Columbia University study ties southeast drought to population
Posted Oct 4, 2009 by Michael Krebs
With the world's governments working feverishly to create climate change legislation standards, a Columbia University study on drought conditions in the southeast disputes prior conclusions on the ties to global warming.
European leaders and worldwide environmental organizations have been pressuring the United States to move forward with a climate change bill. It's part of an ongoing effort to further the pressure on India and China to comply with emission standards and to help shape a global continuity on cap-and-trade legislative structure. To this end, there have been numerous attempts to attach randomly-occurring weather events to a bigger global warming umbrella – and to create a sense of urgency for the U.S. Congress to act.
However, science has largely not supported these claims. The latest example of this lack of support can be found in a study from Columbia University on the underlining causes of a long drought in America's southeast region.
The Columbia researchers found that the severe shortage was directly attributed to a significant rise in population growth. Prior explanations for the southeast drought centered on rainfall amounts and concluded falsely that global warming was to blame.
The team analyzed data from weather instruments and compared the numbers with regional data that spanned a century. This information yielded findings that were “pretty normal and pretty typical by standards of what has happened in the region over the century.”
The connection between water scarcity and population growth is consistent with what has been experienced elsewhere in the world.
I am not going to criticize any governments for what they did or did not do, Douglas LeComte, a drought specialist at the Climate Prediction Center of the National Weather Service, told The New York Times. But if you have more people and the same amount of water storage, you are going to increase the impact of droughts.
Southeast Drought Study Ties Water Shortage to Population, Not Global Warming
By CORNELIA DEAN
New York Times
October 2, 2009
The drought that gripped the Southeast from 2005 to 2007 was not unprecedented and resulted from random weather events, not global warming, Columbia University researchers have concluded. They say its severe water shortages resulted from population growth more than rainfall patterns.
The researchers, who report their findings in an article in Thursdays issue of The Journal of Climate, cite census figures showing that in Georgia alone the population rose to 9.54 million in 2007 from 6.48 million in 1990.
At the root of the water supply problem in the Southeast is a growing population, they wrote.
Richard Seager, a climate expert at the Lamont-Doherty Earth Observatory who led the study, said in an interview that when the drought struck, people were wondering whether climate change linked to a global increase in heat-trapping gases could be a cause.
But after studying data from weather instruments, computer models and measurements of tree rings, which reflect yearly rainfall, our conclusion was this drought was pretty normal and pretty typical by standards of what has happened in the region over the century, Mr. Seager said.
Similar droughts unfolded over the last thousand years, the researchers wrote. Regardless of climate change, they added, similar weather patterns can be expected regularly in the future, with similar results.
In an interview, Douglas LeComte, a drought specialist at the Climate Prediction Center of the National Weather Service, said the new report makes sense. Although Weather Service records suggest the 2005-7 drought was the worst in the region since the 1950s, Mr. LeComte said, we have had worse droughts before.
Some climate models developed by scientists predict that the Southeast will be wetter in a warming world. But the Columbia researchers said it would be unwise to view climate change as a potential solution to future water shortages.
As the regions temperature rises, there may be more rain, they wrote, but evaporation will increase, possibly leaving the area drier than ever.
Mr. LeComte said that creating greater water storage capacity say, in reservoirs could mitigate drought effects in areas where population was rising.
I am not going to criticize any governments for what they did or did not do, he said. But if you have more people and the same amount of water storage, you are going to increase the impact of droughts.
The researchers said rainfall patterns in the Southeast were linked only weakly to weather patterns like La Nia and El Nio, the oscillating warm and cold conditions in the eastern Pacific linked to precipitation rates in the Southwestern United States.
Instead, they wrote, any variation in rainfall in the Southeast commonly arises from internal atmospheric processes and is essentially unpredictable.