Within the next three decades, floods that used to strike the New York City area only once every 500 years could occur every five years, according to a new study released just days before the fifth anniversary of Superstorm Sandy. The study, performed by researchers at several universities and published in the Proceedings of the National Academy of Sciences, primarily blames the predicted change on sea-level rise caused by global warming. "This is kind of a warning," says Andra Garner, a Rutgers University scientist and study co-author. "How are we going to protect our coastal infrastructure?" The researchers based their analysis on models that factored in predictions for sea level rise and possible changes in the path of future hurricanes.
Many of the models had a dose of good news for the nation's largest city: Climate changes may mean that storms are more violent, but are also likely to swing further offshore, meaning storm surge heights aren't likely to increase substantially through 2300. However, rising sea levels could mean that floods of 7.4 feet or more that struck the New York city area roughly once every 500 years before 1800, and which occur roughly every 25 years now, could happen once every five years between 2030 and 2045. The study expects about 5 inches to 11 inches of sea-level rise likely in New York City between 2000 and 2030. (On the other coast, rising seas could swamp the headquarters of tech firms in the not-too-distant future.)