Global temperature increases could boost hurricane-caused flooding

By Erin Wayman

Web edition: March 18, 2013
Print edition: April 20, 2013; Vol.183 #8 (p. 18)

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Extreme storm surges, like the one that hit the Gulf Coast during Hurricane Katrina, will become more common as global temperatures rise, a new study finds.

Credit: LCDR Mark Moran/AOC/NMAO/NOAA Corps

As the climate warms, deadly flooding caused by storm surges will occur more frequently, scientists predict.

A storm surge is the rise in water above normal tide level that occurs when hurricanes push water toward a coast. In 2005, Hurricane Katrina smacked the Gulf Coast with a storm surge of up to 8.5 meters. During the 20th century, storm surges of this magnitude hit the United States about once every 10 to 30 years.

To calculate how the frequency of extreme storm surges will change, Aslak Grinsted of Denmark’s University of Copenhagen and colleagues combined records of storm surges in the southeastern United States since 1923 with several climate simulations. For every one degree Celsius increase in global temperature, the results suggest, large storm surges will become two to seven times as frequent, the team reports March 18 in the Proceedings of the National Academy of Sciences.

In 2007, the Intergovernmental Panel on Climate Change estimated that global temperatures could increase by 2 to 4 degrees Celsius by 2100.