CEDAR FALLS - "Ten thousand years ago, one storm changed the face of our planet. … It will happen again."

It's a phrase playing on television sets nationwide, touting the latest disaster film, "The Day After Tomorrow." Friday, moviegoers began pouring into theaters, eager to see the special-effects laden movie that portrays what would happen if a massive ice age struck Earth.

The film has added to the debate about the reality of global warming and its effect on the planet. Scientists fall on both sides of the issue.

Robert Balling Jr., a member of TechCentralStation.com's Science Roundtable and a professor at Arizona State University, has published more than 125 papers on global warming and other climate issues. Balling saw an advanced screening of the film and said audiences shouldn't expect true science.

"Scientifically it's as far from reality as you could get," he said. "Things freeze so quickly you can't believe it. The things happening in this movie would take decades or millennia to unfold, not days."

In the film, global warming causes an extreme change in ocean currents, which shuts down the Gulf Stream causing an ice age to cover North America in just 96 hours. "The Day After Tomorrow" could be called the mother of all disaster films, with giant hail stones, tornadoes, snow storms and earthquakes pummeling the planet.

"There is no evidence the great conveyor belt (Gulf Stream) has ever collapsed. It has not been shut down overnight," said Balling. "I would have to argue over the physics of the movie and how the events developed."

According to Balling, in the movie, cold air descends so quickly from the troposphere, it freezes everything. He said the event is a physical impossibility.

Thomas Hockey, a professor of astronomy at University of Northern Iowa, doesn't expect to see reality on a Hollywood movie screen.

"The interesting thing about so-called disaster movies is the rules of movie making and the rules of nature don't always coincide," said Hockey. "If you're searching for a disaster to depict, you have to find one on the right time scale. A lot of potential disasters take place over geologic time scales, and that's no good if you're introducing characters. Disasters have to fit a two-hour time block."

Despite the difficult task of fitting nature into an entertaining yet believable mold, Roy Spencer, a member of TechCentralStation.com's Science Roundtable and a principal research scientist for the University of Alabama in Huntsville, said Hollywood's fascination is understandable.

"Man versus nature has always been a great theme for stories, because man versus nature does happen. People do get killed in tornadoes and hurricanes," he said.

Balling said climate change on a global scale is nearly impossible. A catastrophic event of such proportions would most likely be in the form of a volcanic eruption.

"If you want a disaster that can happen, a massive volcanic eruption is one. That would be worldwide," agreed Hockey. "In the 1800s there was an eruption that killed 36,000 people. The skies were red for a couple of years."

Though Hockey believes Hollywood has no obligation to be realistic, he does see a problem with filmmakers labeling fiction as fact.

"The only trouble comes when they claim authenticity as a means to hype their product, and that authenticity is not deserved," said Hockey.

According to Spencer, the film's Web site is guilty of just that.

"The movie's Web site is an interesting mix of fact and fiction, so it makes the whole thing seem like fact," said Spencer, who cited articles on false weather accounts next to CNN and ABC news stories. "There's a story of a tornado in 1912 in Saskatchewan as evidence of global warming. There was no global warming in 1912."

Spencer cites interviews with director Roland Emmerich saying the world needs to unite and fight global warming as evidence Emmerich has bought into the idea of its catastrophic effect. But, said Spencer, there is a lot of conflict among scientists about how much warming there has been and will be.

"The public is already primed for severe global warming in the future, though the scientific view is pretty shaky," said Spencer. "I am willing to believe things are maybe about one degree warmer now than they were 100 years ago. But it's not at all clear what's due to human activity and what is just coming out of ice ages of centuries past. The climate is always changing, and we're always looking at changes as something we're causing. We're forgetting the environment does change itself."

Kenneth J. DeNault, an associate professor of geology at UNI, said what the Earth will do is unpredictable, but chances are humans will survive it.

"I have no crystal ball, but humans are incredibly adaptable. All sorts of things change up and down," said DeNault. "New Orleans is already under water. There have been a lot of Greek cities around the Mediterranean that have been under water and are dry again. It's part of living in a dynamic planet. If Earth were like Mars, it would be very inhospitable."

Both Balling and Spencer point out that the movie and Web site are incorrect in portraying a gigantic increase in severe weather over past years.

"There is no evidence that is happening right now," said Balling.

Maureen McCue, a doctor in preventive medicine and global health and a member of Physicians for Social Responsibility, disagrees. She cites evidence of massive global change.

"In other parts of the world there is in fact of all kinds of catastrophic events occurring. Island people are feeling we're drowning out their countries, and they have to move entire cultures and nations because of rising waters," she said. "What is being predicted is not gradual change but in a relatively short period of time, there will be very sudden and marked changes in climate and an increase in catastrophic events."

McCue believes humans do have an impact on the planet's climate, and cites a precautionary principle of PSR.

"If you have enough reason to believe your actions will bring a consequent threat, then you step back and say, 'I don't need to take that action,'" she said. "We know that putting more nitrogen or carbon dioxide into the air is contributing to changes in the atmosphere. We don't need to put those out, when there are less harmful forms of energy."

Worldwatch Institute, which assesses the interactions among environmental, social and economic trends, addresses the movie in detail on its Web site. It reads, "Rest assured, Earth's climate will never 'flip' in a matter of hours or days. Yet 'The Day After Tomorrow' brings attention to a real problem: climate change. Earth is warming at a faster rate than ever before in recorded history. Human activities like driving automobiles and burning coal are putting more and more heat-trapping gases - including carbon dioxide - into the atmosphere. These gases form a 'blanket' around Earth that is driving up global temperatures."

Liberal advocacy groups, like MoveOn.org, which counts former Vice President Al Gore and comedian Al Franken as members, are using the film to their political advantage and urging the Bush administration to support the Kyoto Protocol, a U.N. treaty that would require the United States to cut its carbon emissions 30 percent by 2012.

"The producers of this movie are seen as having a strong agenda pushing Kyoto with the message that we had all the scientific information before and didn't act," said Balling. "The theme closest to reality is that we could have acted and didn't, and 'we' is always the United States."

McCue is hopeful the movie will influence people to pay attention to environmental issues, but is leery of the possible negative effects of the film, as well.

"If nothing else a movie like this will hopefully be a starting point for discussion. I think it will put it in front of people's thinking more so than it is right now," said McCue. "If, on the other hand, it's just an action movie and people go for the special effects, then get back in their Hummers and drive back to their McMansions, we will have failed to send a message. It depends on how the movie is done. If it's so exaggerated it's unbelievable, then it will do nothing."

Alan Czarnetzki, an associate professor of meteorology at UNI, hopes "The Day After Tomorrow" portrays events as more right than wrong, and is optimistic the movie can make a difference in people's thinking.

"I think it has a great opportunity to raise public awareness about global climate change. It's entirely possible that parts of the world will see significant changes. It's within the range of possibility," he said.