As long as I can remember, I've heard environmentalists say that the American habitation of the Southwest was inherently unstable due to lack of water. That we were drawing down water supplies too fast to be replenished. All the while this was happening people continued moving to the Sun Belt in droves (living in newly constructed massive sprawling suburbs that were the epicenter of the housing bubble). Despite this, year after year, people in the PeakOil/climate change scene were claiming that places like Phoenix, Arizona and Las Vegas, Nevada, were "done for, over finished." Yet the migration from the Northern and Eastern parts of the country continued unabated. It seemed like an endless case of the Boy Who Cried Wolf.
Maybe the Wolf has finally arrived at the door:
The California Drought Is So Bad That A Flooded 1950s Ghost Town Was Exposed (Business Insider)
Drought-hit California unable to supply state water (BBC)
The unprecedented water crisis of the American Southwest (The Week)
California produces most of America's domestic produce as I recall.
P.S. The above image is from here: Urban Sprawl in the United States: 10 Incredible Aerials (Twisted Sifter)