Monday, June 22, 2015

ENVIRONMENT - World's Fresh Water Supply

"Is the world’s fresh water supply running out?" PBS NewsHour 6/17/2015


SUMMARY:  Recent studies have found that humans are using up water at a faster rate than it is being replenished.  Judy Woodruff talks to James S. Famiglietti, a professor of Earth system science and civil and environmental engineering at the University of California, Irvine, about what this dwindling supply of freshwater means, and whether we should be concerned about it.

JUDY WOODRUFF (NewsHour):  Hundreds of millions of people around the world depend on the use of underground rock formations known as aquifers to get the clean water they need.  But a pair of new studies show many of the largest aquifers are being depleted at alarming rates.

As seen on this map, of the 37 largest ones in the world, 21 are losing more water than is being replaced, with those areas in orange and red showing much more serious problems with depletion.  These are located in countries like China, Russia and Australia, as well as India, where water resources are already a major problem.

The reports also identify declining levels for California’s Central Valley Aquifer.

Jay Famiglietti is a lead author on one of the reports from NASA’s Jet Propulsion Laboratory. And he joins me now.

Welcome, Mr. Famiglietti.

Remind us, what is an aquifer, and how does it produce the clean water?

JAY FAMIGLIETTI, NASA Jet Propulsion Laboratory:  An aquifer is an underground soil or rock unit that contains — contains water in its pore spaces, and the way we get at that water is by drilling wells and pumping it up from the subsurface.

JUDY WOODRUFF:  So, what did these two studies find?

JAY FAMIGLIETTI:  We found that in the 37 world’s largest aquifers that we looked at, that over 21 of them are past sustainability tipping points, meaning that the rate of withdrawal exceeds the rate of replenishment.  And of those, we found that 13 are in a pretty bad way and threatened to exceed a point at which they may not come back.

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