Mayor Michael Bloomberg's plan to protect New York City from future superstorm Sandys and other climate-related threats is the most ambitious and scientifically accurate plan of its kind in the world. But as global warming intensifies and sea levels rise, even this strategy may not be enough to flood-proof the city for very long, experts say.
The climate adaptation plan, unveiled last week, would funnel $19.5 billion into more than 250 initiatives to reduce the city's vulnerability to coastal flooding and storm surge. It comes eight months after Sandy engulfed 1,000 miles of the Atlantic coastline—delivering a 14-foot storm surge to New York and crippling the nation's financial capital. The storm showed just how unprepared New York and other coastal cities are to handle flooding from weather disasters.
"As bad as Sandy was, future storms could be even worse," Bloomberg said in a speech on June 11 at the Brooklyn Navy Yard, an industrial park severely damaged by nearly five feet of floodwater during Sandy. "In fact, because of rising temperatures and sea levels, even a storm that’s not as large as Sandy could, down the road, be even more destructive."
Roughly 20 percent of cities around the globe have developed adaptation strategies, according to a 2011 estimate by researchers at the Massachusetts Institute of Technology. But no other local government has pledged to spend more—and across so many different issue areas—than New York City, according to interviews with nearly a dozen experts on climate adaptation.
"I think it would be hard to be more comprehensive than New York," said Heather McGray, co-director of the vulnerability and adaptation initiative at the World Resources Institute.
New York's proposals are based on hyper-local climate models specific to the city using the most up-to-date science available. The models, which predict climate trends through the 2050s, were crunched by the New York City Panel on Climate Change (NPCC), an independent group of scientists and engineers established in 2008 as part of PlaNYC, the city's original sustainability and climate strategy.
"I would say that with this plan, New York City has confirmed its standing as a global leader on climate adaptation," said Radley Horton, a climate scientist at Columbia University's Earth Institute and the climate science lead for the panel.
Even so, Horton highlighted the plan's limits. "It's impossible to make any city fully resilient in the face of this inexorable rise in sea level," he said. Sea level rise in New York City has averaged 1.2 inches per decade since 1900, nearly twice the observed global rate. The NPCC estimates that in less than four decades the city's harbor could be 2.6 feet higher than it is today.
According to climate models, if countries don't quickly and drastically reduce their emissions by the 2050s, the earth's climate system will pass certain tipping points—such as the melting of the Greenland or Antarctic ice sheets—where climate change and its impacts will become unstoppable and irreversible.
Scientists are concerned that even the worst-case projections envisioned in Bloomberg's plan could be too conservative. That's because the model's projections stop in the 2050s, even though they will be used to develop construction guidelines for buildings that could stand in New York's floodplain for centuries.
"Look around," said Klaus Jacob, a geophysicist at Columbia University and a NPCC member. "New York City is filled with buildings and systems that were put in place 100-plus years ago. This means that whatever projects are being proposed will be around for a long time."
Jacob thinks the city's climate adaptation projects should be designed to handle climate conditions far worse than even the NPCC's most severe estimates, particularly on sea level rise. The panel is currently extending its projections through 2100, though it's unclear how the Bloomberg administration will use them since it has already published its recovery plan.
Philip Orton, a physical oceanographer at the Steven Institute of Technology in Hoboken, N.J. who worked on the NPCC report, also question Mayor Bloomberg's assertion during the plan’s unveiling that "as New Yorkers, we cannot and will not abandon our waterfront ... We must protect it, not retreat from it."
"At some point, I suspect we'll have to abandon at least some areas," said Orton, whose opinion is shared by Jacob. "There'll be no other choice."