February 14, 2012
Climate Change Could Speed Up Storm Frequency
According to new research by MIT, climate change could make events like last year's Hurricane Irene happen every three to 20 years, instead of once a century.
The group simulated trends of thousands of storms under different climate conditions and found that today's "500-year floods" could occur once every 25 to 240 years.They said knowing the frequency of storm surges may help urban 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,” MIT postdoc Ning Lin, lead author of the study, said in a press release. “You have to decide whether to build a seawall to prevent being flooded every 20 years.”
The researchers looked at the impact of climate change on storm surges and used New York City as a case study.
They combined four climate models with a specific hurricane model in order to simulate future storm activity in the region.
The models generated 45,000 synthetic storms within a 125-miles radius of Battery Park in Manhattan.
The team then studied each climate model under two scenarios, the first scenario being a "current climate" condition and the second a "future climate" condition.
After simulating storms in the region, the researchers simulated the resulting storm surges using three different models, including one used by the National Hurricane Center (NHC).
The NHC uses a storm-surge model to predict the risk and extend of flooding from the impending storm. However, these models have not been used to evaluate multiple simulated storms under a scenario of climate change.
A "100-year storm" in New York means a surge flood of about 6 feet. A "500-year storm" means the region experiences 10.5 feet of surge floods. Under both scenarios, Lin said that water would reach above Manhattan's seawalls, which stand about 5-feet high.
“The highest [surge flood] was 3.2 meters (10.5 feet), and this happened in 1821,” Lin said. “That´s the highest water level observed in New York City´s history, which is like a present 500-year event.”
Carol Friedland, an assistant professor of construction management and industrial engineering at Louisiana State University, said the researchers' findings could prove to be a useful tool to inform coastal design.
“The physical damage and economic loss that result from storm surge can be devastating to individuals, businesses, infrastructure and communities,” Friedland said. “For current coastal community planning and design projects, it is essential that the effects of climate change be included in storm-surge predictions.”
The research was published in the journal Nature Climate Change.
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