Dec. 10, 2004  -- So often what you think you know may not be so. And it's a reason I love the book just out from America's top-selling thriller writer, Michael Crichton. He's the man who created the popular TV medical drama "ER," wrote "Jurassic Park," which ranks among the top 10 grossing films of all time, and much more.

Crichton's books and movies have grossed more than $4 billion. Now, he's tackling global warming in his latest techno-thriller, "State of Fear."

Crichton is an extraordinarily bright man. He paid his way through Harvard Medical School writing his thrillers. He told "20/20" he based "E.R." on what he witnessed as a med student at Harvard. "It was just experiences that I had had in the emergency room," Crichton said.

He says Anthony Edwards' and Noah Wiley's characters on "E.R." are based on him, describing them as "a little fumbling, not sure of themselves -- nice people."

When he wrote "The Andromeda Strain," the story of an organism from outer space that threatens to wipe out mankind, Hollywood came calling, and his medical career was over.

Ideas Ahead of Their Time

Thirty-five years later he is still meticulously melding fiction with cutting-edge science, which continues to open him up to criticism.

He was called anti-science when he wrote about the perils of manipulating DNA for cloning in "Jurassic Park." After writing "Disclosure," the story of a man who is sexually harassed by his female boss, he was labeled a sexist. But he was also prescient. At the time of "Jurassic Park," few people talked about cloning. Now it's often in the headlines. And sexual harassment of both women and men has been featured in newsmagazines.

Will he be similarly ahead of his time with his new book? "State of Fear" expresses skepticism of the claim that global warming is real and imminent.

The controversy the book is bound to stir up almost kept Crichton from writing the book. "I'm 62 years old. I've had a good life. I'm happy and I'm enjoying myself," he said. "I don't need any of the flak that would come from doing a book like this."

The tall and handsome Crichton -- he was once named one of People magazine's "50 Most Beautiful People" -- is a bit of a reluctant celebrity. "I don't really like to be in public at all. I get nervous. I sweat. My face gets red. I get flushed. I'm just not a public person, if I can help it. I mean I would never, ever appear in public if I could help it," he said.

Environmentalists Fomenting False Fears?

He spent three years researching "State of Fear." It's a thriller with footnotes, graphs and scientific references. In it he argues that the threat of global warming has been exaggerated by environmentalists.

"I'm saying that environmental organizations are fomenting false fears in order to promote agendas and raise money," he said.

In "State of Fear," environmental groups set off terrorist acts to focus attention on global warming.

Crichton agrees the Earth is getting warmer. But he says there is little to worry about because the climate is always changing and there is no evidence to determine if the changes are manmade or natural. In fact he says, climate scientists admit they can't predict what temperatures will be in 100 years.

"My view of this is that the media is like the guy going down the street with a sign that says 'The End of the World is Near,' and he picks a date and the day comes and goes, and the world doesn't end. So he doesn't stop with the sign. He goes home, makes another sign, puts a new date on it, and starts marching again. That's the way the media is," Crichton said.

He argues that researchers who study global warming often exaggerate the problem in order to get grants, often using celebrities to promote their cause.

By taking on global warming, Crichton hopes to ease some people's worries.

"I don't know what it is. We seem to be very ready to think it's all coming to an end. At least take in the possibility that actually everything might be going to be OK," he said.

Environmental Group Responds

In response to the use of its public service announcement in this "20/20's" segment, the Union of Concerned Scientists sent the following statement:

We hope Michael Crichton fans enjoy his new science-fiction thriller, while keeping in mind there is a very strong consensus among the vast majority of climate scientists that global warming is under way and human activity is a primary cause. Every time we drive a car, use electricity from coal-fired power plants, or heat our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the air.

Technologies exist today that can cut emissions of heat-trapping gases and make a real difference in the health of our planet. These changes often have other positive benefits such as improving air quality, saving consumers money, reducing our dependence on oil, and creating new jobs and business opportunities.

Our political and business leaders have a responsibility to help move us toward a cleaner energy future. Public investments should shift away from polluting fossil fuels to support for clean renewable energy such as wind and solar power, more fuel-efficient vehicles, and more energy-efficient technologies. People from all walks of life can play a role in slowing global warming by advocating for smarter government policies, better corporate practices, and informed consumer choices.