NEW YORK First, life has to be rewound to Friday, Oct. 26 – the last weekday before Hurricane Sandy crippled and disoriented the New York area. To make that happen, repairs to damaged power grids, transportation networks and housing will grind on for weeks, if not months, at a staggering cost.

But the bigger question is what occurs after that.

Basic restoration leaves everything just as vulnerable to the next monster storm. Hurricane Sandy is now a gauge of the region’s new fragility. Climate change is presenting government – and the public – with some overwhelming choices.

Officials must ask whether it is sensible to replace buildings on the Manhattan waterfront, the Jersey Shore or the Long Island coast – and continue to dare nature. After all, the waters surrounding New York have been rising an inch a decade, and the pace is picking up.

In recent days, elected officials, including Gov. Andrew Cuomo, a Democrat, have warned that bold steps are needed, that to simply mop up is a fool’s errand. Experts agree.

“It’s a no-brainer for New York,” said J. David Rogers, a professor of geological engineering at the Missouri University of Science and Technology. “You’ve got such enormous assets and infrastructure that you want to protect.”

But, some experts also say that after rhythms return to normal, a no-longer-frazzled public may rebel if taxes and fees rise sharply to pay for better defenses.

The cost of the repairs alone will certainly reach tens of billions of dollars. Far-reaching solutions will cost many billions more. And the cost of not doing them, Rogers said, includes the threat that disrupted businesses might abandon an environment that feels unsafe. New Orleans, he noted, was the banking and insurance capital of the South until the great flood of 1927.

Few simple solutions

Robert Yaro, president of the Regional Plan Association, an independent urban research group, said the region should consider measures like storm barriers and sea gates, as well as better ways to seal transit stations, tunnels and utility plants against water.

Robert G. Bea, a professor of civil and environmental engineering at the University of California, Berkeley, said he was unimpressed by the aggressive plans trumpeted by some politicians, including those that call for a levee around New York. Some solutions could end up causing more problems, Bea said.

He said tightening and improving the current system might be more sensible than an enormous new system. “At least with the current system, you know where it’s weak,” he said.