Edging Into Uninhabitability

Phoenix: where the temperature may soon not drop below 100 degrees F at night in High Summer:

Sixty years ago, when Phoenix was just embarking on its career of manic growth, nighttime lows never crept above ninety. Today such temperatures are a commonplace, and the vigil has begun for the first night that doesn’t dip below 100. Studies indicate that Phoenix’s urban-heat-island effect may boost nighttime temperatures by as much as ten degrees. It’s as though the city has doubled down on climate change, finding a way to magnify its most unwanted effects even before it hits the rest of us full blast.

...Phoenicians who want to escape water worries, heat waves and haboobs have traditionally sought refuge in the cool green forests of Arizona’s uplands, or at least they did until recently. In 2002, the Rodeo-Chediski fire consumed 469,000 acres of pine and mixed conifer on the Mogollon Rim, not far from Phoenix. It was an ecological holocaust that no one expected to see surpassed. Only nine years later, in 2011, the Wallow fire picked up the torch, so to speak, and burned across the Rim all the way to the New Mexico border and beyond, topping out at 538,000 charred acres.

...Compared to Phoenix’s other heat and water woes, the demise of Arizona’s forests may seem like a side issue, whose effects would be noticeable mainly in the siltation of reservoirs and the destabilization of the watersheds on which the city depends. But it could well prove a regional disaster. Consider, then, heat, drought, windstorms and fire as the four horsemen of Phoenix’s Apocalypse. As it happens, though, this potential apocalypse has a fifth horseman as well.

...Drought divides people, and Phoenix is already a divided place—notoriously so, thanks to the brutal antics of Maricopa County Sheriff Joe Arpaio.