Batten down the hatches, East Coasters: A new study argues that for every 1 degree C (1.8 degrees F) of global warming, the U.S. Atlantic seaboard could see up to seven times as many Katrina-sized hurricanes.
That’s the conclusion of Aslak Grinsted, a climatologist at Copenhagen’s Niels Bohr Institute, who led an effort to match East Coast storm surge records from the last 90 years with global temperatures. His results, published today in the Proceedings of the National Academy of Sciences, suggest that the strongest hurricanes are likely to become more commonplace with only half the level of warming currently projected by scientists.
“There is a sensitivity to warming, and it is surprisingly large,” Grinsted said.
The study compiled storm surge measurements from tide gauges at six locations on the East and Gulf coasts, filtering out the effects of seasonal cycles, daily tides, and overall sea-level rise to isolate the impact of storms. Next, these records were stacked against both global temperatures and a series of other climatic factors, like natural water temperature cycles and regional rainfall. The result? Global temperatures turned out to be one of the best predictors for hurricane activity. Using computer models, Grinsted found that a 1-degree-C rise in global temperatures could multiply extreme hurricane frequency by two to seven times.