A non-sequitur or not a non-sequitur?

The subject of the second episode of the evidencesquared podcast mentioned in the previous post is among other “Scott Pruitt’s denial of the scientific consensus on human-caused global warming, both in a CNBC interview and in his hearing for head of the EPA”. At 03:57 in the podcast, the presenters start a audio excerpt of an interview of Scott Pruitt at CNBC back in 2017 when he was the head of the EPA (the interview at CNBC can be viewed here):

[Interviewer CNBC]
Do you believe that it has been proven that CO₂ is the primary control knob for climate? Do you believe that?

[Scott Pruitt]
No, I think that measuring with precision human activity on the climate is something very challenging to do. There is a tremendous disagreement about the degree of impact. So, no, I would not agree that it is a primary contributor to the global warming that we see.

[Interviewer CNBC]
Okay

[Scott Pruitt]
We don’t know that yet. As far as, we need to continue the review and the analysis.

This was the reaction that I didn’t expect:

[Peter Jacobs]
When I hear that…, what I hear is a bit like a non-sequitur. So the first part is like saying, like it is hard to measure and people are kind of going back and forth a bit on the actual amount of human influence, so therefor I don’t think that humans are -the interviewer said the control knob- the primary cause.

The first part of those two things are somewhat depends on, yeah, it is hard to measure the exact amount of human influence and like there is some discussion about the magnitude of impact. That does not lead into then the second half where he denies that humans are the primary driver of climate change, which is not exactly a controversial statement.

A non-sequitur is a conclusion that does not follow from the premises. It also is repeated later in the podcast in reaction to a similar statement made by Pruitt responding to the question of Bernie Sanders at the confirmation hearings (which was at the center of previous post):

[Scott Pruitt]
I believe that to be able to measure with precision the degree of human’s impact on the climate is subject of more debate than whether the climate is changing and our activity is contributing to that.

[…]

[Peter Jacobs]
Right, he is doing the thing that he does in CNBC interview where his is saying, there is some uncertainty about A therefor not B. That is not at all. That is a non-sequitur.

It was the non-sequitur statement that surprised me. When I heard the statements made by Pruitt, I didn’t have the impression that this was a non-sequitur. Jacobs considers the statement of Pruitt a non-sequitur because it is not possible to, on the one hand say that it is challenging to measure human influence on the climate, yet on the other hand being sure that humans can not the primary driver for climate change.

If the statement “I would not agree that it is a primary contributor” means that he agrees with certainty that CO₂ is not the primary contributor, then Jacobs has a point. But who says that the statement is made because he is sure? It as well could be that he made that statement because he is not sure about the level of human contribution (“control knob” as was said by the interviewer) and therefor refrains from speculating about the exact level. This is confirmed by repeating twice that he was not sure: “We don’t know that yet” and “We need to continue the review and the analysis”. To me that shows that he doesn’t feel he has sufficient information in order to pinpoint the exact level. That was how I understood this when listening to the interview.

The weird thing is that Pruitt actually:

• agreed that the climate is changing
• agreed that humans contribute to that
• even clearly stated (twice) that his issue is with the impacts (which both presenters acknowledged were not the subject of the consensus papers, including their own).

Although his position is in line with the investigated position in the Cook 2013 paper (see previous post), he was called out twice throughout the podcast for “denying the science”. In that paper, merely acknowledging the greenhouse effect was enough to get classified as endorsing the consensus. That is very different in this podcast in which he got judged on very different criteria.

Here we again see a fluid definition of what is the consensus:

• in the Cook 2013 paper the consensus position was measured as all those who acknowledged the greenhouse effect and agreed that humans have an influence on global warming
• in consensus communication to the public, the consensus position is considered as only those who agreed that the level of human influences is specifically higher than 50%.

I understand that it is the first definition that they investigated and found in the neighborhood of 97%, yet is is the second, not investigated, definition that Pruitt was evaluated against.

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