Tom Brokaw is giving Al Gore some company in the effort to raise awareness of global warming.

The former NBC anchorman is host of "Global Warming: What You Need to Know," which doubles as an explainer and call to action for average Americans. It premieres 9 p.m. Sunday on the Discovery Channel.

Brokaw said he has seen and was impressed by "An Inconvenient Truth," Gore's documentary on the subject.

"It's the same science that we are drawing upon and it's irrefutable. ... To give credit to him, he's been on this issue for a long period of time," Brokaw said

Discovery, which has a partnership with NBC News, asked Brokaw last year if there were any projects he would like to work on.

He said he was interested in the environment, and Discovery mentioned its global-warming project, which it was making in partnership with the BBC.

Brokaw's wife, Meredith, is vice president of the environmental organization Conservation International.

They've traveled to some of the places featured in the Discovery documentary, such as Patagonia and Mongolia, and have seen firsthand the effects of global warming.

He's tried to alter some habits to save fossil fuels: changing light fixtures in his homes, for example. He owns a hybrid car, and so do both of his daughters.

"It's not affecting our lifestyle at all, not one whit," he said.

On the Discovery documentary, producers travel great distances to make the case that man has contributed to a rapid warming of the planet's atmosphere that has already had noticeable effects and will potentially have much more.

Most frightening are the scenarios that scientists can see for the future: increased sea levels swallowing cities like New York, more vicious hurricanes like Katrina, more land turning to desert. One expert even envisions half of the planet's species disappearing by the end of this century.

In helping put together the film, Brokaw said he was surprised at the speed with which everything is happening and the growing agreement among scientists about what was once a controversial notion.

Discovery does intend to alter one part of the film that, in a preview tape, talks about the United States' refusal to participate in the Kyoto international treaty to reduce greenhouse gases, he said.

Brokaw, 66, spoke by telephone from Colorado, where he's working on a documentary about illegal immigration. Another NBC documentary, abo ut the black underclass, is set to run later this month.

How's this retirement thing working out anyway?

"Good question," he said. "I flunked."