The more peer-reviewed papers a climatologist has published and the more often those papers are cited, the more likely it is that the researcher supports the science underpinning anthropogenic climate change (ACC). That’s the conclusion of a paper published this week in the Proceedings of the National Academy of Sciences.
This comes as absolutely no surprise to anyone working in or following the field. But scientists like to put numbers to things, and the paper, “Expert credibility in climate change” does a pretty good job of doing just that.
There’s a marvelous, interactive, graphical illustration of the data at Jim Prall’s website. (Click on the screen capture at right to get there.) Here’s the bottom line:
…97-98% of the climate researchers most actively publishing in the field support the tenets of ACC outlined by the Intergovernmental Panel on Climate Change, and (ii) the relative climate expertise and scientific prominence of the researchers unconvinced of ACC are substantially below that of the convinced researchers.
There are problems with oversimplifying the spectrum of opinion in any scientific subject. The four authors of the study, William R. L. Anderegg (Stanford), James W. Prall (U of Toronto), Jacob Harold (William and Flora Hewlett Foundation), and Stephen H. Schneider (Stanford), divided climate researchers into two groups, those convinced by the evidence that fossil-fuel emissions are heating the planet, and those unconvinced. The convinced group had far more papers and citations to their name than the unconvinced.
Some critics complain that this kind of dichotomy is misleading. Roger Pielke Jr. of the University of Colorado told the journal Science that “By putting scientists into two categories which do not reflect the subtleties of the debate, … this paper simply reinforces the pathological politicization of climate science in policy debate.” There’s some merit in that argument, but the paper’s conclusions address a critical problem: the insistence of many mainstream news outlets to treat each side with undeservedly equal levels of respect. As Schneider et al. write:
Despite media tendencies to present both sides in ACC debates, which can contribute to continued public misunderstanding regarding ACC, not all climate researchers are equal in scientific credibility and expertise in the climate system. This extensive analysis of the mainstream versus skeptical/contrarian researchers suggests a strong role for considering expert credibility in the relative weight of and attention to these groups of researchers in future discussions in media, policy, and public forums regarding anthropogenic climate change.
Among the paper’s strengths are the depth of analyses of the numbers. As Leo Hickman blogs at The Independent, you’d think that the numbers might be skewed in favor of older researchers, who have had more time to publish and be cited, if all else was equal.
From the ~60% of researchers where year of PhD. was available, mean year of receiving a PhD. for UE [unconvinced by the evidence] researchers was 1977, versus 1987 for CE [convinced by the evidence] researchers, implying that UE researchers should have on average more publications due to an age-effect alone.
The fact that the numbers do not show such a bias only bolster the conclusion that
these methods are likely to provide a reasonable estimate of the preeminent researchers in each group and are useful in comparing the relative expertise and prominence between CE and UE groups
Hickman asks if this may be an example of “retired man syndrome” when “scientists who have already seen the best days of their career pass them by develop a contrarian view in an attempt to seek validation and court attention?” That would certainly fit the bill for Freeman Dyson, for one, who despite not publishing anything even remotely close to the subject for decades, sees fit to challenge the experts now actively working in the field.
At the very least, it would be a good idea for a reporter preparing a story on climate change to check Prall’s database before quoting an unfamiliar climatologist.
Anderegg, W., Prall, J., Harold, J., & Schneider, S. (2010). Expert credibility in climate change Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1003187107