Someday, the new Second Avenue subway line in Manhattan could help save a good chunk of New York City from going under water. The world's oceans, you may have heard, are rising, probably because the atmosphere is warming as it becomes more saturated with carbon dioxide from the burning of fossil fuels.

Soon enough, coastlines, not least New York's, could be swallowed by the breakers as they creep inland, perhaps by as much as 3 feet between now and 2100, as some models suggest. Even sooner, storm surges from monster hurricanes could drive water up 20 feet over the doorways of Tribeca, just as one did in New Orleans—if the predictions of the world's leading climate scientists are true, and unless somebody starts thinking our way around such a mess.

The engineer and Princeton professor Guy Nordenson has started thinking, and not in small steps, about how to avert this particular disaster in New York and, perhaps, other coastal cities. This month, a research team Nordenson leads is scheduled to release in book form its master strategy for keeping New York dry as the oceans gradually rise or suddenly rebel in storms. The project, titled "On the Water," won the 2007 Latrobe Prize, a $100,000 research award from the AIA, and it seems as audacious as it does plausible.

Hurricane Ike approaches the Texas coast in September. Look for increasingly erratic weather as the 21st century progresses.

Hurricane Ike approaches the Texas coast in September. Look for increasingly erratic weather as the 21st century progresses.

Credit: AP Images

Nordenson and his team looked at the New York—New Jersey Upper Bay, as bracketed by the Bayonne Bridge on the west, the Holland Tunnel and the Manhattan Bridge on the north, and the Verrazano Narrows Bridge on the south. Around the edges of Jersey City and Red Hook in Brooklyn, they propose a "softer" shoreline of sloped, fingerlike piers, extending out from what are now hard, vertical seawalls, that could help tame storm waves and enhance the tidal ecology. They also considered ways to blunt the impact of rising tides and surges by baffling the water's energy across a new series of islands, shoals, and reefs in the middle of the bay (shipping channels would stay where they are). That's where the Second Avenue subway comes in.

The Nordenson plan works with the city more or less as it exists, based in a deeply practical reality. It proposes to create islands, mudflats, and new shoreline transplants within caissons by using up to 40 million cubic yards of dredged material from the Port Authority's Harbor Deepening project and also the cutaway earth that will come from the Second Avenue line. New York subway cars themselves could be submerged to become reefs, as they have elsewhere. On a nice day, the grand composition would become a kind of aquatic parkland connecting the boroughs.

It's a proposal worthy of Frederick Law Olmsted, with supercomputers thrown in. "One of the things we're trying to do is marry rigorous science with the urban design proposal," Nordenson says. He has been working alongside Princeton colleagues who are involved with the United Nations' Intergovernmental Panel on Climate Change, using their modeling capabilities to "design" hurricanes and storm surges with geographic information systems and computational fluid dynamics to find the best way to keep the city's friendship with water intact.

"We're not going to get permission tomorrow to build islands in the middle of the bay," Nordenson concedes, "but we're trying to promote ways of thinking about this problem."

If anyone has different ideas, it's time to speak up. Architects need to start thinking about the problem, or others will think about it for them. In an issue of Harvard Design Magazine last year, Kristina Hill and Jonathan Barnett wrote an essay that described the vast challenges of addressing rising waters in coastal environments. Beyond the obvious but largely unheeded suggestion that we should avoid development on shorelines, most resounding in their analysis was that the greatest consciousness about the built environment in the face of rising seas and extreme weather was coming not from architecture and planning, but from the insurance industry. They noted that Allstate, for one, has been cutting its coverage of properties in some coastal areas, and that large groups of insurers' shareholders want insurers to keep close tabs on the risks related to climate change when they write policies. Insurance companies are "likely to increasingly shift the costs of sea-level rise and more damaging storm patterns to governments and individuals," Hill and Barnett wrote. More encouragingly, some companies, they added, "are also looking farther into the future and are influencing builders and other market agents to do more to mitigate climate change."

Underwriters and their shareholders have seen the data. Scientists in the journal Nature reported earlier this year that hurricane frequency rose by 40 percent between 1996 and 2005, likely owing to a 0.9 F rise in ocean temperatures. A warming atmosphere is believed to be causing more intense tornadoes (like the one that leveled Greensburg, Kansas, in the spring of 2007), relentless floods in some places and, in others, droughts that lead to forest fires. Development near the coasts and within danger zones inland has been driven largely by profit but, unless decent design solutions arise, will increasingly be driven by loss.

Amazingly enough, though, considering the sloth with which any industry moves without obvious gains ahead, it has taken only about 15 years for the idea of sustainability to pervade mainstream architecture. In 1993, the Congress for the New Urbanism and the U.S. Green Building Council both formed (coincidentally, but perhaps not) and changed the conversation about sprawl, transit, open space, sustainable materials, macroeconomics, and human health. Now architects and designers can be seen leading the way toward more environmentally sound buildings and infrastructure, and the message has caught on among the keepers of architecture's purse—namely, developers and financiers—and trickled into the public consciousness. Americans haven't yet achieved the ingrained eco-consciousness of your average European, but it's a very promising start for a culture bent on human dominion over all things.

It is not unthinkable that, in a similar time frame (or faster), architects, planners, and engineers could mobilize about the climate threat and design innovative defenses against it. For now, that job rests mainly with building code officials and ad hoc reponses to catastrophe, usually after the fact. Efforts in the building arts to mitigate environmental damage grow more sophisticated by the year, but reducing our collective carbon footprint will do only so much good when the issue unavoidably becomes one of trading our shoes for a pair of waders.