People who enjoy the hot, arid conditions of desert living -- and relatively lower home prices -- may soon find the cost of water shortages and rising temperatures are more than they bargained for.
Desert regions not only yield more affordable housing because of their relatively remote and challenging environments, they also hold the possibility of new global economies.
Unfortunately, climate change in cactus country is producing weather even the knarliest desert denizen is finding tough to survive, according to "Global Deserts Outlook".
According to the assessment of the world's deserts, released this summer and conducted by the United Nations Environment Programme (UNEP), the UN's environmental watchdog, almost one-quarter of the earth's land surface -- 33.7 million square kilometers (13 million square miles) -- has been defined as "desert."
It's home to more than a half billion people and in the near future it could be home to many who didn't choose the full monty.
Among the most densely populated deserts are the Sonoran Desert in southwest Arizona and southeast California and the Chihuahuan Desert which stretches from southeastern Arizona, to southern New Mexico and western Texas. Both deserts also dip below the border into Mexico.
The already rugged environments are just beginning to really feel the heat.
"Climate change as a result of human-made emissions is already affecting deserts. The overall temperature increase of between 0.5 and 2 degrees Celsius (1 to 3 degrees Fahrenheit) over the period 1976-2000 has been much higher than the average global rise of 0.45 degrees Celsius," according to UNEP.
That's just for starters. The Intergovernmental Panel on Climate Change (IPCC), the body of scientists advising governments and UNEP, says temperatures in deserts could rise more, by an average of as much as 5 to 7 degrees Celsius (about 9 to 12 degrees Fahrenheit) by as soon as 2071.
This summer, residents in the southwest, among others experiencing recording breaking heatwaves, are all too aware of similarly higher temperature changes just this summer compared to last summer.
Higher temperatures have profound implications for both the water supply and the delicate desert ecosystem.
The report says underground water supplies, some centered around oases and areas formed over thousands, and in some cases, over a million years, are increasingly being drained of water for agriculture and settlements including retirement resorts.
Renewable supplies of water, fed to deserts by large rivers, are also expected to be threatened severely by as early as 2025. That includes the Rio Grande and Colorado Rivers in North America along with the Gariep River in southern Africa; the Tigris and Euphrates in southwestern Asia and the Amu Darya and Indus Rivers in central Asia, the report says.
"A large fraction of the water used for agricultural and domestic purposes in the arid southwest of the United States, the deserts of Central Asia and the Atacama and Puna Deserts on both sides of the Andes is drawn from rivers that originate in glaciated/snow-covered mountains," which are now thawing out at unexpected rates.
"Water is a vital and limiting factor in deserts. Many life forms exist in limbo, suddenly bursting into fruit and reproducing in vast numbers in response to 'rain pulses.' Water supply is also vital for human settlements and these are even more vulnerable to unsustainable withdrawals of water," UNEP reports.
Just as global warming is beginning to cause higher sea levels to nip at the coastlines, higher temperatures generate desertification, pushing the desert frontier out, closer to populations centers typically situated on the desert fringes.
That could force a desert lifestyle on those who didn't bargain for the full deal, the report says.
What's worse, high temperatures are deadly.
More people in the U.S. die from extreme heat than from hurricanes, lightning, tornadoes, floods, and earthquakes combined according to the Centers for Disease Control.
That's all unfortunate because technology exists today that can serve deserts a destiny as carbon-free commerce centers with historic economic clout -- clout that could help turn the tables on global warming.
"If the huge, solar-power potential of deserts can be economically harnessed, the world has a future free from fossil fuels. And tourism based around desert nature can, if sensitively managed, deliver new prospects and perspectives for people in some of the poorest parts of the world," says Shafqat Kakakhel, UNEP's deputy executive director.
But the planet and its deserts are running out of time.
"Faster climate change is already happening and most climatologists believe that its acceleration is inevitable, whatever the cause, and almost whatever the response: it may be too late to intervene to change the trajectory of the next few decades. Temperatures, and with them evaporation (and hence aridity), will almost certainly rise further, which may or may not be compensated by increased rainfall," the report says.
