I include myself in this group. I have spent many hours reading as much of the literature on either side as I can, and come away, as it were, serially convinced: first by one side, then the other. Because, contrary to what one would absorb from the CRU emails, not all of the skeptics are yahoos. Though they are in the minority among climatologists, they include many eminent scientists, whose insights, whatever their field, cannot be ignored, raising as they do issues of scientific and statistical methodology that cross all disciplines. It is grotesque to lump nuanced skeptics like Freeman Dyson, perhaps the most celebrated physicist alive, in with creationists and 9/11 “truthers.”
But that does not resolve the dilemma. It is pleasing to lecture global warming advocates, as many have, that “science is never settled,” but it is not quite true. That the earth is round may once have been subject to dispute, but it would be ridiculous to suggest the same today. The issue is not whether scientific questions can ever be settled in principle, but whether the particular thesis of man-made global warming has reached that stage.
It is true there is a fever of unreason abroad. It draws on multiple sources—the relativism of the left, the anti-intellectualism of the right, the absolutism of fanatics of all stripes—and spreads, notoriously, via the Internet, with the illusion of expertise it provides. What is produced often has nothing to do with skepticism. To be a skeptic is to doubt something is true, not—as with many global warming “skeptics”—to declare with ex cathedra certainty that it is not.
But self-professed defenders of science should not fall into the trap of regarding every dissent from orthodoxy in the same light. There are two traps, actually: being too closed-minded, and too open. We are not obliged to give 9/11 truthers and other cranks a respectful hearing. Indeed we are obliged not to: we dishonour our worthy opponents if we treat our unworthy opponents with the same deference. But we do far worse when we dismiss eminent scientists who happen to fall outside the scientific consensus as lunatics or hired guns.
The error here is not only scientific. It is also political. If your desire is to persuade the unpersuaded among the general public, the very worst way to go about it is to advertise your bottomless contempt for your adversaries. That the IPCC scientists reacted in this way shows how unprepared they were, for all their activist enthusiasm, to enter the political arena.
When a new planet is found, its discoverers are treated with appropriate deference, even reverence. The latest theory of the origins of the universe may be the cause of some head-scratching among the general public, but not outright disbelief, even if it displaces what had previously been the prevailing view. Who are we to say?
But the same deference does not apply when science presumes to answer more political questions, though the gap between expert knowledge and the public’s may be no less wide. Who are we to say? Only the voters, that’s who. It is not enough to admonish the public to “listen to the experts.” Experts can get it wrong. Freud was once near-universal dogma. Today his theories have been largely discredited. Perhaps—who knows?—global warming will one day meet a similar fate.
How to distinguish, then, between genuine authority and mere received wisdom? Conversely, how do we tell crankish imperviousness to evidence from legitimate skepticism? Credentials, though hardly infallible, remain a good reference point, a means of weighing the credibility of sources. An impressive CV doesn’t make a bad argument right, of course, but with a problem of such baffling complexity as climate change, it can serve as a proxy for the uninitiated.