"That said, the skeptics have brought up some very, very interesting issues over the last few years. And they've forced us to think more and more about the data that we collect. We can owe the skeptics a vote of thanks for making our science as precise as it is today," says Mayewski.

One big supporter of climate science research is the Bush administration, spending $5 billion a year. But Mr. Bush refuses to sign a treaty forcing cuts in greenhouse gases.

The White House also declined 60 Minutes' request for an interview. Corell, who first studied the issue for President Reagan, believes the climate change facts are in, even if President Bush does not.

"When you look at the American government, which is saying essentially, 'Wait a minute. We need to study this some more. We can't flip our energy use overnight. It would hurt the economy.' When you hear that, what do you think?" Pelley asked.

"Well, what I do then is, I try to tell them exactly what we know scientifically. The science is, I believe, unassailable," says Corell. "I'm not arguing their policy, that's their business, how they deal with policy. But my job is to say, scientifically, shorten that time scale so that if you don't push out the effects of climate change into the long, long distant future. Because even under the best of circumstances, this natural system of a climate will continue to warm the planet for literally hundreds of years, no matter what we do."

Unit6 The Coal Cowboy

America's dependence on foreign oil - President Bush called it "an addiction" in his State of the Union address - has become a threat to the country's economy and security.

While the president spent much of last week promoting energy alternatives of the future, like hybrid cars and fuels made from wood chips, the governor of Montana, Brian Schweitzer, says there's something we can have up and running in the next five years.

What he has in mind is using the coal, billions of tons of it, under the high plains of his home state. The governor tells correspondent Lesley Stahl he wants to use an existing process to turn that coal into a synthetic liquid fuel, or synfuel.

The plan is controversial, but Gov. Schweitzer - half Renaissance man, half rodeo cowboy - seems ready for the challenge. In fact, he sounds like he's ready to take on the world.