Spread over the Cook et al 2018 paper are the terms “anthropogenic climate change” and “anthropogenic global warming”. It is also mentioned a in table S2 of the supplementary material. I assume that “anthropogenic global warming” means that global temperatures are rising and humans have an impact. This seems to be supported by the consensus claim from the paper (my emphasis):
There is an overwhelming scientific consensus that humans are causing global warming (Cook et al 2016), with a number of studies converging on 97% agreement among publishing climate scientists or relevant climate papers (Doran and Zimmerman 2009, Anderegg et al 2010, Cook et al 2013, Carlton et al 2015).
That is a far cry from the previous statement in the Alice in Wonderland paper. In that paper, the claim was made that there is a consensus that global warming “presents a global problem”. A claim that obviously was unsupported by the papers that were referenced.
At least he skipped the “dangerous” part of the claim. It is now in line with what the referenced papers researched. As explained in the link above, the referenced papers investigated the claim that global temperatures are rising and that humans have an influence in this. Not whether it is dangerous. Not whether something should be done about it.
However, I don’t think that the term “AGW” is used in this way in the paper. This sentence in the abstract makes me think that he means something different (my emphasis):
Misinformation can have significant societal consequences. For example, misinformation about climate change has confused the public and stalled support for mitigation policies.
This is not something surprising, I read similar claims in Cook’s previous papers. But this statement gives away that it is not just an objective observation that global temperatures are increasing and humans have something to do with it. This is going one step further, it assumes global temperatures are increasing because of humans AND is dangerous enough to support mitigation policies. More, it not only assumes that the effects will be negative, but also that the mitigation policies are able to decrease (or even reverse) these effects.
It is my impression that what is actually meant by “AGW” is more likely some gradation of CAGW (Catastrophic Anthropogenic Global Warming).
This makes the use of the undefined term “AGW” confusing. For example, when the authors claim that they are “refuting AGW”, do they mean they are refuting the claims that temperatures are not going up? Or do they refute the claims that increasing temperatures are not dangerous. If it is the former, then I could agree. If it is the former, I don’t know (there will be winners and losers).
In the same line: who are in fact those “denialists” who are central to this paper? Those who don’t believe in AGW? That would be a rather small list. Or those who don’t believe in the catastrophic aspect of AGW? That could be a large list.
It will also have consequences for the items in the S2 table of the supplementary data. For example, the first item in the table starts with following premise:
P1: There is no observed evidence for AGW.
Do they mean that “there is no observed evidence for a global temperature increase”? Or do they mean that “there is no observed evidence that those global temperatures will be dangerous”? Which are two different propositions. I would reject the first one (depending on the chosen time frame), but could lean towards the second one (dangerous compared to when or to whom?).
By the way, it is not only the term “AGW” that is not defined, the same could be said of the term “cause”. Do they mean that humans are “the only cause” of the warming? Or “the main cause” of the warming? Or cause “most” of the warming? Or “some” of the warming? Or just “any” warming?
Concluding, to me it is not really clear what the definition of “AGW” in the Cook et al paper is. That term is open to multiple interpretations and therefor could lead to a very confusing read: without a clear definition, it means whatever the reader thinks it means.
via Trust, yet verify
March 17, 2018 at 08:23AM
Iowa Climate Science Education 