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  • From: <pbunch@cox.net>
  • To: Healthy soil and sustainable growing <livingontheland@lists.ibiblio.org>
  • Subject: Re: [Livingontheland] Groundwater Depletion Raises Likelihood of Global Food Crises
  • Date: Thu, 30 Sep 2010 5:28:08 -0700

This is just one of the issues resulting form unsustainable use of resources.
Getting this under control is the worlds number one priority. The most
reasonable approach I have seen is the steady state economy model.
http://steadystate.org/ It is an integrated means of address multiple
problems addresses them at the economic level.

---- Tradingpost <tradingpost@lobo.net> wrote:
>
> I've been mentioning water issues before but it's not a glamorous subject
> apparently.
> paul tradingpost@lobo.net
> ~~~~~~~~~~~~~~~~~~~~~
>
> Groundwater Depletion Raises Likelihood of Global Food Crises
> September 27, 2010
> http://blogs.nationalgeographic.com/blogs/news/chiefeditor/2010/09/groundwater-depletion-food-crisis.html
>
> Water budgets are badly out of balance, throwing many regions into water
> debt.
> The water depleted annually could feed 940 million people for a year.
>
> By Sandra L. Postel, National Geographic Freshwater Fellow
>
> This post is part of National Geographic's Freshwater Initiative.
>
> Out of sight, out of mind means deep trouble when it comes to the reserves
> of freshwater stored underground. New numbers are out on the rate of
> groundwater depletion around the globe, and if they hold up to further
> scrutiny, the world is almost certainly facing a future of food shortages.
>
> In an upcoming issue of Geophysical Research Letters, a journal of the
> American Geophysical Union, Professor Marc Bierkens of Utrecht University
> in the Netherlands and his colleagues estimate that the rate at which
> humanity is pumping dry the underground reservoirs that hundreds of
> millions of people depend upon for food and drinking water more than
> doubled between 1960 and 2000.
>
> groundwater.jpgGlobal map of groundwater depletion, measured in millimeters
> of water per year, courtesy of American Geophysical Union.
>
> Using global groundwater data and hydrologic modeling to calculate the
> volumes of water added to and withdrawn from underground aquifers, the
> researchers estimate that groundwater depletion rose from 33
> trilliongallons (126 billion cubic meters) per year in 1960 to 75 trillion
> gallons (283 billion cubic meters) per year in 2000. The rate increased
> more or less linearly from 1960 up to the early 1990's, but then climbed
> sharply--likely due to escalating groundwater use in China and India.
>
> Although the research team doesn't delve into the implications of their
> findings, a lot is at stake--especially for the world's food supply.
> Irrigation, which accounts for 70 percent of world water use, is the
> principal cause of the groundwater depletion. About 40 percent of the
> world's food supply comes from the 18 percent of farmland that's irrigated,
> making irrigated farming a cornerstone of global food security. But in
> recent decades as more farmers have turned from rivers to groundwater for
> their water supply, groundwater pumping in many areas has become
> unsustainable.
>
> Just as a bank account shrinks when withdrawals exceed deposits, so does a
> groundwater account. Water budgets are badly out of balance, throwing many
> regions into water debt. In effect, farmers are using some of tomorrow's
> water to meet today's food demands.
>
> (Related: "How to Stem a Global Food Crisis? Store More Water" and "365
> Trillion Gallons of Water Thrown Away With Our Food Every Year.")
>
> It takes approximately 396,300 gallons (1,500 cubic meters) of water to
> produce one ton of grain. (That's an approximate average based on the water
> needed to produce rice, wheat and corn.) So the estimated 75 trillion
> gallons (283 billion cubic meters) of groundwater depleted in 2000 is
> sufficient to produce 188.6 million tons of grain. That's enough to feed
> 943 million people a subsistence diet for a year.
>
> The highest rates of water loss are occurring in critical regions of
> irrigated farming--including the north plain of China, northwestern India,
> and the central valley of California. In most areas groundwater is not
> monitored or regulated, so as increasing numbers of wells extract ever more
> water, the "tragedy of the commons" is playing out on a large scale.
>
> A little over a decade ago, I took a stab at estimating groundwater
> depletion using national-level data for China, India, the United States,
> North Africa and Saudi Arabia. For these regions, I came up with a net loss
> of 43 trillion gallons (164 billion cubic meters) a year. Adding in a
> ballpark estimate that inclusion of the rest of the world would bump this
> figure up by 25 percent, I arrived at a global depletion rate of 53
> trillion gallons (200 billion cubic meters) per year--not too far off from
> the 283 billion figure of this current study, which may lend a little
> confidence to both.
>
> This global assessment comes on the heels of regional studies that also
> corroborate the severity of the groundwater depletion problem. Using new
> satellite technology called GRACE - the Gravity Recovery & Climate
> Experiment - scientists with the University of California at Irvine and the
> National Atmospheric and Space Administration have estimated that
> California's Central Valley - the fruit and vegetable bowl for the nation -
> has lost a volume of groundwater equivalent to about two-thirds the volume
> of Lake Mead. Scientists with the U.S. Geological Survey have estimated
> that as of 2005, a volume of water equivalent to two-thirds of Lake Erie
> had been depleted from the Ogallala Aquifer, which supplies 30 percent of
> the groundwater used for U.S. irrigation. And in a 2009 study in Nature,
> again using the GRACE technology, scientists estimated that northern India,
> which encompasses that nation's breadbasket, is losing groundwater at a
> rate of 54 billion cubic meters per year, pla
> cing the livelihoods of 114 million people in that region at risk.
>
> (Read "NASA Satellites Track Vanishing Groundwater" in National Geographic
> News.)
>
> With modern satellite capabilities and new modeling and monitoring
> techniques, it is now possible to know what is happening to our water
> supplies underground. The picture is not good. The challenge now is to
> encourage the adoption of more efficient irrigation systems, more
> appropriate cropping patterns, and other measures to bring the world's
> groundwater accounts into balance. The future food security of hundreds of
> millions of people depends on this.
> ~~~~~
> Sandra Postel directs the independent Global Water Policy Project and
> lectures, writes, and consults on international water issues. She is also
> Freshwater Fellow of the National Geographic Society, and serves as lead
> water expert for the Society's freshwater initiative.
>
> Sandra is the author of several acclaimed books, including Pillar of Sand:
> Can the Irrigation Miracle Last? (W.W. Norton, 1999) and Last Oasis (W.W.
> Norton, 1997), which appears in eight languages and was the basis for a
> 1997 PBS documentary. She is also co-author, with Brian Richter, of Rivers
> for Life. Her essay "Troubled Waters" was selected for Best American
> Science and Nature Writing. She is a 1995 Pew Scholar in Conservation and
> the Environment.
>
>
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