He writes U.S. farmers are withdrawing unsustainable volumes of groundwater to irrigate their crops,resulting in an accelerating decline in aquifers across the
central and western United States, according to a new report by the U.S. Geological Survey (USGS).
Groundwater resources have shrunk by 1,000 cubic kilometres since 1900 as the amount of water extracted exceeds the rate at which aquifers are recharged, according to “Groundwater depletion in the United States.” This about double the total amount of water contained in Lake Erie.
And depletion rates are accelerating. The 40 aquifers in the USGS survey declined almost 200 cubic kilometres between 2000 and 2008 alone - a record rate of 24 cubic kilometres per year, which is more than double the 11 cubic km per year lost in the 1990s and the 12 cubic km lost each year in the 1980s.
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