. F., Lo, M.-H., Reager, J. T., Famiglietti, J. S., Voss, K., Swenson, S. and Rodell, M. (2015), Quantifying renewable groundwater stress with GRACE. Water Resour. Res.. Accepted Author Manuscript. doi:10.1002/2015WR017349
Image: By NASA [Public domain], via Wikimedia Commons