Especially significant was a tweet from Gavin Schmidt, a leading climate modeler at the NASA Goddard Institute, who for many years worked alongside James Hansen. “Groups perceived to be acting in bad faith should not be surprised that they are toxic within the science community,” Schmidt tweeted. “Changing that requires that they not act in bad faith and not be seen to be acting in bad faith.”

Evidently the right to practice and discuss climate science should be subject to a faith test. It is an extraordinarily revealing development. Fears about unbelievers’ polluting the discourse, as some academics put it, illustrate the weakness of climate science: The evidence for harmful anthropogenic global warming is not strong enough to stand up for itself.

Inadvertently Schmidt’s tweet demonstrates how far climate science has crossed the boundary deep into pseudo-science. Karl Popper observed of the trio of pseudo-sciences prevalent in 1920s Vienna that their followers could explain why non-believers rejected their manifest truths. For Marxists, it was because of their class interests. For subscribers to Freudian psychoanalysis and Alfred Adler’s psychology, non-belief was evidence of unanalyzed repressions crying out for treatment. So it is with climate science. Only the pure of heart should be allowed an opinion on it.