As the severe drought in California continues for a third straight year, water levels in the State’s lakes and reservoirs is reaching historic lows.
Two new studies offer worrying results, showing that human activity is responsible for about one third of Earth’s largest underground water reserves being rapidly drained. Researchers have no idea how much there will be left in the end.
Massive portions of the planet’s population tap into the groundwater resource without being aware of how much water there still is. The research will be published in the journal Water Resources Research, but the findings can already be found online.
Leading investigator Jay Famiglietti, professor at the University of California Irvine, explained that it’s not enough to use the current chemical and physical measurements; in order to estimate how fast are the world’s groundwater reserves draining, an international effort needs to be conducted.
Famiglietti also works as a senior water scientist in NASA’s Jet Propulsion Laboratory, so his team had access to data provided by special NASA satellites in their endeavor of accurately measuring groundwater losses.
For the first study, researchers looked at data on Earth’s top 37 aquifers – the largest ones we have – between 2003 and 2013. They noticed that 8 of these are in the category of “overstressed,” which means they are almost dry with little to no possibility of being naturally replenished in order to balance out the extreme usage.
In addition, 5 other aquifers were classified as “extremely or highly stressed.” Scientists concluded that climate change and population growth are two factors that are putting a lot of strain on these reserves.
It is obvious that the most overburdened aquifers are located in the hottest and driest areas on Earth, where natural in the world’s driest places, where natural refilling is almost never an option.
Lead author on both researches, Alexandra Richey tries to warn concerned authorities about the future dramatic situations where highly stressed aquifers located in regions with socioeconomic tensions won’t be enough to sustain life in the area.
For this to be prevented, Richey works to raise red flags that would geolocate regions where active initiatives and water-supply management could result in a better future for coming generations.
The world’s most overstressed source of water is the Arabian Aquifer System, which will soon become dry as it provides water for a population larger than 60 million individuals. On second and third place are the Indus Basin aquifer of Pakistan and northwestern India, and the Murzuk-Djado Basin in northern Africa, respectively.
One that hits closer to home is the Central Valley aquifer, located in drought-stricken California; this one has already been marked as “highly stressed.”
Problem is, scientists have no idea how much water is there left in the world’s usable resources, and time before they dry out is a highly variable estimation. Some scientists believe we have some decades until complete depletion, while others think in terms of millennia.
Image Source: CBS News