Climate Change Threatens to Dry up the Southwest's Future

The high ceilings of the Miracle Mile shopping mall in Las Vegas's Planet Hollywood Hotel and Casino are painted to resemble a perfect-day sky -- the soft blues and downy white clouds of an idealized spring. About every hour, the scene is interrupted by "the rainstorm." The sky darkens, a thunder soundtrack rumbles as strobes mimic lightning, and a one-minute sprinkle comes down from the ceiling. The water falls into a shallow pool set between an Aldo Shoes and a Ben & Jerry's. As smoke machine fog rises off the pool's surface, onlookers snap photographs.

The wet weather show at Planet Hollywood is a large leap from the reality outside, where tourists wither beneath the pounding heat that, on a June evening, remains in the triple digits past 6 p.m. In Las Vegas, rain is rare: a scant four inches a year, about half of what Tucson, AZ receives. A rainstorm in the Mojave Desert, whether man-made or natural, is an unusual event worth photographing.

One could easily forget that, though, on a tour around the booming city. At Lake Las Vegas, a multi-resort and casino about 30 miles from the city center, grass lines the roads and a faux waterfall tumbles down boulders at the resort entrance. Across town, on the city's affluent west side, sod decorates the front of auto dealerships. Homeowners at a gated community called "Beach View Estates" enjoy private docks on their local fake lake. Driving Las Vegas's broad boulevards, the green tops of palm and pine trees often obscure the bare, red mountains that ring the city.

This amazing oasis is made possible by Lake Mead, located a 45-minute drive from the Strip. The lake -- which stretches for 110 miles when full -- is a marvel of modern engineering. Capable of holding nearly nine trillion gallons of water, the lake stands out like a vast sapphire amid the rust-colored cliffs and sharp peaks.

Lake Mead is so huge that for generations it was difficult to conceive that it would ever be at risk of being drained. Now, something is amiss. From the shore, even a casual glance reveals that the lake is shrinking. A bright white stripe encircles the lake edge, marking the more than 100-foot-drop from the "normal" water level. Ancient desert spires, once submerged, have reappeared, now as islands. Lake Mead is only half full.

The bleached white rock surrounding the lake marks a sharp dividing line between a now-evaporating era when the Southwest exploded in population and an uncertain future that is forcing the region's leaders to ask whether they can keep the water flowing.

The Mojave and Sonora Deserts, home to millions of people, are formidably hot and dry places. Modern life in the region is possible only because of a system of reservoirs that collects the precipitation from hundreds of thousands of square miles and stores it. According to climate models, the region is set to become even hotter and drier -- and, for water managers, more formidable. Some desert communities may find relief by transferring water from other areas. But as climate change forces water levels down, efforts to cut CO₂ emissions will push energy prices upward, making some large-scale water transfers uneconomical. The abundant water and cheap energy that have fueled the Southwest's transformation are starting to dry up.

"By 2025 or so we are headed for a train wreck in the West," says Tim Barnett, a researcher at the Scripps Institution of Oceanography, who co-published a study that concluded Lake Mead would be empty by 2021 at current consumption rates. "The truth of the matter is that the Bureau of Reclamation will not let the reservoir go dry. They will just cut off deliveries. And that will send shivers down your spine, because someone will not get the water they are expecting.