Goodbye Pools, Lawns and a Whole Lot More: Why Life in the Southwest as We Know it Will Be History
Stay up to date with the latest headlines via email.
This piece first appeared in Worldchanging.
It is likely to be a source of unhappiness for us that we have taken natural bounty for granted in designing our civilization. But it is likely to prove tragic that we have assumed not only the indestructibility of nature (heck, some fossils still argue that climate change is impossible because it is not within human abilities to wreck the climate), but also that the particularly beneficial circumstances of the 20th century are what is ecologically "normal." Nowhere is this more evident than in arid regions, and nowhere is it better studied than in the American Southwest.
There, in the deserts and mountains, we Americans have built huge cities, farms and ranches, and one of the world's leading tourism industries (think Vegas) predicated on the reliability of cheap, plentiful water. This was a mistake. Water in the very near future will be neither cheap nor plentiful, and much of the Southwest is destined for real trouble.
I have not read a clearer explanation of how much trouble the Southwest is in for, or a better accounting of the flawed thinking that got us into this mess, than James Lawrence Powell's excellent Dead Pool: Lake Powell, Global Warming, and the Future of Water in the West. Powell lays out, with devastating precision and a wealth of facts, the reality that the Southwest as we've known it over the last 50 years is already done for.
First, our assumptions about how wet the American West actually is have been based on a century that studies of tree rings show to have been anomalously wet: over the centuries, the region's usual state has been even drier than it is now.
Second, though climate change is expected to lead to more rainfall during wet years, in the West's four major river basins (the Columbia, Missouri, Rio Grande and Colorado), the number of hot years expected as climate change worsens will be several times the number of wet years.
Third, rising temperatures mean that the mountain snowpacks upon which all four rivers rely are going to continue shrinking. This is particularly a problem for the Colorado River basin, where evaporation into the desert air is so fast that "nearly 90 percent of the water in the streams must come from a virtual reservoir: the Rocky Mountain snowfields." But snow pack in the Rockies has already declined by 16 percent, and is expected to shrink far more, and far more quickly, in coming years.
Fourth, our other options for taking, storing and using water have run out. Aquifers are essentially fossil water, and are being depleted many, many times faster than they can refill. For our purposes, Western aquifers are non-renewable resources. New dams designed to catch winter and spring rain in wet years and store it for dry years are impractical in scale, financially and politically. There is, realistically, very little we can do to increase water supply, or even to keep it from disappearing rapidly.
How rapidly? Powell cites recent studies that with current water demand and even very minor climate change (which is not what we should expect now) there's a 50 percent chance that both Lake Powell and Lake Mead (the two largest reservoirs in the U.S.) will "reach dead pool" by 2021. That means so little water will be left in them that the water level falls below their dam's lowest outlets (and so no more water flows from them). As Powell notes, "A probability of 50 percent means that there is an equal chance that the reservoirs could fall to dead pool later -- or sooner ." [his emphasis] The take away is that, unless profound changes are made, the desert Southwest will run out of water in the next couple decades.