For some people the global warming debate has gone as cold as these late March days; there isn't one anymore. But for two scientists scheduled to speak in Racine next week, it might as well be the heat of August.

Willie Soon, a physicist at the Harvard-Smithsonian Center for Astrophysics, and David Legates, an associate professor of climatology at the University of Delaware, don't buy into the prevailing hypothesis that all the carbon dioxide we're adding to the atmosphere will in just a few decades warm the earth and cause drastic changes in the weather.

Carbon no

For the first 14 of his 19 years in science, Soon said he conducted research on the sun without thinking about the role of carbon dioxide in the atmosphere, quietly publishing scientific papers that opposed mainstream thought on global warming. In the last five years, he said, his conscience drove him to start speaking out.

His work has led him to the conclusion that solar radiation, the sun shining on the earth, is the driving force in what other scientists believe is global warming. He suggests that the waxing and waning of the sun's power, as reflected in sunspot cycles, can account for changes in the global climate history.

Legates' objection to human-caused global warming lies with the lack of warming in the last decade. That suggests that some other force is acting on the climate, he said.

He is troubled by the computer models which don't reflect the real world, and he said that some of those predictive models assume extraordinary amounts of carbon dioxide because that's the only way the model will produce a trend.

Soon and Legates also take issue with the current scientific system. No one will truly engage him in discussion of the science, Soon said; everything descends into personal attacks.

"They're not willing to criticize my work and point out the errors. That's the problem. I don't know what is wrong with my argument," he said.

Legates said many scientists who don't necessarily agree with human-caused warming remain silent because it keeps research money flowing and because most want quiet lives.

Both suggested there is a problem of group-think in climate science. As the editor of a journal, Legates said, he could publish just about anything by picking the reviewers carefully.

"You can't simply can't declare the debate's over," Legates said. "We're not anywhere close to that point."

Carbon yes

"I think that skepticism is healthy in the scientific process," said Steve Vavrus, a senior scientist for climatic research at the Gaylord Nelson Institute of the University of Wisconsin-Madison. "I think it would be very dangerous if everyone had the same view and didn't question each other."

Although not an expert in solar radiation, he said he does keep up on the field and everything he's read discounts the sun as a force in global warming. Computer climate models are necessarily simplifications, and the large amounts of carbon dioxide used in them are not to find a trend but to account for all the other greenhouse gases, Vavrus said.

As to recent ups and downs, he said, there is always natural variability in the climate system.

If one just reads the science in the reports from the International Panel on Climate Change, he said, it's overwhelming. Likewise there are few naysayers at conferences because most scientists have come to the conclusion that carbon dioxide generated by humans is the major factor in global warming, he said.

What Soon describes as personal attacks are unfortunate, Vavrus said. "You know, I'd be interested in getting together with the two of them and having a beer and chatting about some of these things if we could keep it from getting personal, because I'm interested in their experiences in sticking their necks out and being such skeptics because I know it's such a tough road for them."

"On the other hand, scientists love to prove each other wrong," he said. That is so ingrained in scientists that it serves as a check on pressures to conform, he said.

If you go

What: Willie Soon of Harvard and David Legates of the University of Delaware discuss their view that carbon-dioxide emissions have little or nothing to do with global warming

When: Monday, 7 p.m., University of Wisconsin-Milwaukee, room W179 of the Student Union, 2200 E. Kenwood Blvd., Milwaukee.

- Tuesday, 7 p.m., Calvary Memorial Church, 4001 Washington Ave., Racine.