The Chihuahuan Desert in New Mexico (and presumably Chihuahua as well, but the Mexican side of the drought is completely ignored by most environmental journalists) is undergoing what ecologists call “state change,” where the grasslands are declining into a permanent scrub desert that radically transforms the ecosystem. This has resulted from a combination of climate change and overgrazing. The overgrazing create enormous ecological degradation, but that could be restored at least to some extent under the old ecological conditions. Now, it seems highly unlikely.
The future of human habitation in the American southwest is quite unclear with a non-zero possibility that cities from Denver to Las Vegas to Phoenix to El Paso could be more or less abandoned over the next century because the environment (specifically water supplies) simply won’t be able to carry this many people in those places. This would be catastrophic to the economy, although perhaps not more so than the near certainty that Miami is doomed and probably New Orleans as well.