Most of America's urban infrastructure is coastal. Of the 25 most densely populated U.S. cities, 23 are along a coast. And two of the biggest threats from climate change are increasingly intense storms and rising sea levels.
The seas already rose some 7 inches during the 20th century, according to the Intergovernmental Panel on Climate Change. The U.S. Environmental Protection Agency says in this century they'll rise three to seven times that, or possibly more.
That could make for a very wet Financial District, and the rest of the Big Apple's famed neighborhoods may not fare much better—New York City's coastline, stretching 530 miles, is longer than that of Miami, Boston, Los Angeles and San Francisco combined.
Exiting Mayor Mike Bloomberg's panel on climate change warned of the twin-headed monster of extreme heat and heavy downpours. It forecast 90-plus-degree days to triple by 2050, while days with more than 2 inches of rain will increase by nearly 70 percent. The mayor's panel forecast seas rising 31 inches by mid-century; other estimates predict a sea-level rise of 2 meters in the 21st century.
Big, theoretical numbers don't necessarily sway the public. A quarter of Americans—and half of Republicans—still deny climate change. With the devastation wrought by Sandy still fiercely evident more than a year later and hundreds of residents and business owners still trying to recover from its damage, could this superstorm have been the tangible, physical wake-up call that Americans needed?
(Read more: Many US watersheds failing stress test)
Marco Marani, a professor of civil and environmental engineering at Duke University, said yes. And projects are under way to protect our coastal infrastructure from the resulting stormier rising seas: everything from "horizontal levees" and floating communities to new oyster beds and restored tidal marshes.