Drought Considered Mild, Study Says

The 2005-2007 drought was actually mild compared to many others, and in fact no worse than one just a decade ago, according to researchers from Columbia University’s Lamont-Doherty Earth Observatory. The problem, researchers concluded, was how quickly the population has grown over the last 10 years. Climate change played no detectable role.

“The drought that caused so much trouble was pathetically normal and short, far less than what the climate system is capable of generating,” said lead author Richard Seager, a climate modeler at Lamont. “People were saying that this was a 100-year drought, but it was pretty run-of-the-mill.”

Nationwide, the drought ran from late 2005 to winter 2007-2008. During the worst of the dry period, Atlanta’s main reservoir sank more than 14 feet. Usage restrictions were declared in many areas, and states became embroiled in lawsuits among themselves and with the federal government over use of water in rivers and reservoirs. However, when scientifically compared to weather records of the past, the recent drought was relatively mild.

The factor that has changed is population. In 1990, Georgia, which uses a quarter of the southern region’s water, had 6.5 million people. By 2007, there were 9.5 million—up almost 50 percent in 17 years. The population is still rising, driven largely by migration. However, little has been done to increase water storage or reduce consumption. There has been increased sewage discharge near water supplies, and vast tracts of land have been covered with impermeable roofs, roads and parking lots, which drain rainfall away rapidly instead of storing it.

“It was a lot drier in the 19^th century than it has been recently, but there were so few people around, it didn’t harm anyone,” said Seager. “Now, we are building big urban centers that make us vulnerable to even slight downturns.”