Scientific American has just re-posted an article from 2001
predicting what would happen if New Orleans got hit by a large hurricane. Here's a taste of the article.
The boxes are stacked eight feet high and line the walls of the large, windowless room. Inside them are new body bags, 10,000 in all. If a big, slow-moving hurricane crossed the Gulf of Mexico on the right track, it would drive a sea surge that would drown New Orleans under 20 feet of water. "As the water recedes," says Walter Maestri, a local emergency management director, "we expect to find a lot of dead bodies."
New Orleans is a disaster waiting to happen. The city lies below sea level, in a bowl bordered by levees that fend off Lake Pontchartrain to the north and the Mississippi River to the south and west. And because of a damning confluence of factors, the city is sinking further, putting it at increasing flood risk after even minor storms. The low-lying Mississippi Delta, which buffers the city from the gulf, is also rapidly disappearing. A year from now another 25 to 30 square miles of delta marsh--an area the size of Manhattan--will have vanished. An acre disappears every 24 minutes. Each loss gives a storm surge a clearer path to wash over the delta and pour into the bowl, trapping one million people inside and another million in surrounding communities. Extensive evacuation would be impossible because the surging water would cut off the few escape routes. Scientists at Louisiana State University (L.S.U.), who have modeled hundreds of possible storm tracks on advanced computers, predict that more than 100,000 people could die. The body bags wouldn't go very far.
A direct hit is inevitable. Large hurricanes come close every year. In 1965 Hurricane Betsy put parts of the city under eight feet of water. In 1992 monstrous Hurricane Andrew missed the city by only 100 miles. In 1998 Hurricane Georges veered east at the last moment but still caused billions of dollars of damage. At fault are natural processes that have been artificially accelerated by human tinkering--levying rivers, draining wetlands, dredging channels and cutting canals through marshes. Ironically, scientists and engineers say the only hope is more manipulation, although they don't necessarily agree on which proposed projects to pursue. Without intervention, experts at L.S.U. warn, the protective delta will be gone by 2090. The sunken city would sit directly on the sea--at best a troubled Venice, at worst a modern-day Atlantis.
As if the risk to human lives weren't enough, the potential drowning of New Orleans has serious economic and environmental consequences as well. Louisiana's coast produces one third of the country's seafood, one fifth of its oil and one quarter of its natural gas. It harbors 40 percent of the nation's coastal wetlands and provides wintering grounds for 70 percent of its migratory waterfowl. Facilities on the Mississippi River from New Orleans to Baton Rouge constitute the nation's largest port. And the delta fuels a unique element of America's psyche; it is the wellspring of jazz and blues, the source of everything Cajun and Creole, and the home of Mardi Gras. Thus far, however, Washington has turned down appeals for substantial aid.