The second part of Mr. Perry’s statement is, as it happens, just false: the scientific consensus about man-made global warming — which includes 97 percent to 98 percent of researchers in the field, according to the National Academy of Sciences — is getting stronger, not weaker, as the evidence for climate change just keeps mounting.

In fact, if you follow climate science at all you know that the main development over the past few years has been growing concern that projections of future climate are underestimating the likely amount of warming. Warnings that we may face civilization-threatening temperature change by the end of the century, once considered outlandish, are now coming out of mainstream research groups…

I could point out that Mr. Perry is buying into a truly crazy conspiracy theory, which asserts that thousands of scientists all around the world are on the take, with not one willing to break the code of silence. I could also point out that multiple investigations into charges of intellectual malpractice on the part of climate scientists have ended up exonerating the accused researchers of all accusations. But never mind: Mr. Perry and those who think like him know what they want to believe, and their response to anyone who contradicts them is to start a witch hunt.