Two-thirds of the papers that Cook and his colleagues examined expressed no view at all on the consensus. Of the remaining 34%, the authors claimed that 33% endorsed the consensus. Divide 33 by 34 and you get 97%. But this result is essentially meaningless, because they set the bar so low.
The survey authors didn’t ask if climate change was dangerous or “manmade”. They only asked if a given paper accepted that humans have some effect on the climate, which as already noted is uncontroversial. It could mean as little as accepting the “urban heat island” effect.
So a far better question would be: How many of the studies claimed that humans have caused most of the observed global warming? And oddly, we do know. Because buried in the authors’ data was the answer: A mere 64 out of nearly 12,000 papers! That’s not 97%, it’s one half of one percent. It’s one in 200.
And it gets worse. In a follow-up study[1], climatologist David Legates read those 64 papers and found that a third of them didn’t even say what Cook and his team claimed. Only 41 actually endorsed the view that global warming is mostly manmade. And we still haven’t got to it being “dangerous”. That part of the survey results was simply invented, by politicians and activists.
Other researchers have condemned the Cook study on other grounds too. For instance economist Richard Tol showed[2] that over three-quarters of the papers counted as endorsing even the weak consensus actually said nothing at all on the subject. And evidence later emerged[3] that the authors of the paper were drafting press releases about their findings before they even started doing the research, which indicates an alarming level not of warming or of consensus but of bias.
The advice has been written and uttered in various forms for millennia.
> If the quote stated "If you are ignorant on a topic it's better not to discuss it" that would be advise. (Though less quippy).
Your quote would be different advice; it doesn't have the same meaning nor implications.
> But I read the quote as essentially saying: "You are so incredibly stupid you should never, ever attempt to speak to another human being ever again, on any conceivable subject".
How many of your personal experiences are you reading into a context-free aphorism of the ages? Friendly suggestion: you may be making this same mistake when interpreting words in other situations.