NEW YORK: The warnings came, again and again.
For nearly a decade, scientists had told city and state officials that New York faced certain peril: rising sea levels, more frequent flooding and extreme weather patterns.
Daylight reveals Sandy's wrath
Americans woke to scenes of destruction wrought by monster storm Sandy after it smashed into the eastern United States.
The alarm bells grew louder after Tropical Storm Irene last year, when the city shut down its subway system and water rushed into the Rockaways and Lower Manhattan.
As New Yorkers woke to submerged neighbourhoods and water-soaked electrical equipment, officials took their first tentative steps towards considering huge infrastructure changes that could protect the city's fragile shores and 8 million residents from repeated disastrous damage.
Governor Andrew Cuomo said the state should consider a levee system or storm surge barriers and face up to the inadequacy of the existing protections.
''The construction of this city did not anticipate these kinds of situations. We are only a few feet above sea level,'' Mr Cuomo said during a radio interview.
''As soon as you breach the sides of Manhattan, you now have a whole infrastructure under the city that fills - the subway system, the foundations for buildings'' and the World Trade Centre site.
The Cuomo administration plans talks with city and federal officials about how to proceed. The task could be daunting, given fiscal realities: storm surge barriers, the huge sea gates that some scientists say would be the best protection against floods, could cost as much as $US10 billion.
But many experts say that given what happened with the latest storm, that inertia could be more expensive.
But a city-appointed scientific panel estimates that after rising about 2.5 centimetres per decade in the last century, coastal waters in New York are expected to rise as fast as 15 cms per decade, or 60 cms by mid-century. That much more water means the city's flood risk zones could expand in size.
Yasi more powerful than Sandy
Cyclone Yasi, which devastated north Queensland almost two years ago, had winds and storm surges "much worse" than hurricane Sandy, but the New York superstorm is twice as big.
''The city is extremely vulnerable to damaging storm surges just for its geography, and climate change is increasing that risk,'' the director of the sea level rise program at the research group Climate Central in Princeton, New Jersey, Dr Ben Strauss, said.
''Three of the top 10 highest floods at the Battery [southern New York] since 1900 happened in the last 2½ years. If that's not a wake-up call to take this seriously, I don't know what is.''
The dangers laid out by scientists as they tried to press public officials for change in recent years describes what happened this week: Subway tunnels filled with water, just as they had warned. Tens of thousands of people in Manhattan lost power. The city shut down.
What scientists, who have devoted years of research to the subject, fear most is that, as soon as the storm cleanup is over, the public will move on.
Mayor Michael Bloomberg is known worldwide for his broad environmental vision.
But one former official said it had been difficult to move from theoretical planning to concrete actions, and it was hoped that the storm this week would change that.
''A fair question to ask is, have we been as focused as we need to be for emergency preparations,'' said the former official, who spoke on condition of anonymity so as not to jeopardise ties to the administration.
''We've just been lucky. We need hardening for the risk we've always faced. Until things happen, people aren't willing to pay for it,'' the official said.
A state report on rising sea levels, issued on the last day of governor David Paterson's administration in 2010, suggested that erecting structural barriers to restrain floodwaters could be part of a broader approach, as well as relocating buildings and people farther from the coasts.
Mr Bloomberg, during a briefing on Tuesday, said that he was consumed with the task of getting the city going again and that it was too soon to determine what steps should be taken.
Under a proposal from the Storm Surge Research Group at New York's Stony Brook University in 2004, large portions of the city could be protected by three movable barriers installed at the upper end of the East River near the Throgs Neck Bridge, under the Verrazano-Narrows Bridge and at the mouth of the Arthur Kill channel between Staten Island and New Jersey.
Still, some experts consider the barriers a last resort and urge more modest changes, including subway floodgates.
After a deluge paralysed the subways for several hours in 2007, the transit agency spent $34 million on some flood protections. No additional state money has been forthcoming for an overhaul.
The New York Times