Bracing for Flooding in New York City
You might not think of New York as an island city, but that's what it is. New York City has close to 600 miles of coastline, and four of its five boroughs are on islands. All this makes New York especially prone to global warming’s most dramatic effects.
The city's boroughs are linked to each other and the mainland by about 80 bridges and tunnels. Most subway and tunnel entrances are only slightly above sea level, as are our three major airports. They are particularly vulnerable to rising seas and flooding from Northeasters and hurricanes.
Fiercer storms and higher sea level
Sea levels have been rising along the East Coast for thousands of years, in part because of the natural sinking of the land. But in the last several decades, scientists say, part of the rise can be attributed to global warming. Water at the Battery has risen more than a foot during the last century. Although sea levels in the New York area are projected to edge up several inches more by 2050, that's not what most worries experts.
For New York, a big problem is the combination of rising seas and stronger storms. Scientists predict that over the next century as the earth warms, weather extremes will become more frequent and storms more violent. Higher sea levels mean storm surges are likely to come further inland and do more damage. What's called a 100-year flood today could become twice or even four times more frequent.
On top of that, America's densest city is poised to grow by a million people over the next 25 years — putting even more people and property in jeopardy.
Crucial transportation system at risk
Storms that currently produce minor flooding could cause much worse destruction with higher sea levels. Our public transportation system, much like a human's circulatory system, is essential to the city's healthy functioning. It is the largest hub in the United States. Every day, subways, trains, tunnels, bridges and roads carry millions of people to and from work, to shops and entertainment all over the five boroughs and environs.
Frequent flooding could shut down subways, major roadways and airports, paralyzing the city and crippling business. A flooded transportation network would make evacuating the city next to impossible. To see why, one need only look at past flooding events.
Past storms are warnings of what's in store
In September 1999, tropical storm Floyd delivered 10 to 15 inches of rain in a single day, causing flash flooding in Manhattan and shutting down some commuter train lines because of downed trees, mudslides and flooding. A 1992 Northeaster overtopped airports and roadways. During that storm, the Hoboken, New Jersey PATH station, with floodwaters pouring down staircases and filling tracks, was so inundated that commuter service between New Jersey and New York City was interrupted for 10 days.
Today, some lanes on the FDR Drive are flooded during a heavy downpour and unusable for several hours. Given the disruptions that Northeasters bring, it doesn't take much to imagine a much stronger storm or hurricane closing down main arteries and the three airports. Even temporary closure of the airports, major hubs for domestic and international travel, wreak havoc on our air travel system.
What kind of damage can New York expect?
In the direst predictions, a Category 3 hurricane arriving at high tide could create storm surges that would inundate JFK Airport, LaGuardia Airport, the Lincoln Tunnel and more. Hurricane-force winds of more than 110 mph could shatter glass windows in skyscrapers, which are built to withstand winds only up to that.
Such a worst-case scenario could paralyze emergency rescue efforts and trap millions in Manhattan and the other boroughs, calling to mind the devastation to New Orleans wrought by Hurricane Katrina in 2005. In the case of a Katrina-sized hurricane, 2.2 million New Yorkers would have to be evacuated.
But even a less severe Category 2 hurricane could swamp the Holland Tunnel and shut down main highways like the FDR Drive and the Brooklyn Belt Parkway. (Get more details from Climate Change Information Resources web site.)
The region's dense development raises the stakes, too, when storms hit. Low-lying residential areas like the West Village, Battery Park City, Tribeca in Lower Manhattan, parts of Brooklyn, Queens and Staten Island are particularly at risk of storm surges and flooding. (See a map of flood evacuation zones [PDF] in New York City and the NYC Department of Buildings maps).
"I am proud to call New York City home, and I am raising two kids in the city. But we live in Lower Manhattan, and I am very concerned," says our Living Cities director Andy Darrell. "I want to leave a city for them that is the best it can possibly be."
No one wants the worst-case scenario to become a future reality, and we have the chance now to make the outcome very different. Each New Yorker can make small changes that add up to a big difference. (See a list.)
Sources
Hot Nights in the City: Global Warming, Sea Level Rise and the New York Metropolitan Region [PDF] (1999, Environmental Defense report).
Global warming, heat waves and unhealthy air [PDF] – Environmental Defense fact sheet
America's Flood Risk Is Heating Up: As Temperatures Rise, The Army Corps of Engineers Must Improve the Nations' Flood Control System" [PDF] (2007, Environmental Defense, National Wildlife Federation).
Climate Change: Reduce global warming emissions by more than 30% [PDF] from PlaNYC, New York City's new sustainability plan
Regional impacts: How Will Climate change Affect the New York Metropolitan Region? - Climate change Information Resources, New York Metropolitan Region, (Site accessed May 2007)
New York City Regional Heat Island Initiative – Center for Climate Systems Research: Climate Impacts Group (Site accessed May 2007)
The Real Riddle of Changing Weather: How Safe Is My Home? - The New York Times, March 11, 2007 (registration required).