What Is Cook’s 97% Consensus? ‘Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming. This is a very wide definition that even most sceptical scientists would have little difficulty agreeing with. It is also an pretty meaningless statement’

By: - Climate DepotJuly 29, 2013 3:00 PM

What Is Cook’s Consensus?


By Paul Homewood
John Cook’s little paper, “Quantifying the consensus on anthropogenic global warming in the scientific literature” has attracted much attention in recent weeks.
Yesterday an essay by Brandon Shollenberger at WUWT, which accused the authors of “laundering lies”, made me realise that an important issue seems to have escaped our attention.
[As I say, much has been written on the subject, so bear with me if this particular issue has already been flagged up]

Brandon writes:-
It’s nothing but laundering lies. The authors don’t come out and directly say anything untrue, but they intentionally create and promote misunderstandings to inflate the importance of their work.
It’s rampant dishonesty hiding behind a fig leaf of deniability. This is how I recently described Cook et al’s PR campaign for their recent paper.
I didn’t intend to follow up on this comment, but this morning I saw a quote from Dana Nuccitelli that was impossible to resist:
We were always careful to say that while the survey involved 12,000 abstracts, the 97 percent consensus was among the ~4,000 abstracts that took a position on the cause of global warming (plus the roughly 1,400 of 2,100 self-rated papers taking a position). And we were careful to point out that the consensus was that ‘humans are causing global warming.

Nuccitelli says he and his co-authors always used a particular phrasing when describing their results.  I must admit, that is true.  They’ve always managed to say “humans cause global warming” with the implicit qualifier of “some” (that they knew nobody would pay attention to).  It’s obvious they knew the limitations of their results and didn’t want to be accused of lying.

Brandon is making the point that the 97% figure is calculated from the papers which acknowledge that “humans are causing global warming”, which could mean anything from a little to a lot. Indeed, this is exactly what Cook’s abstract says:-
Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming.
This is a very wide definition that even most sceptical scientists would have little difficulty agreeing with. It is also an pretty meaningless statement.
But does Cook really have this in mind when he talks of “endorsing the consensus”? The answer lies in the paper’s introduction, which states.
We examined a large sample of the scientific literature on global Climate Change, published over a 21 year period, in order to determine the level of scientific consensus that human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW).

So it now becomes totally clear what “consensus” Cook has in mind. It is essentially the IPCC one. Cook’s co-author, Mark Richardson, makes it even clearer, in this quote from the Institute of Physics:-
“We want our scientists to answer questions for us, and there are lots of exciting questions in climate science. One of them is: are we causing global warming? We found over 4000 studies written by 10 000 scientists that stated a position on this, and 97 per cent said that recent warming is mostly man made.”
The problem, of course, is that many of the papers analysed do not support this interpretation. Indeed, arguably the vast majority do not do so, as Cook’s own definitions of endorsement levels make clear.

All three of these categories are included in Cook’s claimed “endorsing of the consensus”. Of the 3896 papers that fall into these categories, 2934 are in the third one, and 934 in the second. I have gone into more detail on this issue here. But take a look at these three papers, which are included in category 3, because they give a good idea of how Cook’s claims are not backed up by the evidence.
[Cook provides a useful tool, which lists all the papers graded here. Have a play with it and you will see that there are very many other examples of such misrepresentation]
1) Buying Greenhouse Insurance
There have been numerous proposals for immediate cutbacks in CO2 emissions. Proponents argue that sizable reductions are necessary as a hedge against unacceptably rapid changes in climate. This paper provides a decision tree analysis of the problem. We examine how the optimal hedging strategy might vary with: a) the damage potential associated with the continued buildup of greenhouse gases; b) the accuracy and timing of climate research; and, c) the prospects for new supply and conservation technologies.

2) CO2 emissions reduction by price deregulation and fossil fuel taxation: A case study of Indonesia
As environmental issues, and the issue of global warming in particular, rise to the top of the international agenda, developing nations are faced with a major question: how to confront these environmental problems and simultaneously address a number of more pressing developmental imperatives? This paper tries to answer that question on a limited scale using Indonesia as a case study. The study indicates that by deregulating energy prices and imposing different levels of taxation on fossil fuels, Indonesia could reduce its CO2 emissions without considerably suppressing the growth of its economy. In the long run, however, these policies cannot cope with the inevitable rise in coal-use in Indonesia, due to constraints on domestic natural gas and oil resources. Limiting the growth of coal consumption in the future will require direct technological intervention in the supply and demand of energy and a shift in current energy export and import policies.

3) Effect of encapsulated calcium carbide on dinitrogen, nitrous oxide, methane, and carbon dioxide emissions from flooded rice
The efficiency of N use in flooded rice is usually low, chiefly due to gaseous losses. Emission of CH4, a gas implicated in global warming, can also be substantial in flooded rice. In a greenhouse study, the nitrification inhibitor encapsulated calcium carbide (a slow-release source of acetylene) was added with 75, 150, and 225 mg of 75 atom % 15N urea-N to flooded pots containing 18-day-old rice (Oryza sativa L.) plants. Urea treatments without calcium carbide were included as controls. After the application of encapsulated calcium carbide, 3.6 μg N2, 12.4 μg N2O-N, and 3.6 mg CH4 were emitted per pot in 30 days. Without calcium carbide, 3.0 mg N2, 22.8 μg N2O-N, and 39.0 mg CH4 per pot were emitted during the same period. The rate of N added had a positive effect on N2 and N2O emissions, but the effect on CH4 emissions varied with time. Carbon dioxide emissions were lower with encapsulated calcium carbide than without. The use of encapsulated calcium carbide appears effective in eliminating N2 losses, and in minimizing emissions of the “greenhouse gases” N2O and CH4 in flooded rice.
None of these papers remotely suggest that “human activity is very likely causing most of the current GW (anthropogenic global warming, or AGW).” (Nor for that matter are the authors qualified to give an opinion, and neither is any evidence provided).
So what are we left with? Cook makes assumptions about thousands of papers, that cannot be remotely justified on what their abstracts say. Worse still, his co-author goes on to make public statements that simply are not true.
This appears to be wilful misrepresentation on a large scale.