Tuesday, March 6, 2012

With climate change, today's '100-year floods' may happen every three to 20 years: research

Last August, Hurricane Irene spun through the Caribbean and parts of the eastern United States, leaving widespread wreckage in its wake. The Category 3 storm whipped up water levels, generating storm surges that swept over seawalls and flooded seaside and inland communities. Many hurricane analysts suggested, based on the wide extent of flooding, that Irene was a “100-year event”: a storm that only comes around once in a century.

However, researchers from MIT and Princeton University have found that with climate change, such storms could make landfall far more frequently, causing powerful, devastating storm surges every three to 20 years. The group simulated tens of thousands of storms under different climate conditions, finding that today’s “500-year floods” could, with climate change, occur once every 25 to 240 years. The researchers published their results in the current issue of Nature Climate Change.

MIT postdoc Ning Lin, lead author of the study, says knowing the frequency of storm surges may help urban and coastal planners design seawalls and other protective structures.

“When you design your buildings or dams or structures on the coast, you have to know how high your seawall has to be,” Lin says. “You have to decide whether to build a seawall to prevent being flooded every 20 years.” Read More