I'm not quite sure when I first heard about how a hurricane like Katrina could destroy New Orleans; I know it was at least a few years ago. Mike Tidwell wrote a book about it in 2003: Bayou Farewell: The Rich Life and Tragic Death of Louisiana's Cajun Coast. No one paid much attention to the book then, but since Katrina struck, he's been on "Meet the Press", CNN (three times), Fox, MSNBC, CBS, and NPR. He says, "[M]y main objective in all of these interviews is to raise awareness of how climate change will soon turn every coastal city in the world into a New Orleans unless we make a rapid switch to clean, renewable energy."
Since he pretty much hit it on the nose before, sounds like it might be a good idea to listen to him now, no? Read his essay, which makes clear just how much of the Katrina tragedy was a result of poor environmental policy, here.