New York City had warnings that, given a strong enough storm, parts of the city faced serious flooding. Superstorm Sandy made those predictions come true.
Now, city officials and the federal government are talking about what they can do to prevent that sort of flooding in the future. Climate researchers project that sea levels will rise substantially in coming decades and storms could become more severe as ocean waters get warmer. In other words, New York City — and many other coastal communities, for that matter — is at risk of future coastal flooding, just like the kind that's wreaking havoc in Manhattan.
Climate change is real and its effects, existing and predicted, need to be addressed. Yes, there are costs associated with adapting to the changes. A New York Times article says that a storm surge barrier to protect New York City could cost in excess of $10 billion.
But there are costs to inaction as well. State Comptroller Tom DiNapoli estimates that Sandy could result in $15 billion to $18 billion worth of "economic loss" for New York. And that's just from one storm in one year. The true cost won't be known for a while.