Drought and shrinking water supplies could pose serious limits to growth in the American southwest and southeast.
"More than anything else, lack of water could define the limits to America's future growth. If global warming, manmade or otherwise, is contributing to a drying out of both the Southeast and the Southwest, then that's trouble, because those regions are where people are headed: older people, in search of cheap land and dry heat, and younger people chasing jobs in high-tech industries that are shifting south, attracted by lower taxes and laissez-faire state governments.
Arizona is the fastest-growing state in the union. Its population increased by 3.6 per cent last year. Nevada is No. 2: Its population grew by 3.5 per cent. Both are mostly desert.
Tuscon and Phoenix - with populations of a million and four million, respectively - are sprawling toward each other, and are expected to merge in the next decade. Planners project a Phoenix-Tucson population of 10 million within 30 years. Even without worsening drought, that will exceed the capacity of existing water supplies - and Phoenix has supplemented its groundwater supplies by diverting rivers, such as the Colorado. Further increasing Phoenix's water capacity could mean impoverishing water supplies elsewhere.
The long-term prospects for Southern California are deeply troubling. A recent study by the Lamont-Doherty Earth Observatory at Columbia University warns that global warming, though it will actually increase precipitation overall, will entrench current dry conditions in the American southwest permanently within a couple of decades...Global warming or no, there will be future droughts, and no one expects anything other than continued growth in the southeast and southwest."