Friday, August 6, 2010

Climate Science Credibility

It “used to be” a maxim that if your case was without merit, all you could do is blame the messenger. Used by politicians and others in the legal system, I have experienced this a couple of times. Along this line the United States National Academy of Sciences has published in its proceedings a paper-- "Expert credibility in climate change," available in their open access option, reserved for a set of papers they think important enough to have wide circulation. Otherwise non-subscribers are limited to abstracts and a few other features.

The authors divide climate scientists into two groups, unconvinced (UC) and convinced of the evidence (CE), but start the paper with the statement that “....surveys of climate scientists indicate striking agreement with the primary conclusions of the Intergovernmental Panel on Climate Change (IPCC)...”, which are that it is real and we have largely done it, making carbon dioxide a demon that we need to and can control. The authors make the logical error of concluding what they set out to prove (confirming the antecedent). In the same paragraph they state “A vocal minority of researchers and other critics contest the conclusions of the mainstream (emphasis mine) scientific assessment...” This is a contradiction because their data shows roughly similar numbers in both categories, so by definition the UC group is in the mainstream, at least of their sample. The reasoning is circular. How could an editor miss this?

They produce two arguments. First, credibility is established by the number of papers published in the field and second, the number of citations of those papers. This is an appeal to the authority of popularity (Argumentum ad Populum), which by itself is a poor judge of quality. The paper presents no merits about Anthropogenic Climate Change (ACC), formerly called AGW (Global Warming) before the data was called into question, and arguing there is good reason, with some caveats, that their hypothesis (lack of credibility based on poor numbers) has a basis. They present no alternative hypotheses, but clearly others are worth discussing. Most striking is their Figure 2 showing numbers of papers of the top 50 researchers (again by numbers) in each group. With a small exception all of the UC produced less than the CE, almost completely separated, with the split near 250. The groups are so segregated that the data seem too well ordered to be true.

Noteworthy, they found that the first group of climate scientists is a decade older, not factoring in changes in publication practices such as a possible increase in multiple authorship.

A very recent paper found that a quarter of citations sampled from research papers in marine biology journals had some degree of error. Twenty five percent error in a physical system would fail after a few iterations, but this would be more complicated. Nevertheless the paper’s authors thought this “alarming.” They cite similar studies in other, all medical, professions, ranging from very good in nursing to significantly less than either marine biology or the similarly rated ecology, to the worst--in emergency care. As a marine biologist poor citation attention is consistent with my experience, a point discussed with colleagues and librarians. Apparently no data exists for climate science.

Both the National Academy and the Royal Society of London are advocates for action, joining the many past groups of now discredited authoritarians. Even if they are correct, not likely, they have lost their credibility by producing a blacklist, perhaps towards censorship, by attacking credibility, not on the merits, but on numbers. Significant discoveries in science have largely been announced by few or even single papers, some which took a long time to develop.

Some have taken this in the context of a joke, like “where do I sign up to be a denier.” Sophomoric as this blacklist seems, it may be more serious.

More follows, but no doubt comments on this essay will be on the merits.

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