The link is interesting. Late in the article it explains about sea ice melting. I'll say that sea ice melting does not raise sea level. Warming water does, though. Oysters reefs are not going to grow in many places. And I'm skeptical of marshes and islands helping New York much or being practical. The situation is different in Louisiana, where so much marshland was lost and is being lost that large areas are going from marsh to water. All that extra water makes less land between the Gulf of Mexico and New Orleans, so landfalling hurricanes (like Isaac this year) do not weaken as fast as they might have 100 years ago.

My grandfather (presumably among many others) opposed a plan (in the 50s or 60s?) to black the entrances of Narragansett Bay, Rhode Island with giant sea walls with gates in them. He pointed out that the currents due to tides in the narrow entrances would be really fast (can now be a couple of knots locally). Also, the Bay would become more polluted with reduced tides within, like New Bedford at the time, which does have a hurricane barrier.

I think you can't protect the New Jersey and Long Island New York barrier islands. Manhattan and some other places need to protect the subways and tunnels and electrical systems; there is another article on cnn.com about giant inflatable plugs for tunnels, already tested, but some sea walls may be needed.

Chris

• superstorms and sea level