A Third of World’s Major Aquifers Rapidly Depleting: Report
Posted by feww on June 18, 2015
Groundwater basins likely far smaller than previously thought: Researchers
Some of the world’s largest groundwater basins are rapidly depleting due to excessive human consumption, according to two new studies led by UC Irvine.
Researchers say they they don’t know exactly how much more water remains in the basins.
The findings are significant because humans are consuming groundwater quickly without knowing when it might run out, the researchers say.
“Available physical and chemical measurements are simply insufficient,” said UCI principal researcher. “Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left.”
Researchers classified eight of the planet’s 37 largest aquifers as “overstressed,” with almost “no natural replenishment to offset usage,” and five others as “extremely or highly stressed.”
Unsurprisingly, the most stressed aquifers are in the world’s driest areas, which depend greatly on underground water. “Climate change and population growth are expected to intensify the problem.”
“What happens when a highly stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?” asks the lead author on both studies. “We’re trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods.”
Researchers found that the Arabian Aquifer System, on which more than 60 million people depend, is the most overstressed reserve in the world.
The second-most overstressed reserve is the Indus Basin aquifer in NW India and Pakistan, with the Murzuk-Djado Basin in northern Africa in third position. California’s Central Valley is also classified as “highly stressed.”
“As we’re seeing in California right now, we rely much more heavily on groundwater during drought,” said the principal researcher.
“We don’t actually know how much is stored in each of these aquifers.” The lead author said. “In a water-scarce society, we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”
[Globally, about 2.2 billion people rely on groundwater as the primary source of freshwater. Estimate is based on FIRE-EARTH Models.]
The report is posted at Water Resources Research