There are valid reasons not to believe in AGW.

How could the puny activities of Man possibly affect the massive (and historically very stable) global climate machine?

Geological evidence shows that there have been many dramatic changes in global climate due to purely natural causes in the distant past. (Although they have manifested themselves over centuries and millennia, not decades.)

Scientific evidence is just as prone to fads, fashion, political and cultural (mis)interpretation as any other form of historical or journalistic information.

It is hard to accept that global mean temperature changes of only one or two degrees (even if they could be measured and accurately compared with past ages) could lead to the extreme changes being ascribed to modern climate change.

The greenhouse gas warming predicted by science is supposedly due to an increase in CO2 of only a few hundred parts per million. Even taking into account the doubling of CO2 concentrations we have unambiguously measured just in the last few decades, how can this possibly be?

I could go on…the long and short of it is that there is very good reason to be skeptical of the hypothesis that Man’s industrial and agricultural practices are causing severe and rapid changes to the Earth’s climate. Valid counter-arguments can be made to all the objections listed above, but they are nonetheless persuasive and must be fairly addressed. Besides, extraordinary claims require extraordinary evidence, and the burden of proof is always with those who are advancing a new paradigm. It always is good overall policy to be skeptical of new science, and demand strict adherence to scientific method and the rules of legal evidence. There is nothing wrong with being an AGW skeptic, in fact we need more of them. A valid point of view can be quickly undermined by over-enthusiastic and lazy supporters, true science will not suffer from honest and informed skepticism.

What IS wrong is the position and methods that have been adopted by contemporary AGW denialists. It is clear that their objections are not due to a healthy skepticism of the interpretation of evidence, it is motivated instead by ideological and political reasons, all of which can be traced back to the fact that whatever actions are taken to address the global warming problem will inevitably require policies that are threats to the profitability of business. It threatens their capacity to harvest profits, period, full stop, end of story.

All efforts to communicate or support the AGW position are attacked as unscientific, even when the earth sciences community is closer to unanymity on this issue than it is on any other topic. The skeptics have resorted to shameless cherry-picking, deliberate misinterpretation of evidence, manufactured biases, blatant lies, and an attempt to politicize the debate by blaming their opponents as socialists, traitors and foreign countries behind some vast conspiracy out to sabotage Western (or should I say?) American Capitalism. Although they have organized themselves in massive industrial organizations and lobbies mobilized for political and propaganda activity to combat any mitigation or policy which might threaten their class interest, they have accused the environmental and academic communities of being greedy “special interests” pursuing some evil economic agenda. When no trace of this agenda can be credibly demonstrated, it is claimed that it is an intricate conspiracy by Leftist professors and Liberal politicians to destroy free enterprise and provide themselves with research grants and support and (of course) RAISE TAXES. The organizations and methods used in this effort are reminiscent of the obstruction and resistance of every single past movement devoted to the public welfare (tobacco, carcinogens, pesticides, auto safety, food inspection, workers’ safety and employee rights) that has threatened corporate profit. Belief in global warming is now an anarchist plot, similar to the push for an eight hour day, or opposition to child labor, or tax-supported public education.

This is why I am always reporting on Arctic sea ice issues. The Arctic ice is the canary in the coal mine for global climate. The slightest changes show up here first, and most dramatically, and our technical means for monitoring it are most unambiguous and continuous. You can argue about how the data is interpreted, or what effect it will have on our future, but you cannot blame it on some Liberal conspiracy to falsify the pixel values coming from the satellites. And it is easily displayed in a form the non-specialist can easily understand and interpret, and compare with earlier measurements. You will note that in all the years the denialist trolls haunted this forum, and all the learned exposes they published on the Climatological Community Conspiracy, not once was the slightest effort made to attack the data.

Its not that the data was undeniable. NO data can ever be totally undeniable. Its just that they couldn’t come up with any convincing arguments to come against it. Now perhaps this is because the science has missed something. But I prefer to think that it was because they didn’t have the technical knowledge or intellectual integrity to come up with a convincing argument of their own.

They came to this site knowing this was a scientifically oriented community and that they needed to plant seeds of doubt here, among us, and among those non-technical audiences that came here to be educated on these issues. When they found out they couldn’t do this, they left. And as long as we continue to report on these issues here, with simple irrefutable raw data, they will stay away.