"These are extreme weather patterns. The frequency has been increasing,” he said.
Of protections like levees in Lower Manhattan, Cuomo said, "It is something we’re going to have to start thinking about … The construction of this city did not anticipate these kinds of situations. We are only a few feet above sea level."
"I don't know how practical it is to put gates on PATH tubes and subway tunnels," Bloomberg said in a separate press conference. "What is clear is that the storms we've experienced in the last year or so around this country and around the world are much more severe than before. Whether that's global warming or what, I don't know, but we'll have to address those issues."
Although levees or other storm surge barriers might sound like fantasy to some, there are proposals on the table for introducing barriers across New York's harbor or in the East River. Implementing them would cost at least billions of dollars -- but infrastructure experts said the time to prepare for climate change is now, not after disasters.
Klaus Jacob, a climate expert at Columbia University, warned months ago that a major flood could result in $58 billion in economic damages from a large storm surge. An event on something like that scale appears to have come to pass.
As the country found out with Hurricane Katrina, Jacob said, a little investment now can go a long way when the worst occurs.
"The price tag for [Katrina] was $100 billion," Jacob told The Huffington Post. If more money had been spent on levees and other flood defenses, "for $10 billion you could have prevented the problem."
Such storm surges are an issue of "nationwide consequence because it affects all the large cities on the coast," said Jacob. From New York to Houston, almost every major metropolis is threatened by extreme weather.
Because of climate change, he said, "even on a clear day a hundred years from now, the water will be where it is today under storm surge conditions. Which means, any storm surge from a normal any-old-storm could flood the subway unless we do something."
Even setting aside the issue of climate change, engineers say the country is doing far too little to strengthen its water infrastructure. The American Society of Civil Engineers has suggested that by 2020 the U.S. will face an $84.4 billion gap between what it is spending and what it should be spending on pipes, storm sewers and water treatment facilities. When storms come, underinvestment can lead to flooded streets or toxic discharges.
Robert Puentes, a senior fellow with the Brookings Institution's Metropolitan Policy Program, said he doubted the subways would have been better prepared if the Metropolitan Transportation Authority were more fully funded, because the need for simple day-to-day repairs is so great that the expense for more unusual events like hurricanes would still go unmet.
But he and others agree that the country is not doing enough to prepare its infrastructure for events like Sandy.
"Since we keep seeing large scale storms -- the derecho this summer, Irene, Isabel -- it may be wise for transit and infrastructure planners and officials to think of these as part of a new normal," said Puentes.
Comments like Cuomo and Bloomberg's mark a rare departure from U.S. leaders' usual silence on climate change. The fingerprints of global warming are all over storms like Sandy, the largest ever recorded in the Atlantic. Nevertheless, neither Mitt Romney nor Obama have been eager to talk about how they would address climate change. Romney even mocked the idea that we might try to halt rising sea levels at the Republican National Convention.
Of climate change's potentially far-reaching effects, Jacob said, "I think most people with common sense have understood it. The only people yet who haven't understand it are our politicians."