Tuesday, February 14, 2012

100-Year Floods May Happen Every 3 to 20 Years, Say MIT and Princeton Researchers

 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.
Climate change is warming the oceans and preventing water layers from mixing, which could upset the carbon storage capacity of microbes and plankton.
As the ocean surface warms, evidence shows that it will become more “stratified”, or confined to layers that mix less than they did in the past.
This should reduce overall ocean productivity, but so little is known about the effect on ocean microbes that the implication for carbon sequestration and global warming is less clear, said Stephen Giovannoni, professor of microbiology, Oregon State University, who led the study. More