Critical water shortages in U.S. from global warming

And now add drought to the list of probable near-term consequences of global warming.

A study by Terra Tech for the Environmental Defense Council predicts that over 1,100 counties in the 48 continguous States (more than 1/3 of them) “will face higher risks of water shortages by mid-century [2050] as the result of global warming. More than 400 of these counties will face extremely high risks of water shortages.” (Climate Change, Water, and Risk: Current Water Demands are not Sustainable [“Fact Sheet”], p1.)

Global warming’s contribution to the forthcoming shortages (population growth and unchecked increased consumption would put strains on the system in any event) comes in two respects: changes in precipitation and potential evapotranspiration (PET) (p2). “Evapotranspiration is the sum of evaporative loss of water from the ground surface and transpiration losses through vegetation. PET is a calculated metric used to represent evapotranspirative losses under idealized conditions, where a full water supply is available for evapotranspiration. Together, changes in precipitation and potential evapotranspiration have significant effects on available precipitation, estimated as water falling either as rain or snow that would not be consumed by the potential evapotranspiration.” (p2.) Increased temperatures will increase PET. The study suggests 4 to 5 inches of water loss in increased PET. In Southern States the increase in PET is estimated at 5 to 6 inches per year.

Moreover, precipitation change will be uneven. In the Northeast, Northwest and Southeast, precipitation will average 15 inches per year. Some areas of east Texas, the Lower Mississippi Basin, California Central Valley and the Southeastern US will experience a decrease in current precipitation by more than 5 inches per year by 2050. The full version of the report, entitled “Evaluating Sustainability of Projected Water Demands under Future Climate Change Scenarios” (pdf files: low resolution version, high resolution version) contains two detailed maps on page 13. One has the projected changes in precipitation (in inches) from 1961-1990 to 2040-2059. The Eastern portion of the country from North Carolina northward and extending to mid-Illinois is projected to have increased precipitation of more than 4 inches per year. By contrast Texas and Southern Florida are predicted to have decreases of more than 1 inch. Nevada, Colorado, Utah, Arizona and New Mexico are also shown to have decreased participation. The second map shows expected temperature increases (in ºC) between averages during the period 1961-1990 and the period 2020-2039. Interestingly, the west coast north of San Francisco and Florida are projected to have increases less than 1.25º C. The largest projected increase is shown to be in the rust belt and Utah (with increases of up to 2º C). Page 17 (figure 12) contains a county-by-county map of the projected changes in available precipitation between 2005 and 2050. Substantial decreases (from 2.5 to 5 inches) are seen from Arizona through Florida and northward through the bread belt. Various additional maps provide county-by-county projected water demands and withdrawals. Finally, on p22 (Figure 17) are two county-by-county maps showing the Water Sustainability Index under the projected climate change scenario and under the assumption of no climate change. The first map shows extreme situations in southern California, southern Nevada, all of Arizona, all of Texas, large parts of Oklahoma, Kansas, Nebraska and Florida.

The Fact Sheet concludes:

“While water management and climate change adaptations plans will be essential to lessen the impacts, they cannot be expected to counter the effects of a warming climate. One reason is that the changes may simply outrun the potential for alternatives such as modifying withdrawals, increasing water use efficiency, increased water recycling, enhancing groundwater recharge, rainwater harvesting and inter-basin or inter-county transfers to make up for water deficits.” (final page.)

And therefore the answer must come from a program to deal with climate change itself. This is so because “the pressure on water supplies will not cease in 2050. If climate warming continues to increase, we can expect the risks of water shortages to increase with it. There is no way to truly manage the risks exposed by this report other than taking the steps necessary to slow down and reverse the warming trend. Doing so requires Congressional action and global leadership.” (id.) I suppose that in light of the Copenhagen Climate Conference and the Senate’s decision to let cap-and-trade legislation die this session, we can only really hope for a Deus ex machina. The sad part is that most global warming deniers, actually do believe there will be a Deus ex machina.

One could also look at the situation the way a high capitalist does, for there is never any catastrophe so dire or future so dim that there isn’t a hope to make money off of other people’s misery. And there already are capitalists proclaiming that “China’s Water Crisis Is an Investment Opportunity.” Perhaps there is opportunity to monopolize the U.S. water supply and then we could see the benefits of capital as Demetrio Aguilera-Malta showed in Seven Serpents and Seven Moons where the water baron was so fabulously rich that he could afford to buy a boy to have him stand like a statue while a rose bush grew through his hand.

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