The killer storm that pummeled the East Monday and left the nation's largest city with a crippled transit system, widespread power outages and severe flooding has resurfaced the debate about how best to protect a city like New York against rising storm surges.
"Hurricane Sandy is a wake-up call to all of us in this city and on Long Island," Malcolm Bowman, professor of physical oceanography at State University of New York at Stony Brook, told NBC's Richard Engel, who surveyed the damage from a police helicopter Thursday. "That means designing and building storm surge barriers like many cities in Europe already have."
Bowman points to storm surge barrier projects in St. Petersburg, Russia, and in the Netherlands as models. In the Netherlands, a country where a considerable part of the population lives below sea level, such barriers help control flooding in some of the most densely populated areas.
"If we had such barriers in place during Hurricane Sandy there would have been no damage at all," Bowman said.
Before the storm, Mayor Michael Bloomberg's administration had said it was working to analyze natural risks and the effectiveness of various coast-protection techniques, including storm-surge barriers. But officials had noted that barriers were only one of many ideas, and they have often emphasized more modest, immediate steps the city has taken, such as installing floodgates at sewage plants and raising the ground level while redeveloping a low-lying area in Queens.
"It's a series of small interventions that cumulatively, over time, will take us to a more natural system" to deal with climate change and rising sea levels, Carter H. Strickland, the city's environmental commissioner, told The New York Times this summer.
Sandy sent a record 14-foot storm surge into New York Harbor, flooding subway tunnels and airports. It forced the closure of the stock market for two days, the first time that's happened for weather-related reasons since 1888. There's no estimate yet for the cost of the devastation in New York City, but forecasting firm IHS Global Insight put the cost of the damage along the coast at $20 billion, plus $10 billion to $30 billion in lost business.
Graeme Forsyth, an engineer for CH2M Hill in Glasgow, Scotland told The Associated Press that his firm's early-stage proposal for New York is a levee-like barrier that would stretch five miles from the Rockaway peninsula in Queens on Long Island to the Sandy Hook promontory in New Jersey. The barrier would stop a surge of 30 feet, twice the height from Sandy. Gaps would allow ships, river water and tides through, but movable gates could close off all of New York Bay from the Atlantic when necessary. The barrier would protect most of the city, with the exception of Rockaway itself. It would also shield parts of New Jersey.
An animation, produced by the Dutch company Arcadis, shows how a sea gate could protect New York Harbor when a storm surge is imminent. The gates would close and block the water from entering the harbor until the danger has passed.
"Some people may say that storm barriers are an extreme solution," Bowman told NBC News. "I just would say it's bold, it's imaginative, it's permanent in the sense that it could protect the city for another 150 years. The Europeans have done it, why can't we?"
Some scientists, however, say there needs to be a holistic approach and that barriers are only one part of the solution.
Cynthia Rosenzweig, a senior research scientist at the Goddard Institute for Space Studies at Columbia University, told NBC News that as the region rebuilds, developers must take into account rising sea levels.
"The better way is for New Yorkers to be smart from engineered solutions like tidal barriers, fixing the subways where they're vulnerable, fixing our sea walls, remaking our wetlands so that we can, across our whole region and for all our 21-and-a-half million people, protect against the next Hurricane Sandy," Rosenzweig said, adding that even the Dutch now admit they can't protect everyone with barriers.
In the wake of Sandy, Bloomberg, too, appeared skeptical.
"I don’t know that I think there’s any practical ways to build barriers in the oceans, when you have an enormous harbor like we do," he said in a press conference.
But for Bowman, the time to act is now.
"It's a question of national security. It's a question of survival. It's a question of the future population being able to live there so it's taken very, very seriously," he said.
The Associated Press contributed to this report.