20 inches to disaster: U.S. coasts unprepared for higher seas

By Robert Lalasz
3 Jan 2012 Let’s say the rise in sea level that climate change will bring us — from melting ice caps and expanding seas — won’t be “all that bad” by, oh, the year 2080. Maybe … just half a meter (a little under 20 inches). We can deal with half a meter, right?

Well, yeah — if we’re ready to “deal with” almost 50 percent more affected people and 73 percent more property losses from a typical Category 3 hurricane — all because of the higher storm surge that’ll come from that additional 20 inches of sea level. (“Storm surge,” in case you don’t know, describes the ocean water that a storm’s winds bring ashore, in addition to what’s usually there with normal tides.) Those kinds of losses are the scenario the southern shores of Long Island, N.Y., are looking at, according to a new peer-reviewed study in the journal Natural Hazards. And it’s a scenario that could apply to lots of other U.S. coastlines, says Christine Shepard, the study’s lead author and a postdoctoral fellow with the Nature Conservancy’s Global Marine Team. Unfortunately, she adds, sea-level rise hasn’t been on the radar of most U.S. coastal planners until recently. So is there any good news? Yes, says Shepard: The study offers a set of approaches and accessible tools with which those coastal planners can start mapping their own communities’ vulnerabilities. (Are you listening, Islip, N.Y.?) I caught up with Shepard to find out more. […] Q. We’re talking about 20 inches of sea-level rise. (The height of an English Springer Spaniel, if that helps anyone visualize it.) Just how damaging could 20 inches be? A. Just a small amount of sea-level rise increases the damage — especially in areas with intense development and a high concentration of people and properties stretching from the coast inland, like the area of Long Island that we studied. Also, the damage per property increases with the depth of the water. Even just a slightly higher storm surge gives you more damage per property — you can really see these impacts at the town level. […]