"The future of New Orleans looks bleak," says Ivor van Heerden, deputy director of LSU's Hurricane Center, who led the state's investigation of the Katrina disaster. "We have to recognize that global warming is part of our future, sea level rise is part of our future, more storms are part of our future. You flood those houses one more time, nobody is going to come back. And the rest of the country will lose interest."

For the moment, the city's prospects have brightened a little. Some of the 110 billion dollars in federal reconstruction funds is starting to trickle into homeowners' hands, and with the rebuilding plan issued in March the city finally has a blueprint for repairing its infrastructure and sparking a revival. The state has passed its first building code ever to help storm-proof future homes, while the fractious levee boards have merged into two state entities. The Corps of Engineers has 5.7 billion dollars to beef up the city's hurricane defenses and is releasing a long-awaited, supercomputer-generated, flood risk analysis that will help it craft a new hurricane-protection and coastal-restoration plan. Congress even gave the state a slice of oil and gas royalties from a new swath of the deep Gulf recently opened to drilling—to be used to restore the rapidly eroding wetlands, coastline, and barrier islands, which might one day provide some protection from future storms.

Torbjörn Törnqvist, a Dutch coastal geologist now at Tulane, is a rare scientist who is bullish about the future, seeing New Orleans' struggles with rising seas and stronger storms as a preview of what other coastal cities will soon face. He envisions a new urban landscape perfectly adapted to climate change, with restored wetlands, high-tech floodgates similar to those in the Netherlands, and a cleaner, greener, denser city. The entire pre-Katrina population, he contends, could live quite comfortably in the parts of the city that did not flood, transforming warehouses and blighted districts into new walkable, sustainable neighborhoods on the high ground.

"The situation here is a huge opportunity for the city and the nation," says Törnqvist, who says he can't imagine Holland turning its back on Amsterdam, or Italy giving up on Venice. "If we walk away, we'll miss a fantastic opportunity to learn things that will be useful in Miami, or Boston, or New York in 50 years." That kind of revival, however, would require a massive infusion of federal help, better engineering than ever before, and more social and urban planning than regulation-loathing Louisianans have ever stomached.

But even if wind and water give the Big Easy a respite until the corps can guarantee legitimate 1-in-100-year hurricane protection, powerful social and demographic forces unleashed by Katrina may already be undermining the city's revival. Researchers have found that major disasters tend to accelerate existing social and economic trends. A booming San Francisco rebuilt bigger and better after its 1906 earthquake and fire; while the decaying industrial city of Tangshan, China, needed a huge infusion of aid from the government to recover after a giant earthquake in 1976—and was ultimately saved by the country's burgeoning economy. It's a sobering precedent for New Orleans, which has been plagued for decades by economic decline—just a single Fortune 500 company is still headquartered there—shrinking population, failing schools, and high crime.

"So why protect it? Why protect a piece of history that's a cross between Williamsburg and Sodom and Gomorrah?" Oliver Houck sat in his office, hands locked behind his head, pondering the question on everyone's mind. "There are people who will fight to the death to stay here because it's such a damned joy to live here."

But at what price? Houck paused for a moment to gaze out his window at the oak-strewn Tulane campus. The university lost two departments and a quarter of its students to Katrina, while he and his family spent months in exile after the storm. "If two words characterize all of southern Louisiana now, they would be 'total uncertainty,' " Houck says. "It's the total talk around the table. It's the conversation you're having with friends and spouses, even strangers. What do we do now?"