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Tuesday, May 15, 2012

Rick Piltz: Stephen Schneider climate science expert credibility in climate change

Interview with Stephen Schneider on climate science expert credibility study

Climate Science Watch talked with Stanford University Prof. Stephen Schneider about his co-authored article, “Expert Credibility in Climate Change,” published recently in Proceedings of the National Academy of Sciences. Dr. Schneider discussed the rationale and implications of the study and responded to several criticisms that have been raised. See Details for video and text from the interview.
UPDATE: Dr. Schneider passed away on July 19, 2010, en route to give yet another talk on climate change.
Post by Rick Piltz and Rebeka Ryvola
Earlier CSW post:
June 21: New study finds striking level of agreement among climate experts on anthropogenic climate change
“Expert Credibility in Climate Change,” a new study in Proceedings of the National Academy of Sciences, finds that 97-98% of climate researchers examined who are most actively publishing in the field support the IPCC conclusions, i.e., are convinced by the evidence for human-caused climate change, and that the relative climate expertise and scientific prominence of researchers questioning the findings is significantly below that of convinced researchers. The authors of this first-of-its-kind study used metrics of climate-specific expertise and overall scientific prominence to examine expert credibility among scientists who agree with or question the primary conclusions of the IPCC….
Stephen H. Schneider is the Melvin and Joan Lane Professor for Interdisciplinary Environmental Studies, Professor, Department of Biology, and Senior Fellow, Woods Institute for the Environment, at Stanford University.
The video contains portions of our July 8, 2010, interview with Prof. Schneider. The transcript below contains more extended text from the interview, in addition to what is included in the video.
From Stephen Schneider interview with Climate Science Watch director Rick Piltz, July 8, 2010:
CSW: The article on climate science expert credibility that you co-authored, recently published in the Proceedings of the National Academy of Sciences (PNAS) – what prompted this study?
Schneider: There are so many claims out there from all kinds of interests, about how climate change is ‘the end of the world,’ or ‘good for you,’ and people – policymakers and media – are understandably confused. Part of the problem is that over time the media has fired so many of its specialists that there aren’t a lot of people left to sort out the relative credibility of all the claims. So, since a lot of those people who deny that humans have any impact on climate are claiming that they have scientific expertise, we said let’s just put it to a test.
There’s a very well-known and widely used independent index, which is: how many papers have you published and how many times have people cited them in the scientific literature? Those people who chose to put themselves on lists and petitions denying that there was a human impact on climate, let’s see how many papers they’ve published, and how many citations they have. Those people associated with the Intergovernmental Panel on Climate Change (IPCC), let’s check them and see if there’s a difference.
CSW: In terms of how you defined the groups in the study, you have one category that you refer to as “convinced by the evidence” – convinced by the evidence for anthropogenic climate change. The other group is the “unconvinced by the evidence.” Are you defining them by scientific perspective, or are you defining them by policy positions?
Schneider: It’s a bit controversial how you define anyone in categories like “convinced” and “unconvinced” since none of us – I hope – are 100% convinced of anything, or 100% unconvinced, but we can have a vast preponderance of evidence. There are lists where groups have organized themselves into pro, basically, and con human impacts on climate. Most of the ‘pros’ work on the IPCC, mainstream science, and most of the ‘cons’ do not. Only two or three are in common. They wrote petitions saying they didn’t think there was much likelihood of anthropogenic change, and we put them in the unconvinced category. That is, they put themselves in the unconvinced category. As far as those who spent much of their life working at IPCC, there’s a very high probability they are convinced this problem is real or they wouldn’t be putting in all this time. The bottom line is that we let people self-define and then we let the numbers fall where they were, in terms of the relative credibility of each of those groups – and the credibility was vastly different. Not surprisingly, those people who do work daily in climate science have a much, much higher citation count and more published papers than those who just claim it isn’t true but really, for the most part, are not prime workers in climate change.
CSW: Well then, what about the charge that the study, in effect, is creating a ‘blacklist’ of certain scientists? It’s saying that these are the skeptics, the unconvinced by the evidence, but they don’t have any credibility and so you shouldn’t pay any attention to them.
Schneider: Well it’s laughable that it’s a blacklist. A blacklist is what somebody like Joe McCarthy did back in the 50’s, or Senator Inhofe is doing now, when we all know it’s the senator who is deliberately distorting. How could we be doing a blacklist when we’re using the names that they gave? All we did was test it. The fact that they don’t publish very much is not our issue. This is a fact check.
It really matters what your credentials are. If you have a heart arrhythmia as I do, and I also have a cardiologist, and you also have an oncological problem as I do, I’m not going to my cancer doc to ask him about my heart medicine and my cardiologist to ask about my chemo, I’m going to the experts. Who’s an expert really matters. People with no expertise, their opinion frankly does not matter on complex issues. And in my opinion shouldn’t even be quoted when we’re talking about the details of the science.
When we’re talking about what to do about it, then every citizen’s opinion is just as important as anybody else’s, and everybody should be quoted. But not about how many degrees of warming there is – that takes a lot of knowledge, to be able to know what you’re talking about. That knowledge is very well reflected in the counts of the number of times people’s scientific papers have been cited by their colleagues. That’s where the mainstream climate scientists have a major advantage over those who are unconvinced. We feel that’s a robust conclusion, that most of the claimants that there’s no anthropogenic climate change are very weak scientists – by and large – and most of their comments are really not very scientifically credible.
CSW: I believe Judith Curry argued that, on your various lists, under “convinced of the evidence” you were including people who are ecologists and biologists, and who aren’t really experts in the climate change detection and attribution research. So that somehow skews your notion of how to sort people out in terms of credibility. What’s your response to that?
Schneider: Well, there are two responses. First of all, there are a couple dozen people in the world that work in ecology – that includes people like Terry Root, Camille Parmesan, and myself, among others – who actually look at the bloom dates of roses in your grandmother’s back yard and when birds come back. We do detection and attribution studies. Those people are in the IPCC and they are legitimate experts and they have published research in Science and Nature and PNAS and places like that. There was an entire chapter on it in [IPCC] Working Group II and those people, again, like Cynthia Rosenzweig, were included in the IPCC database.
But she does have a point, that not everyone in IPCC is an expert in detection and attribution. That’s certainly true. But when she said that the IPCC group that we used in our PNAS study should be cut down to something like 20% of the original. That’s hundreds of people, that’s still quite a lot of people. If you look at the “unconvinced of evidence” group, virtually nobody in it has ever published a paper on detection and attribution. So, by Judy’s own logic, that means it’s virtually a null set. That means there’s almost nobody in the unconvinced category who has any expertise whatsoever in detection and attribution. So, if you take her logic, and apply it symmetrically to the “convinced” and “unconvinced” you narrow the “convinced” group down to a smaller but still clear and robust population and the “unconvinced” has virtually no expertise, and their opinion becomes completely irrelevant.

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