Given the fire-storm of public ignorance over the weekend, I felt the need to go through what the EPA’s Pruitt actually said line by line and phrase by phrase, with commentary…
Transcript – CNBC’s Joe Kernen on 9th March 2017, interviewing Administrator Pruitt of the EPA:
Kernen: Do you believe that it’s been proven that CO2 is the primary control knob for climate?
Note here that Kernen is asking simply about “climate”. Not about ‘climate change’ or ‘man-made climate change’. Just about “climate.” with a full stop. “climate.” That’s all.
Nor did the questioner ask about ‘temperature’ or ‘temperate changes’. The phrase “primary control knob” is of course used and does imply “control” and thus change. But what the imperfect metaphor of the “control knob” means in the mind of the interviewer is left un-clarified. Of course it does have a specific meaning which can be implied from its use in some scientific papers and in the IPCC summary documentation (e.g. “Climate Change 2013: The Physical Science Basis: Working Group I”), where for instance the IPCC used it as a shorthand to mean that: C02 is the main initial or primary trigger which primes (“forces”) the overall ongoing process of global warming, albeit doing so alongside a number of other initial greenhouse gases such as methane and nitrous oxide, and after which the IPCC says C02’s warming effect is then greatly amplified via water vapour by a “typical factor between two and three”. (It’s a pity that the metaphor of a “knob” can be somewhat misleading to those outside the scientific debate, since normal people and journalists generally understand a “knob” to be something that is twisted to move heat up and down in precise increments to cause a very rapid and direct response. Like the oven control-knobs in your kitchen, for instance. This is why I feel that the metaphor is an imperfect one.)
Given the phrasing of the actual question he was posed, to the best of my knowledge this answer is scientifically accurate. In the overall ongoing global process of “climate” per se, CO2 is not “the primary control knob” driving “climate.” Remember, he was only asked about C02 in relation to “climate.” with a full-stop. Not about ‘climate change’ or ‘man-made climate change’. Nor was he asked about “man made C02”, just “C02”.
He then continued…
“I think that measuring with precision human activity on the climate is something very challenging to do and there’s tremendous disagreement about the degree of impact.”
So he’s immediately picked up that he’s only been asked about “the climate”, not about ‘man-made climate change’ or ‘dangerous climate change’ or a ‘future greenhouse effect’. As such, to the best of my knowledge, his answer is thus once again scientifically accurate. It’s also an accurate comment on the ongoing state of the scientific investigations around a host of uncertainties on the how different parts of the ongoing process fit together. For instance, it’s certainly been incredibly challenging to get NASA’s research planes to the correct parts of the upper troposphere, where key parts of the greenhouse warming process are thought to occur.
Similarly, it’s an incontrovertible statement to say that there is currently “tremendous disagreement” about “the degree of impact” of “human activity on the climate”. There is, even among scientists, and that measurements are being continually tweaked and revised up-and-down seems to amply display just one aspect of that “disagreement”. Again, remember that he wasn’t asked about ‘man-made climate change’, just about “climate.” But he’s addressing it using the phrase “human activity” — which I’d also note can cover all sorts of things, not just man-made CO2 emissions.
“So no, I would not agree that it is a primary contributor to the global warming that we see.”
Now he addresses CO2 specifically in the context of current measurable “global warming”, even though that wasn’t the question he was asked. Reflecting a key NASA paper he carefully uses the phrasing “primary contributor” to the actual “global warming that we see”. He is presumably well aware that while carbon dioxide is indeed the trigger, the “primary contributor” to the overall greenhouse effect is water vapour (~50% of the overall greenhouse effect, according to NASA) rather than the initial triggering carbon dioxide. At a water vapour effect level of ~50%, it is a basic and undeniable scientific fact that CO2 is not the “primary contributor” to the overall effect of global greenhouse warming that we can see happening. Again, in his answer he is not departing from the basic science.
Pruitt: But we don’t know that yet. As far as, we need to continue the debate and analysis.
Again, factually accurate if rather speculative. He might be leaving it open that that we might in future somehow discover that man-made C02 is the “primary contributor” to the overall global greenhouse warming effect, meaning more than water vapour is. However unlikely that may currently seem according to the physics.
Kernen: I agree, when I hear the science is settled, I never heard that science had gotten to a point where it was, I thought that’s the point of science, that you keep asking questions, but I don’t want to be called a denier, it scares me, it’s a terrible thing to be called. Administrator Pruitt I know you don’t want to be called that either. Um, thanks for being with us this morning.
Pruitt: Thank you very much.
So it’s interesting that Kernen appears sympathetic, and one then has to assume that he knew exactly what his careful phrasing of the question would allow Pruitt to say.