A Consensus of Idiots

Most people have heard the claim there’s a 97% consensus on global warming. Most people probably couldn’t tell you what that consensus is. Is the consensus merely that global warming is real? If so, who cares?

Or is it what we’re told Barack Obama tweeted? John Cook, propietor of the website Skeptical Science, likes to talk about how happy he was when he found out, “President Obama tweeted our research to 31-million followers”? The tweet was:

But it wasn’t actually from Obama. It was just from a political advocacy group he allows to use his name. Also, if we click on the link the tweet provides, we find the study being referred to never said anything about global warming being dangerous.

If the consensus is so important Barack Obama should be talking about it, surely it should have a clear definition. Tom Curtis, contributor of Skeptical Science, claims it does. When asked about that study:

Please explain the conclusion of Cook et al. Does the paper claim that 97% of climate science papers endorse the assertion that >50% of recent warming has been caused by humans?

He answered:

It is only possible to pretend that it does not by assuming that the theory of AGW does not endorse that claim

According to Curtis, “the theory of AGW” asserts “>50% of recent warming has been caused by humans.” According to him, there was no doubt that was the argument the study was examining a consensus about. There wasn’t even doubt when scientists were asked about their views, says Curtis:

I should add to that that the idea that the respondents to the author survey were confused on what was being asked assumes them to be complete idiots who do not know what is at stake in surveys like this.

In other words, the only way people could be confused about what the consensus is is if they were “complete idiots. With that in mind, let’s remember the image I posted yesterday. The image shows the ratings done by the people participating in the study:


They seem to disagree quite a bit, and that’s after they went through an entire stage of the study where they talked to one another about their disagreements. If only idiots wouldn’t know what was being asked, why was there so much disagreement? Were the people doing the study idiots?

And if there was so much disagreement between the people performing the study, what can we expect amongst everyone else? Don’t we have to assume people not actively involved in the study would understand it less than those involved? If so, they must be even dumber.

5-9-2014 Edit: Replaced image with a properly scaled version.



  1. A legend would be pretty much impossible as there are 24 different raters displayed. Not only would that make a legend take up a huge amount of space, it’d be nearly impossible to distinguish most raters.

    For the rest, I can give a brief rundown for now. The x-axis shows the rating given to an abstract. The y-axis shows the percentage each value showed up in the individual raters’ ratings I didn’t label the percents, but you can tell what they are because the combined values for each rater have to add up to 100%. The size of each circle represents the number of ratings assigned by that rater to that value. (using a quadratic to get appropriate sizes.

    Anyway, I made this just so I had something to share right away. I plan on trying to make a better version of the image later on when I’ve had more time with the data. I had considered waiting a week or so before telling anyone about this material so I’d have time to work on things, but I decided I didn’t want to sit on it.

  2. Fascinating stuff, I look forward to you telling us more about your analysis and hopefully giving us some more breakdowns on the rater interpretations. I think if Cook doesn’t reply in say, ooh a week, you really should take his silence as his consent to reveal the full details. 😉

    I like your use of Curtis’s statement in the title. I had to read through that Curtis exchange a couple of times, and at first thought you may have been unfair to him i.e. that Curtis was just responding to the single claim that Cook et al does indeed *claim* that it shows a consensus that >50% of recent warming has been caused by humans – I agree it did *claim* that. But as seems typical with Curtis he can’t answer a simple question without trying to overload his answer with some other implications that he hasn’t earned the right to claim.

    I put this down to Curtis’s tendency for only fooling himself when cognitive dissonance threatens 😉 So it is clear Curtis consoles himself with the idea the survey was also ideally *designed* to elicit a consensus that >50% of recent warming has been caused by humans.

    …despite the clear criteria implicit in instructions for endorsement levels 1 and 7.

    I note a lot of the Cook et al defenders similarly hand wave about the “clear criteria implicit” in the instructions, as if assuming it is somehow a tacky layman trick to actually read the questions and instructions and think through what the paper was was actually *doing*. IMO This is where I think it is best shown to the layman how the paper falls down. Because all you have to do is know that the vast bulk of the 97% included rater and scientist respondents only assenting to this

    Implies humans are causing global warming. E.g., research assumes greenhouse gas emissions cause warming without explicitly stating humans are the cause

    This is clearly not “>50% of recent warming has been caused by humans”“, and there is clearly no reason in the survey instructions for even the self raters to play along with an implied game of knowing that Cook et al’s reputation “is at stake” 😉

    For me this is the weakest point of Cook et al and makes it a clearly risible “me too” paper that is hyped beyond justification. As you example above with the pathetic claim from the lead author that it has persuaded President Obama it somehow tells us 97% scientists are quaking about “dangerous” climate change is sheer self promotional spin. The worst science.

  3. In Tasmanian, during the last State election, a politician—Nick McKim, then leader of the Greens—repeated the lie, that 97% of scientists have endorsed the AGW conjecture, at a public meeting; my infuriated son, in pardonably strong language, asked him to stop lying; his school subsequently suspended him for three days.
    See “Unacceptable Language” and “Suspended for Denouncing Green Lies”.

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