29 June 2009
New Orleans Doomed
Louisiana in 2100 (predicted)
About 10% of the land in Louisiana, including essentially all of New Orleans, will be underwater by 2100, due to subsiding delta silts and rising sea levels. The engineering effort necessary to make a big dent in this trend is mammoth. Much of New Orleans is already below or just barely above sea level, the state has lost a large share of its wetlands to the sea, and Hurricane Katrina cost the city about half of its population on a long term basis.
If the latest predictions by scientists are even partially correct, Katrina may be just the first significant blow of many to one of the nation's most historically and culturally rich cities.
UPDATE: Just to be clear, I bear no ill will for New Orleans, and indeed consider it one of the South's most interesting and worthwhile cities. The authors of the scientific journal article cited by the linked Science News article, at least one from a Louisiana university, no doubt earnestly want New Orleans to survive. And, disaster isn't imminent. The time horizon is for gradual (or more likely sporadic but unidirectional) loss of Louisiana's Gulf Coast over 91 years.
The point the science makes is pretty simple. Sea levels are steadily rising -- steps to stop global climate change and model corrections may impact the rate of sea level rise, but won't stop or reverse it. The Mississippi delta in the vicinity of Louisiana is also sinking, which makes Louisiana more hard hit than many other vulnerable sea level cities. Both the rising sea and sinking land are relentlessly making changes without reversing themselves, not cycling back and forth, at fairly predictable rates. Nothing conceivable is going to stop the sea level from rising or the delta from sinking at some rate. There have been major losses already which we have not stopped with engineering. The scale of the problem is enormous, comprising 10% of the land in Louisiana. The kind of efforts that are necessary for an even partial save of some of the Gulf Coast (perhaps perserving a string of access to Louisiana in the manner of the Florida Keys and saving New Orleans itself a la Venice or parts of the Netherlands) is an immense engineering undertaking.
My headline is hyperbole, of course. But, the point is serious. New Orleans is doomed unless someone does something to save it, and the steps that are necessary to do that on the scale that is really necessary (this report reveals that this scale is much greater than most people had previously assumed) haven't even been really put on the drawing board, let alone commenced in the long process of designing, cost estimating, funding, and building a world wonder class engineering project.
Can America and the world save New Orleans? It is possible. It will cost many billions of dollars. The Denver International Airport and Boston's Big Dig cost on the order of a billion dollars and then is a task orders of magnitude larger. It is likewise bigger than the task of building an aircraft carrier which costs about $15 billion. Forced to guess from the little that I know, I'd estimate that it would cost something on the order of the mid-hundred of billions to low trillions of dollars just to save New Orleans and a little strip of land to access it. No one that I've heard from has talked about that kind of major national investment yet.
Should the investment be made? I'm not even trying to get my hands around that question in this post. I'm simply pointing out a credible report passed on from a respectible scientific journal and explaining the threat it describes to one of our nation's oldest cities, then improving a sense of what would be involved to deal with it in this extended comment. Broad discussions armed with facts generally produce the best results. And, while locals may be most knowledgable about New Orleans' prospects, this problem is on a scale that it can solve on its own (nor can private industry).