New Threat To Big Easy: Global Warming

The Army Corps of Engineers is rebuilding a stronger levee system in New Orleans after the devastation of Hurricane Katrina. But scientists now see something more dangerous than seasonal hurricanes: global warming.

"Sea level is rising worldwide, and that's going to have an immediate impact on New Orleans," Tulane University geoscientist Torbjorn Tornqvist told CBS News national correspondent Byron Pitts.

"It's all related to global warming. That's what's happening. We've seen in the past century, sea level is rising four times faster than in the preceding 1,000 years," Torngvist says.

Waleed Abdalati is a NASA career scientist, one of the Bush administration's top researchers on climate change.

"The state of the world's ice is that it's changing — and predominantly in most parts of the world, it's shrinking," says Abdalati.

One vivid example is NASA satellite pictures of the North Pole ice cap in summer. Since 1979, it has shrunk more than 25 percent.

"You could see an ice-free Arctic in the summer, where no sea-ice cover survives the summer melt. That could happen in the next 40 to 60 years," Abdalati says.

Places at risk for a sea-level rise range from the San Francisco Bay area to South Florida to the Chesapeake Bay.

Abdalati studied a Greenland glacier that lost nearly five miles in the last six years, and now it's flowing faster.

"It doubled its speed, just enhancing the amount of ice that is flowing or flushing out into the fjord and later, to the sea," Abdalati explains.

And that means higher sea levels for New Orleans.

"We have to push harder than anyone else in the United States to reverse the problem of global warming because we are facing that problem here first," Tornqvist says.

It's a scientific problem that may now be getting a political solution.