The Greatest Water Crisis in the History of Civilization: Coming to the American West?
Continued from previous page
The simple rule of thumb for climate change is that wet places will get wetter and dry places drier. One reason the dry places will dry is that higher temperatures mean more evaporation. In other words, there will be ever less water in the rivers that keep the region’s cities (and much else) alive. Modeling already suggests that by mid-century surface stream-flow will decline by 10% to 30%.
Independent studies at the Scripps Oceanographic Institute in California and the University of Colorado evaluated the viability of Lake Mead and eventually arrived at similar conclusions: after about 2026, the risk of “failure” at Lake Mead, according to a member of the Colorado group, “just skyrockets.” Failure in this context would mean water levels lower than the dam’s lowest intake, no water heading downstream, and the lake becoming a “dead pool.”
If -- perhaps “when” is the more appropriate word -- that happens, California’s Colorado River Aqueduct, which supplies water to Los Angeles, San Diego, and the All-American Canal, which sustains the Imperial and Coachella Valleys, will go just as dry as the Central Arizona Project aqueduct. Meanwhile, if climate change is affecting the Colorado River’s watershed that harshly, it will undoubtedly also be hitting the Sierra Nevada mountain range.
The aptly named Lester Snow, a recent director of California’s Department of Water Resources, understood this. His future water planning assumed a 40% decline in runoff from the Sierras, which feeds the California Aqueduct. None of his contemplated scenarios were happy ones. The Colorado River Aqueduct and the California Aqueduct make the urban conglomerations of southern California possible. If both fail at once, the result will be, as promised, the greatest water crisis in the history of civilization.
Only Patricia Mulroy has an endgame strategy for the demise of Lake Mead. The Southern Nevada Water Authority is, even now, tunneling under the lake to install the equivalent of a bathtub drain at close to its lowest point. At a cost of more than $800 million, it will drain the dregs of Lake Mead for Las Vegas.
Admittedly, water quality will be a problem, as the dead pool will concentrate pollutants. The good news, according to the standard joke among those who chronicle Sin City’s improbable history, is that the hard-partying residents and over-stimulated tourists who sip from Lake Mead’s last waters will no longer need to purchase anti-depressants. They’ll get all the Zoloft and Xanax they need from their tap water.
And only now do we arrive at the third act of this expanding tragedy.
The Age of Thirst: Act III
Those who believe in American exceptionalism hold that the historical patterns shaping the fate of other empires and nations don’t apply to the United States. Be that as it may, we are certainly on track to test whether the U.S. is similarly inoculated against the patterns of environmental history.
Because tree rings record growing conditions year by year, the people who study them have been able to reconstruct climate over very long spans of time. One of their biggest discoveries is that droughts more severe and far longer than anything known in recent centuries have occurred repeatedly in the American Southwest. The droughts of the Dust Bowl in the 1930s, of the 1950s, and of the period from 1998 to 2004 are remembered in the region, yet none lasted a full decade.
By contrast, the drought that brought the civilization of the ancestral Puebloans, or Anasazi, centered at Chaco Canyon, to its knees in the twelfth century, by contrast, lasted more than 30 years. The one that finished off Mesa Verdean culture in the thirteenth century was similarly a “megadrought.”