Climate Change Is Stealing Even More Water from America's Desert Cities

Standing on the bank of the Colorado River as it sluggishly enters the canyon country of Utah, a muddy non-torrent about 75 feet across, it's supremely weird to think about its significance downstream. In this vast, dry region of ex-ocean now defined by feats of god-scale erosion, the river feels huge and unlikely. The barely comprehensible red and orange labrinyths of bottomless canyons within canyons within canyons the river carves out of solid rock in the next few hundred miles before exiting the Grand Canyon are one of the most impressive things on Earth, but it's somehow only when you get into the sprawling cities of the river's lower reaches does the river become truly god-like.

Places like Phoenix and Las Vegas and their ever expanding suburbs (and suburbs of suburbs of suburbs) are able to exist because of water siphoned away from the Colorado River via aqueducts and reservoirs like Lake Mead. In fact, so much water is taken that the river ends well before its natural terminus at the Gulf of California in Mexico. So, these are places, the fastest-growing places in the country actually, built on the promises of one river. But what happens when that river is a) not as big on average as originally thought, and b), getting smaller?

These are both real things. The first, as I went into a few weeks ago here, is the fault of unusually wet weather in the river's early days of being tapped for human uses. We now know the river runs quite a bit lower on average, based on historical tree ring analysis. But, secondly, there's climate change. A 2007 study projects a 9 percent drop in the river over the next 50 years due to increased temperatures and evaporation. A study out in Nature Climate Change today confirms that prediction, and suggests the situation is a bit worse. Researchers now expect a 10 percent drop in that time.

And 10 percent still might not sound that severe, but that 10 percent is five times the annual water usage of Las Vegas. There's really no way to engineer more water out of the river, unless you want to suggest building giant domes to keep water from being "lost" to evaporation. Better, let's take half of whatever that would cost (or whatever the cost of various pipeline projects proposed over the years to carry water from the wetter eastern states) and bribe people to, say, let it mellow and replace their sub-tropical landscaping with cacti and rocks, among other conservation measures that would make little to no impact on quality of life in the desert. That is, aside from allowing it to continue.

Reach this writer at michaelb@motherboard.tv.