Study: Flood Risk Rising for New York City, New Jersey Coast

A new study looking back over 1,000 years finds the flooding risk along the New York and New Jersey coasts increased greatly after industrialization, and major storms that once might have occurred every 500 years could soon happen every 25 years or so.

The study by Penn State, Rutgers, Princeton, and Tufts universities, and Massachusetts Institute of Technology, finds that flood heights have risen nearly 4 feet since the year 850, largely because of a sea level rise. The study advocates better risk management strategies to cope with storms.

“A storm that occurred once in seven generations is now occurring twice in a generation,” said Benjamin Horton of Rutgers, one of six lead researchers involved in the study. “What we do know is that as sea level rise accelerates into the future, we are going to have more frequent flooding.”

The study was published Sept. 28 in the Proceedings of the National Academy of Sciences journal.

Adam Sobel, an atmospheric scientist at Columbia University and author of the book “Storm Surge” about Superstorm Sandy, said this study, like many others before it, leaves little doubt that sea level rise will be more rapid than it has been before.

“This is just one more good study adding certainty to what we know already, which is that coastal cities around the world — including New York, but we’re not the only one, nor the worst — are in trouble,” he said. “This makes the direction of change certain: We are at increasing risk for Sandy-like disasters here in New York City and in many other places as well.”

To reconstruct sea levels for earlier periods, the research team used microfossils, called foraminifera, that were preserved in sediment cores from coastal salt marshes in Cape May Court House and Galloway, New Jersey. The ages of these cores were estimated using radiocarbon dating and other techniques.