Surviving a warmer world: Global forecast is 'mostly dry'

Climate change is already being blamed for altered rainfall patterns and shrinking glaciers that provide water for drinking and agriculture. Part 1 of an occasional series.

from the April 5, 2007 edition

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"One says there's going to be more snow; one says there's going to be less snow," he says. But planning for severe, prolonged droughts has always been part of the planning process, he says.

Over the long term, population growth is likely to push other water-saving approaches to the fore, such as desalination of brackish underground water and reuse of municipal wastewater for drinking. At least six cities in the state are considering wastewater-to-drinking-water conversions either through a direct treatment and recycling system or by using treated wastewater to recharge aquifers.

Ironically, such efforts could make it more difficult for the state to balance the competing demands of its urban and rural interests. It will also be harder to meet its obligations to send some of its river water on to Texas, says John D'Antonio, New Mexico's state engineer.

In the West, agriculture consumes most of the water. Many farmers here are installing more-efficient irrigation systems that lose less water to seepage as it moves along irrigation ditches. But that "leaking" water also contributes to groundwater reserves. Now less water is finding its way back into aquifers.

Water is a finite resource, Mr. D'Antonio notes. If rivers are full subscribed, the only way for the state to grow is to transfer water rights in an orderly way from agriculture to urban uses.

A thirsty world responds to scarcity

How issues like these will play out around the world will depend on many factors, including whether countries can work out disputes over water resources.

So far, the record is patchy. In the Philippines, researchers from Columbia University are trying to help the city of Manila set up a water-leasing deal with nearby farmers. The city and farmers share a small reservoir – and recurring drought.

But in dry years, the city typically has just taken all the water it needed, leading to "massive agricultural losses," says Casey Brown, a member of the group working on the water-lease project. The hope is to set up a plan under which the

city would pay the farmers for the water it takes during droughts – providing, among other things, an added economic incentive for the city to conserve during dry years.

Political instability can get in the way, too.

Iraq, Syria, and Turkey have formed a joint commission on water issues, but it hasn't met since the first Gulf War in 1992, says Olcay Unver, a visiting scholar at the Water Resources Research Institute at Kent State University in Kent, Ohio.

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