The most intellectually dishonest argument that makes the rounds these days about climate change is the claim that "the debate is over" regarding the relationship between industrial greenhouse gas emissions and our recent spate of warming. It's infuriating because it has power. The enviro playbook is to avoid any detailed discussion of the science in the media - just repeat that phrase over and over, make some snide remark about how "skeptics" are either in deep denial or are simple lying hacks, and gut it out. And if you repeat something often enough, people begin to believe it.
The master of this sort of thing is Al Gore. A few days before the election, our uncredentialed scientist-in-chief was out on the campaign trail blasting away at every Republican he could find who had expressed doubts about the need for an anti-warming jihad. When in Seattle to beat-up on GOP Rep. Dave Reichert, who was running for the U.S. Senate (unsuccessfully, it turns out), he expressed incredulousness that Reichert was still unsure whether industrial emissions of greenhouse gas caused planetary warming.
"C'mon! And this man is a United States congressman? You know, 15 percent of people believe the moon landing was staged on some movie lot and a somewhat smaller number still believe the Earth is flat. They get together on Saturday night and party with the global-warming deniers."
That this sort of argument has power even with journalists on the warming beat is increasingly clear. NBC's chief science correspondant Robert Bazell, for instance, was asked on the air a few months ago by Brian Williams whether it was fair to say that the debate was over about whether industrial greenhouse gas emissions were warming the planet. Brazell answered that you could find someone who believes the earth is flat and put them together with another person and have a debate on it, but it would not be any more of a serious debate than the debate about industrial emissions and global warming.
Anyway, all of that is preface for an article that ran on election day in the "Science Times" section of the New York Times. Therein, you'll find an excellent story by reporter William Broad about a fascinating debate among geologists and paleoclimatologists about prehistoric (Phanerozoic to be specific) climate. Turns out that the planet once enjoyed super-elevated levels of CO2 (up to 18 times that of the present), but that it's very hard to detect elevated planetary temperatures from those high concentrations of greenhouse gases. It's unclear what this might mean, but the kicker is this:
"Carbon dioxide skeptics and others see the reconstructions [of prehistoric climate] of the last 15 years as increasingly reliable, posing fundamental quesitons about the claimed powers of carbon dioxide. Climatologists and policy makers, they say, need to ponder such complexities rather than trying to ignore or dismiss the unexpected findings. 'Some of the work has been quite meticulous,' Thure E. Cerling, an expert at the University of Utah on Phanerozoic climates, said. 'We are likely to learn something.'"
Honest scientists (of which there are suprisingly many - at least when they're talking to themselves) and honest environmental politicians (of which there are few) concede that there's a non-zero chance that the reigning consensus is wrong and that high concentrations of atmospheric carbon dioxide have far less impact on global temperatures than we think. In fact, that concession is made in multiple places in the four previous IPCC reports that have been published - the oft-cited "Bible" of consensus science on the matter. Broad's article suggests that there is in fact a greater possiblity that the present consensus is wrong than you would ever think if you read the other sections of the New York Times - or pretty much any other newspaper in the country, for that matter.