New York City Is Getting Ready for Rising Sea Levels and Hotter Temperatures

While computer-generated visions of floodwaters sweeping across Wall Street and inundating Manhattan island have come to represent apocalyptic predictions of climate change, the reality is that it won't take an apocalypse for rising sea levels to threaten the integrity of the complex infrastructures that provide New York and the world's major coastal cities with water, sanitation, transportation, power, and communications.

Adapting to this reality has become a key part of future planning for London, Rotterdam, St. Petersburg, Tokyo, and Seattle, as well as low-lying cities across Asia. In New York City the effort has brought together scientists, government agencies and public and private utilities in an effort to comprehend the effects of climate change on a city with a 570-mile coastline and where 8.5 million people live only about 10 feet above sea level.

With only a foot and a half of sea level rise -- a realistic prediction for 2050 -- a storm as severe as Katrina could require New York City to evacuate as many as 3 million people. A three-foot rise in sea level -- which could well occur by the 2080s -- could turn major storms into minor apocalypses, inundating low-lying shore communities in Brooklyn, Queens, Staten Island, and Long Island; shutting down the city's metropolitan transportation system; flooding the highways that surround the city; and rendering the tunnels that lead into the city impassable.

And what if humankind continues to pump greenhouse gases into the atmosphere at the current, massive rate and the Greenland ice sheet and West Antarctic Ice Sheet melt faster than predicted, causing sea levels to rise as much as six feet or more? That, concluded a report released earlier this year by the New York City Panel on Climate Change (NPCC), "would place much of the city underwater -- and beyond the reach of any protective measures."

Modeled on the U.N.'s Intergovernmental Panel on Climate Change (IPCC), the NPCC's report is the first part of an effort to adapt the city's structures and infrastructures to future climate change. Under the co-chairmanship of researchers Cynthia Rosenzweig of NASA and Columbia University, and William Solecki of the City University of New York, the NPCC took the IPCC's global climate models and scaled them down to develop projections of future temperature, precipitation, and sea level rise.

Their not-surprising conclusion was that despite the city's -- and the world's -- efforts to implement reductions in greenhouse gas emissions and energy use, New York City would have to begin preparing now for the changes to come, to develop a "risk-based, cost-benefit" adaptation strategy that would increase the city's resilience to its changing climate, as well as give it the capacity to withstand the expected but unpredictable meteorological extremes.

While storm surges may be the most catastrophic threat, steadily rising temperatures may represent the most difficult challenge. Mean temperature in New York City may rise by two, five, or even as much as 7.5 degrees Fahrenheit by century's end and make the city's climate close to that of present-day Raleigh, N.C. The milder winters with few days below freezing and little snowfall -- just about the only good news in the report -- will be offset by long summers, with a third of the days above 90 degrees and marked by extended heat waves, frequent droughts, and more and more intense storms. By the end of the century, one-in-ten-year floods will come once every two to three years.

An Adaptation Task Force, made up of some 20 city departments, New York State and interstate authorities, and power and communications industries, has begun developing an inventory of infrastructures at risk. Working with local communities they hope to develop strategies -- from keeping development away from the waterfront, to maintaining sewer systems, to evacuation plans, to protecting waterfront neighborhoods.