News•November 2, 2015

New York Prepares for Up to 6 Feet of Sea Level Rise

LaGuardia Airport is about to be rebuilt in New York City, but by the end of the century, fish could be swimming where airplanes once parked at the terminal. That’s because sea levels in the area could rise by as much as 6 feet over the next 75 years, according to new predictions released by the state of New York.

The flooded Battery Park Tunnel in New York City following Hurricane Sandy in October 2012. Credit: Timothy Krause/flickr

New York State environment officials announced Friday that they’re creating new sea level rise regulations that will help coastal communities build more resilient homes and other buildings that will be better able to withstand storm surges and other flooding made worse by rising seas driven by climate change.

The new regulations will require developers in New York City, along Long Island and on the shores of the Hudson River to prepare for sea levels that could rise between 15 and 75 inches by 2100. At the far end of that scale, many of the areas hit hard by Hurricane Sandy — the Rockaway Peninsula and the shores of Staten Island, for example — could be underwater.

In addition to increasing temperatures and more frequent extreme weather, rising seas are expected to be among the most destructive effects of climate change. If greenhouse gas emissions are left unchecked, most of the U.S. population could be affected by rising seas, submerging some of America’s most famous icons, such as Wall Street, New Orleans and the Everglades.

About 500,000 people live on the 120 square miles of land that lie less than 6 feet above the mean high tide line in the state of New York. More than $100 billion in property value exists in that area.

The sea level rise projections were created as part of New York’s Community Risk and Resiliency Act of 2014, which requires the state to set official sea level rise projections for the end of the century. It also requires many building permit applicants to consider future flooding risks posed by rising seas.

The sea level rise range the state uses comes from a study conducted by Cornell and Columbia universities and Hunter College showing that rapid melting of the Greenland and Antarctic ice sheets could raise sea levels much faster and much higher than previously expected.

The study projects that sea levels could rise between 15 and 72 inches at Montauk Point on the eastern edge of Long Island, and between 15 and 75 inches in New York City. The level of the Hudson River near Albany, more than 150 miles inland from New York Harbor, could rise by up to 71 inches.

Cynthia Rosenzweig, study co-author and senior research scientist at the NASA Goddard Institute for Space Studies and Columbia University's Center for Climate Systems Research, said the state’s use of the study ensures consistency between resilience planning at both the state and city levels because New York City’s climate change panel is using the same methods to determine the threat from sea level rise.

“The New York State sea level rise projections, developed using state-of-the-science methods, will provide the best available climate risk information for decision makers throughout the state,” she said.

Daniel Zarrilli, director of the New York City Mayor’s Office of Recovery and Resiliency, said in a statement that accurate science is critical to effective climate adaptation.

“These coordinated projections, which also inform the city’s investments, will support critical work of making investments in climate adaptation and resiliency across the entire state,” he said.