houses will have to be bulldozed. Right now, most of the homes in the city are uninhabitable.

Meffert faces a difficult task. Every time he goes to a house site here, he says, "It's one more knife in me that says, 'She did another one. She did another one,'" explains Meffert, "she" meaning Hurricane Katrina.

When you walk through these neighborhoods and you see the houses, you get a sense of the pain of the individual families. But you don't get a sense of what has happened to the city of New Orleans itself.

It is estimated that there were 200,000 homes in New Orleans, and 120,000 of them were damaged by the flood.

The part of the city known as the lower Ninth Ward received some of the heaviest flooding. The houses are splintered block after block after block, almost as if the city had been carpet-bombed in war.

Meffert says that before the storm, New Orleans had a population of 470,000-480,000 people. Realistically, he thinks that half of those residents won't be coming back.

The possessions of thousands of families, the stuff collected over lifetimes is suddenly garbage, clawed up into mountains in city parks. With so much gone already, should New Orleans pick up right where it was?

"We should be thinking about a gradual pullout of New Orleans, and starting to rebuild people's homes, businesses and industry in places that can last more than 80 years," says Tim Kusky, a professor of earth sciences at St. Louis University.

Kusky talks about a withdrawal of the city and explains that coastal erosion was thrown into fast forward by Katrina. He says by 2095, the coastline will pass the city and New Orleans will be what he calls a "fish bowl."

"Because New Orleans is going to be 15 to 18 feet below sea level, sitting off the coast of North America surrounded by a 50- to 100-foot-tall levee system to protect the city," explains Kusky.

He says the city will be completely surrounded by the Gulf of Mexico just 90 years from now.

Since this story aired on Nov. 20, there has been considerable discussion about whether New Orleans really is sinking, including on CBS News' blog, Public Eye.