Responses to the question: "Do you think human activity is a significant
contributing factor in changing mean global temperatures?" Image credit: Skeptical Science - data from Doran (2009)
"Science is not a democracy!", "Consensus means nothing!", "A majority once believed the Earth was flat."
From Brian's post on a huge survey showing scientific consensus on climate change to my post about holocaust denier and climate conspiracy theorist Nick Griffin, the refrain that scientific consensus is irrelevant has become a common meme from climate skeptics and denialists in recent weeks. But they're wrong. Here's why. Like all of the best half-truths, the fallacy that the overwhelming consensus in climate science "means nothing" has its roots in a real and important fact—namely that science is not a democracy, and evidence really is what counts. But what proponents of this idea miss is that this evidence is only valid to those who have the scientific background to properly assess that evidence in its appropriate context. Skeptics and denialists are right to argue that all it takes is one ground-breaking study to prove that man-made global warming is false, or even that it is all a 'hoax' that has been made up for fiendish purposes. Where that argument falls flat on its face, however, is that this ground-breaking study consistently fails to appear.
As commenter Houston so elegantly put it in a response on one of my posts, evidence leads to consensus. Scientists like nothing more than to disprove established theories and upset the status quo. The idea that scientists may be in possession of knowledge that would bring about the biggest scientific upset of recent history, and yet would simply sit on their hands because of peer pressure or grant funding is, quite frankly, ludicrous beyond belief to anyone who knows anything about the scientific establishment.
Yes, there are papers and articles floating about in the blogosphere questioning this data set or that particular graph, but time-and-time-again these papers are picked apart and discredited by fellow scientists. And if they are not, data sets are revised, research methods updated, and guess what? The consensus remains.
From amateur scientist Willis Eschenbach's accusations of data misrepresentation at Darwin Airport, which have been debunked as outright lies by the folks at ScienceBlog, to skeptic campaigner Richard Treadgold's similar accusations of manipulation in New Zealand, which was subsequently picked apart by the folks at HotTopicNZ, "smoking guns" consistently and repeatedly turn out to be damp squibs.
And let's not forget the idea that sunspots somehow account for climate variation, the evidence for which has been analyzed and discounted by Foukal et al in Nature, and key proponents for which seem to have trouble making their code available for analysis. (To date, I have not heard a cry of outrage from the skeptic camp at this refusal.)
The point is that each and every paper or article that comes out, peer-reviewed or not, has been thoroughly discussed and picked apart by scientists, clmatologists and lay-people alike. And still, the scientific consensus remains solid.
Yes, there are people out there who choose to believe the scattering of researchers who continue to dismiss AGW—and that is their prerogative. But given the fact that most of us know next to nothing about climate science, it is impossible for us to discuss the meaning of any one data set or other evidence in any meaningful way—let alone get a grasp on how the evidence that has been collected around the globe all points in the same direction.
In the end, all of us non-experts choose which side we believe. And just as a jury member will take into account both the credibility of each individual witness to a crime, and the consensus that forms from differing accounts, so too we observers need to exercise a healthy and rigorous analysis of what is being said, and by whom.
We rely on neuroscientists to discuss the controversies that occasionally spring up in their field, likewise evolutionary biologists. So too it takes the disciplined and extended learning of a climate scientist to understand climate science. Sure, there are people out there who will tell you AGW is bogus, just as there are people out there who will point to "research papers" debunking the idea of evolution, or that HIV is linked to AIDS. But for those claims to have any validity, they need to stand up not just in discussion with amateur scientists, angry bloggers and vested interests. They need to undergo the rigors of peer reviewed science.
And to those folks who argue that "climate gate" somehow proved the peer review process invalid, I ask you to show me how. To date, as far as I am aware, the worst that has come to light were some off-hand remarks that efforts would be made to keep two papers out of the IPCC report (both of which made it into the report—so if there was a conspiracy, it was an astoundingly unsuccessful one), and that CRU climatologists believed their colleagues should boycott a journal they considered to be practicing poor science. The editors of that journal later resigned because of the breakdown of the peer review process at that journal.
So by all means, send along your "proof" that man-made global warming is a fallacy in the comments below. But I'm a busy man, so entering into debate on each and every link posted is unlikely to happen—if you have a particularly compelling article or paper, it would be great if you can also post the credentials of the researchers, the forums in which it has appeared (peer reviewed or not), and why you think it has more credibility than, say, the National Research Council's Board on Atmospheric Sciences and Climate, NASA, or Wood and Steig's assessment of the CRU data.
In the meantime, please don't tell me that it means nothing that thousands upon thousands of educated experts around the world, from all political persuasions and backgrounds, continue to believe man-made climate change is a major issue, unless you can also tell me why you are better qualified to tell me what's really happening.