Andrew Montford: Meaningless Consensus On Climate Change
Contrary to reports, global warming studies don’t show 97% of scientists fear global warming
Apart from a handful of eccentrics, everyone believes in the reality of manmade climate change. That’s the message of a recent paper in the journal Environmental Research Letters, the latest in a series of similar efforts that have been used as a stick with which to beat policymakers. But scratch at the surface of any of these publications and you find that there is considerably less to them than meets the eye.
The earliest paper in this series, by Peter Doran and Maggie Kendall Zimmerman of the University of Illinois, reported the results of an opinion poll of climate scientists that Zimmerman had prepared for her MSc thesis. The headline conclusion – that 97% of climatologists thought that mankind was having a significant impact on the climate – was widely reported at the time.
However, although the survey was sent to over 10,000 scientists, there were actually only 79 responses from climatologists, so the 97% figure represented just 75 individuals. And what was not reported in the paper or in any of the ensuing publicity was that many participants were appalled by the survey and recorded their feelings at the time, calling it simplistic and biased, and suggesting that it was an attempt to provide support for a predetermined view.
A second paper, by William Anderegg and colleagues, took a rather different approach, dividing scientists into those who were “convinced” and “unconvinced” by the reports of the Intergovernmental Panel on Climate Change (IPCC) and then assessing their relative numbers and their scientific credentials. It was observed at the time that the authors appeared to be trying to create a handy blacklist of scientists non gratae, and so their conclusions – that 97% of scientists were “convinced” and that their expertise was greater than that of their “unconvinced” colleagues – were unsurprising.
But again, the problems with the paper were manifold. One of the authors explained on his blog (but not in the paper) that the list of “unconvinced” included some who were only there because they objected to the Kyoto approach to greenhouse gas reductions. Others observed that the list of “convinced” scientists included some who objected strongly to the IPCC’s take on climate change.
The latest paper, by John Cook and colleagues, made an extraordinary impact, having been mentioned thousands of times on the internet within hours of its release, and being cited on President Obama’s Twitter feed and by the U.K.’s Energy and Climate Change Secretary, Ed Davey. The authors of the new paper are all associated with the activist website Skeptical Science, and it is therefore perhaps unsurprising that the paper was written with the express purpose of making a political impact.
We know this because a security lapse at the Skeptical Science website led to its private discussion forum being exposed to public view. Among the threads was one in which the protagonists revealed that the purpose of the research was to demonstrate an overwhelming consensus on climate change.
It is also not surprising that some of the methodology was profoundly disturbing. The authors reviewed the abstracts of published climate papers to assess how much these could be said to be supportive of manmade climate change. However, Cook and his colleagues adopted a deliberately vague formulation of climate change, namely “humans are causing global warming.” This completely avoided the key question of the climate debate, namely “how much warming?”
In reality only a few scientific papers include a quantification of the manmade effect or the likely extent of future warming. A few more give a qualitative feel, but the vast majority take no position at all, being concerned with more mundane questions such as “what is the effect of mineral aerosols on the climate” or “how might climate change affect populations of natterjack toads.”
Most of these irrelevant papers were classified as implicitly accepting the IPCC consensus and it is small wonder then that the authors got the result they had set out to reach. This strange methodological choice did mean that the “consensus” category was very large, but also meant that it ended up including many papers by prominent global warming skeptics, a result that makes a mockery of the whole paper.
Once the methodology used by Cook and his colleagues is understood, it becomes abundantly clear that the consensus it describes is a very shallow one; the results add up to little more than “carbon dioxide is a greenhouse gas” and “mankind affects the climate.” These are propositions that almost everybody in the climate debate accepts; the argument continues to be over how much greenhouse gases have affected us in the past and how much they will affect us in the future, and whether any of this represents a problem.
However, while there is no consensus on these questions, in truth there should be. It is the very basis of the scientific method that data trumps hypothesis: as the Nobel laureate Richard Feynman put it, “It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiment, it’s wrong.” And a wealth of new empirical and semi-empirical evidence is now suggesting that any warming is likely to be far, far less than has been predicted by the vast electronic hypotheses that are the climate models.
Yet despite this, the IPCC and governments still cling forlornly to the models and their predictions of doom. It is almost as if they are worried about what might happen if climate change turns out to be less of a problem than they have led us to believe. But until they accept the scientific method, a true consensus on climate change will be elusive.
Andrew Montford is a writer and editor specializing in climate change. His briefing paper on the Cook et al study has recently been published by the London-based Global Warming Policy Foundation.