Read the full article by Doug Struck, The Washington Post, August 20, 2007.
Excerpts
As global warming heats the planet, there will be more desperate measures. The climate will be wetter in some places, drier in others. Changing weather patterns will leave millions of people without dependable supplies of water for drinking, irrigation and power, a growing stack of studies conclude.....Comment: I recently read that most Republicans don't believe the scientific evidence is conclusive that global warming is a problem. I hope it does not take another American dust bowl disaster to convince them. If so, it may be too late. JAD
Stephen Schneider, editor of the journal Climatic Change and a lead author for the authoritative Intergovernmental Panel on Climate Change (IPCC), pours himself a cup of tea and says the future is clear."As the air gets warmer, there will be more water in the atmosphere. That's settled science," he said. But where, and when, it comes down is the big uncertainty.
"You are going to intensify the hydrologic cycle. Where the atmosphere is configured to have high pressure and droughts, global warming will mean long, dry periods. Where the atmosphere is configured to be wet, you will get more rain, more gully washers.
"Global warming will intensify drought," he says. "And it will intensify floods."
According to the IPCC, that means a drying out of areas such as southern Europe, the Mideast, North Africa, South Australia, Patagonia and the U.S. Southwest.
These will not be small droughts. Richard Seager, a senior researcher at Lamont-Doherty Earth Observatory of Columbia University, looked at 19 computer models of the future under current global warming trends. He found remarkable consistency: Sometime before 2050, the models predicted, the Southwest will be gripped in a dry spell akin to the Great Dust Bowl drought that lasted through most of the 1930s.The spacing of tree rings suggests there have been numerous periods of drought going back to A.D. 800, he said. But, "mechanistically, this is different. These projections clearly come from a warming forced by rising greenhouse gases."....
Seager predicts that drought will prompt dislocations similar to those of the Dust Bowl. "It will certainly cause movements of people. For example, as Mexico dries out, there will be migration from rural areas to cities and then the U.S.," he said. "There is an emerging situation of climate refugees."
Global warming threatens water supplies in other ways. Much of the world's fresh water is in glaciers atop mountains. They act as mammoth storehouses. In wet or cold seasons, the glaciers grow with snow. In dry and hot seasons, the edges slowly melt, gently feeding streams and rivers. Farms below are dependent on that meltwater; huge cities have grown up on the belief the mountains will always give them drinking water; hydroelectric dams rely on the flow to generate power......
The potential for conflict is more than theoretical. Turkey, Syria and Iraq bristle over the Euphrates and Tigris rivers. Sudan, Ethiopia and Egypt trade threats over the Nile. The United Nations has said water scarcity is behind the bloody wars in Sudan's Darfur region. In Somalia, drought has spawned warlords and armies.
Already, the World Health Organization says, 1 billion people lack access to potable water. In northern China, retreating glaciers and shrinking wetlands that feed the Yangtze River prompted researchers to warn that water supplies for hundreds of millions of people may be at risk.
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