| May 6, 2010 |  |
Heavy Flooding in Nashville and Global Warming: Is There a Connection?
NASHVILLE (May 6, 2010) — After the recent heavy rains and flooding in Nashville, many are wondering if this kind of extreme weather event will become more common as a result of global warming.
Below is a statement by Rich Hayes, deputy communications director at the Union of Concerned Scientists and a Nashville resident.
"A lot of my friends here have asked me if this disaster is related to global warming. The fact is that climate change increases the probability of some types of weather, including heavy rains and flooding. As average temperatures rise, more rain falls during the heaviest downpours. Unfortunately, that is exactly what we experienced in Nashville over the weekend.
"Warmer air holds more moisture. We've all seen it. Next time you take a shower, notice how the water vapor hangs in the warm air after you turn off the hot water. When warm air holding moisture meets cooler air in the atmosphere, the moisture can condense onto tiny particles to form floating droplets. If those drops get bigger and become heavy enough, they fall as precipitation.
"A report by 13 federal agencies last year found that one of the most pronounced precipitation trends in the United States is the increasing frequency and intensity of heavy downpours. More precipitation is falling during very heavy events, often with longer dry periods in between. Climate models project more heavy downpours and fewer light precipitation events.
"A record 13 inches of rain fell in Nashville on Saturday and Sunday, nearly twice the previous record set in 1979 following Hurricane Frederic. Very heavy rain and snow events, defined as the heaviest 1 percent of all precipitation events, now drop 67 percent more water on the Northeast, 31 percent more on the Midwest and 20 percent more on the Southeast than they did 50 years ago.
"If the fossil fuel emissions that cause global warming continue unabated, scientists expect the amount of rainfall during the heaviest precipitation events across the country to increase more than 40 percent by the end of the century. Even if we dramatically curbed emissions, these downpours would still increase, but by only a little more than 20 percent.
"It's going to take Nashville a long time to recover from the flooding. But when the flood waters do recede, and local officials turn to the question of how we plan for the future, they need to take climate change into account. Reducing emissions would make it easier to adapt, but Nashville and other cities had better plan for more nasty floods."
The Union of Concerned Scientists puts rigorous, independent science to work to solve our planet's most pressing problems. Joining with citizens across the country, we combine technical analysis and effective advocacy to create innovative, practical solutions for a healthy, safe, and sustainable future.
