2. How do we know the 97% agree?
To elaborate, how was that proven?
Almost no one who refers to the 97% has any idea, but the basic way it works is that a researcher reviews a lot of scholarly papers and classifies them by how many agree with a certain position.
Unfortunately, in the case of 97% of climate scientists agreeing that human beings are the main cause of warming, the researchers have engaged in egregious misconduct.
One of the main papers behind the 97 percent claim is authored by John Cook, who runs the popular website
SkepticalScience.com, a virtual encyclopedia of arguments trying to defend predictions of catastrophic climate change from all challenges.
Here is Cook’s summary of his paper: “Cook et al. (2013) found that over 97 percent [of papers he surveyed] endorsed the view that the Earth is warming up and human emissions of greenhouse gases are the main cause.”
This is a fairly clear statement—97 percent of the papers surveyed endorsed the view that man-made greenhouse gases were the main cause—main in common usage meaning more than 50 percent.
But even a quick scan of the paper reveals that this is not the case. Cook is able to demonstrate only that a relative handful endorse “the view that the Earth is warming up and human emissions of greenhouse gases are the main cause.” Cook calls this “explicit endorsement with quantification” (quantification meaning 50 percent or more). The problem is, only a small percentage of the papers fall into this category; Cook does not say what percentage, but when the study was publicly challenged by economist David Friedman, one observer calculated that only 1.6 percent explicitly stated that man-made greenhouse gases caused at least 50 percent of global warming.
Where did most of the 97 percent come from, then? Cook had created a category called “explicit endorsement without quantification”—that is, papers in which the author, by Cook’s admission, did not say whether 1 percent or 50 percent or 100 percent of the warming was caused by man. He had also created a category called “implicit endorsement,” for papers that imply (but don’t say) that there is some man-made global warming and don’t quantify it. In other words, he created two categories that he labeled as endorsing a view that they most certainly didn’t.
The 97 percent claim is a deliberate misrepresentation designed to intimidate the public—and numerous scientists whose papers were classified by Cook
protested:
“Cook survey included 10 of my 122 eligible papers. 5/10 were rated incorrectly. 4/5 were rated as endorse rather than neutral.”
