When that happens, the researchers start arguing, long and sometimes hard, and continue arguing until one side or the other finds the missing or misunderstood data that tip the balance.

Scientific consensus happens when just about everybody agrees, which is exactly what is going on with global climate change.

Naomi Oreskes, of the University of California, San Diego, examined nearly 1,000 published papers on climate change. She found no disagreement within the scientific community on two questions: whether Earth's climate is warming and whether human activities are influencing that warming.

Not one, not a single paper, refuted the basic consensus statement that CO2 (carbon dioxide) is increasing, that it is changing the chemistry of the atmosphere, and it's having discernible effects, Oreskes told UPI's Climate.

Scientists also agree the CO2 increases are the result of human activity, she wrote in her paper, which was published in the Dec. 3 issue of the journal Science.

So the scientific consensus on climate change reported by the Intergovernmental Panel on Climate Change does, in fact, exist.

Oreskes, who is a history professor, said her results came about as a byproduct of research she was conducting on the process of scientific consensus.

I didn't do it to refute the contrarians, she said. That's kind of what came out of it, but what I was really interested in - what started the whole thing - was that I was doing a lecture for (the American Association for the Advancement of Science) on the question of consensus in science. It was not about climate change. It was about: 'If we are going to make a policy decision based on the best available science, how do we know the science is right?'

Oreskes said the history of science is full of examples where the scientists sometimes get it wrong, which was actually the intellectual question that I was looking at.

She said she chose climate change because there was a consensus claimed.

I'm a historian, she said, and one thing I know as a historian is that leaders are not always in touch with the rank-and-file. So it's a legitimate question to ask: 'Is there a possibility here that there is some disconnect between the leadership and the rank-and-file?' That's what motivated me to do this search of the database and to check that.

Oreskes said when she began the research: I didn't think I was doing any big deal. It just seemed like a little thing I was checking on the side ... So the point was just to do a little reality check between the consensus statements that have actually come out of the scientific societies ... and the IPCC, and what's actually in the literature.

She examined 928 peer-reviewed scientific papers and found not a single one - zero - contradicted the essential basic global-climate premise.

Not that the Oreskes paper will end the debate about a consensus. To the contrary, it has started its own round of uncivil discourse on the Internet and in the blogosphere. One critic called her a Stalinist, she said.

One thing I learned this past week based on the attacks I've received - some of which have been quite hostile - is that there is this whole kind of parallel universe on the Internet, Oreskes said. You can put anything on the Web.

She is trying to be philosophical about the firestorm she has created.

The fact that guy called me a Stalinist shows that he's a little desperate, Oreskes said. He doesn't have the facts on his side, so he's resorting to name-calling. That's a very old and dishonorable trick in American history, right? If you don't agree with somebody, you accuse them of being a communist.

The climate skeptics also have weighed in on the subject.

So far I have listed about 4,000 studies from 1972-2004, and about 10 percent disagree with the consensus position, said Timo H��meranta, the Finland-based moderator of a climate skeptics' Internet group.

Even a 10 percent diversion of opinion is not significant, rendering claims of a consensus still pretty strong.

While her arguments would seem to support the view that the consensus refers to 'serious global warming,' a careful reading reveals that it really refers to the rather benign (and even meaningless) conclusion that humans are influencing climate, said Roy Spencer, principal senior scientist at the University of Alabama-Huntsville.

Spencer, writing for the skeptic site Tech Central Station, said, Climate scientists will tell you that everything influences the climate, so what we really should be asking is, how much are humans influencing the climate, and is there anything we can and should do about it?

Referring to her Science article, Spencer said, Ms. Oreskes also makes a curious claim about past research on 'climate change': that of 928 climate research paper abstracts published from 1993-2003, none rejected the consensus view on climate change. While I doubt that I've read this many climate change papers, I do have several in my office that specifically state that quantitative estimates of global warming are not possible without further knowledge of certain elements of the climate system or that current climate models are overly sensitive.

Spencer called the consensus view mentioned by Oreskes in her article so qualitative and innocuous that few scientists would dispute it anyway.

On another Web site, RealClimate, Eric Steig, an isotope geochemist at the University of Washington in Seattle, countered: Undoubtedly some articles that have been published in the peer-reviewed literature that disagree with this position and that Oreskes's survey missed, but the fact that her sample didn't find them indicates that the number of them is very very small. One could debate whether overwhelming consensus is adequate grounds for action on climate change, but there are no grounds for debating whether such consensus actually exists.

There is a steady hue and cry in Washington to use good science in addressing many controversial issues, but there is usually little agreement on what constitutes that good science.

Oreskes' research may provide the catalyst for moving the climate debate away from the question of whether it is happening to what, if anything, should be done.

The level of agreement she found is rare in any field, but it is particularly scarce in science, where conflicting, strongly held opinions are the meat of existence.

There is no debate in the scientific community about the basic facts of this situation, Oreskes said. We have changed the chemistry of the atmosphere. We have a robust theory of radiative forcing. We expect it to have an effect on the heat balance. If we look for those effects, we see that they are taking place.

Climate is a weekly series by UPI examining the potential human impact on global climate change. E-mail [email protected]

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