Climate scientist Cynthia Rosenzweig has been studying the impacts of global warming on New York City since the 1990s, and was part of a group that analyzed the unique risks faced by the Big Apple way back in 2001. The group's report predicted what a once-a-century superstorm like Hurricane Sandy proved: the Brooklyn Battery Tunnel between major boroughs flooded, La Guardia Airport runways were underwater, and so on.

More recently Rosenzweig helped chair the New York City Panel on Climate Change, brought together to update the city on the latest climate science and to help city agencies prepare to adapt. The Mayor's Office calls such preparation "climate resilience"—and it got a trial during and after Hurricane Sandy as well as Hurricane Irene in 2011.

Scientific American spoke with Rosenzweig, head of the climate impacts group at the NASA Goddard Institute for Space Studies, while she prepared her Tarrytown home—threatened by trees listing in the wake of Sandy—for yet another northeaster storm.

[An edited transcript of the interview follows.]

Did you predict Superstorm Sandy's impacts, in some sense?
Sea-level rise and climate change were already on the radar screen in the New York metropolitan region way back in our [2001] report. In that report we have the critical elevations, the one-in-500-year projections for the [flooding] impact on the Brooklyn Battery Tunnel and all the La Guardia [airport] runways.

What could or should have been done differently to better prepare the metropolitan region for such a huge storm?
Virtually everything that happened [after Sandy] had been highlighted in our reports. What we're doing now is going over the science of Hurricane Sandy and identifying the scientific work that needs to be done. One [task] is this key issue of redefining the one-in-100-year storm. Everyone is saying: "What's up with this one-in-100-year storm happening every year?" But scientifically we still need to look at the data and address if there should be a change. Our reports have noted that the one-in-100-year storm is now one in 15 to 35 years, on the conservative end [not assuming rapid meltdown of glacial ice in Greenland and Antarctica].

Mayor Bloomberg had initiated a climate change adaptation task force with 40 agencies. New York City is one of the leaders in this country and even the world in setting up adaptation and assessing how climate risks are increasing. All of this had begun, but to have an event of this very large effect and impact—a one-in-a-multi-century storm—would be challenging for any city in its path. It's just that this was such a whammy. That's the nature of risk.

The [Metropolitan Transit Authority] had clearly learned how to shut down the subways [after Hurricane Irene in 2011]. It's not a complete surprise. It's almost a: "Yes, we've been learning about this, understanding that the risks are increasing and, in fact, now for sure they are."

Any loss of life is unacceptable [but] the loss of life and the damage would have been so much greater, think of it, if we hadn't had the evacuation plan in place and also closed the subways and the tunnels. It could have been far more devastating.

5 Comments

1. 1. drafter 11:11 AM 11/9/12

   In order to make the subway system impenetrable from ocean flooding would cost a fortune and would probably still leak so the best bet is often to let it flood and not use it for those few days. About dealing with the other surface waters from ocean flooding you can not build a drainage system big enough to deal with the onslaut so either make all the buildings 20 feet in the air to let the water flow or build dikes all around the city all are very expensive ideas. It might be better to just move.

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2. 2. BruceWMorlan 04:27 PM 11/9/12

   We clearly need to dissuade people from building and rebuilding in areas that we cannot protect from rising sea levels, or we need to wall out the sea and be prepared for local systems failures - like the Dutch. A simple way to accomplish this would be to stop subsidizing bad choices through subsidized flood insurance and unregulated banking. A well-regulated bank should be able to require insurance that is priced by free-markets, since a free-market insurance company should be charging premiums that reflect their exposure. Unfortunately, we tend to expect government to cover the costs of bad choices, and we tend to prevent banks and insurance companies from adequately covering their risks.

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3. 3. Sisko in reply to BruceWMorlan 04:16 PM 11/12/12

   Agreed

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4. 4. Sisko 04:50 PM 11/12/12

   Notice that nowhere is it suggested that mitigation activities will lessen any harm to cities.

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5. 5. Dr. Strangelove 08:40 PM 11/13/12

   New Yorkers should learn from the Dutch. Holland is below sea level. The Dutch literally drained the North Sea to reclaim a land area many times bigger than New York city. There is an old Dutch saying "God created the world, the Dutch made Holland."

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