The science (of global warming) is not agreed upon. Simply saying it is so doesn't make it true.

Ignoring dissenting viewpoints - as many scientists and those in the media are attempting to do, is part of the problem.

But not ignoring dissent does not mean accepting any dissenting opinion that happens to come along, either. I agree that simply saying something is doesn't make it so. And apparently, the science of global warming is not agreed upon by everyone. However, among scientists who publish their results in peer-reviewed journals, there really isn't any debate.

But don't take my word for it - Naomi Oreskes had a short paper in a recent issue of Science in which she reports on her review of peer-reviewed climate science papers from 1993 to 2003. Her results are stark: Not a single peer-reviewed scientific paper challenged the consensus that climate change is being driven by human activities. Not a single one. She concludes: "Many details about climate interactions are not well understood, and there are ample grounds for continued research to provide a better basis for understanding climate dynamics. The question of what to do about climate change is also still open. But there is a scientific consensus on the reality of anthropogenic climate change. Climate scientists have repeatedly tried to make this clear. It is time for the rest of us to listen." Here's a link to her article.

But "60 accredited climate change experts" recently wrote an open letter to the Canadian Prime Minister arguing against the hypothresis of global warming. Here's a link to their letter.

How can this be? How can there be such a clear consensus in the literature, and yet, dissent from "60 accredited climate change experts" in an open letter? The answer's simple - firing off an open letter isn't the same as publishing research in a peer-reviewed journal. Moreover, although they claim to be "accredited experts in climate and related scientific disciplines" (emphasis added), many, such as Dr. Ross McKitrick, Associate Professor of Economics, University of Guelph, have rather tenuous claims to being "accredited climate change experts."

In fact, in the magazine Energy and Environment, Dr. McKitrick, along with his collegue Dr. McIntyre, claimed to have found "grave errors" in Dr. Michael Mann's "hockey stick" research, including calculation errors, data used twice, and a computer program that generated a "hockey stick" out of any data fed to it—even random data.

The science fiction author Michael Crichton took great delight in that the flaws in Mann’s work were not caught by climate scientists, but rather by outsiders — in this case, an economist and a mathematician. So which is it? Are they "accredited climate change experts" or are they outsiders? For their sake, I hope the latter, because when they tried their hand at the former, they didn't fare very well.

Crichton claimed that McIntyre and McKitrick had to go to great lengths to obtain the data from Mann's team, which obstructed them at every turn. But in any event, Crichton declared that McIntyre and McKitrick thoroughly discredited Mann and the whole "hockey stick" controversy, and that any continued reliance on the research was unwarranted.

Well, funny thing: it turns out that under testimony to the Senate Environment and Public Works Committee, each detail of the issues raised by Crichton, McIntyre and McKitrick was addressed, and Mann's data, methodologies and computer programs all turned out to be publicly accessible. Further, there was controversy about the type of "peer review" undertaken on the paper by McIntyre and McKitrick before its publication in Energy and Environment, as well as whether the alleged “errors” that they report are in fact real, and indeed whether the work of McIntyre and McKitrick was itself replicable.

"Observational evidence does not support today's computer climate models," the 60 scientists say, and Bob Carter, an Australian geologist and another signature on the open letter, goes even further by claiming that for the years 1998-2005 global average temperature did not increase, there was actually a slight decrease, "though not at a rate that differs significantly from zero."

Well, this is true only on the basis that 1998 was the hottest year ever on record, at least since 1890, and not surpassed until . . . 2005. Anything following the hottest year on record will seem like cooling trent by comparison. But the six hottest years on record have all occurred in the last eight years. After 2005, 1998 was the second warmest, followed by 2002, 2003 and 2004. And there's an important difference between 1998 and 2005: the strongest El Niño of the past 100 years lifted the average 1998 temperature, whereas the record warmth last year was not buoyed by such an effect.

So what observational data is not matching the models? It's one thing to write an opinion piece in the newspaper without providing any supporting data, or to shoot off an "open letter" to the Canadian Prime Minister, and it's a whole other thing to provide one's research, data and conclusions to scientific journals for rigorous peer review.

It's obvious that the letter from the "60 accredited climate change experts" is just good old Dr. McKitrick and his cronies playing tit-for-tat on a game they started, and frankly, at which they are faring rather poorly, as the rest of the scientific community remains unconvinced by their arguments and accepts the reality of the situation. So, while there's room for many points of view, some views are based on science, and others are based on, apparently, wishful thinking.