So I read with some bewilderment1 a recent article by Professor S. Fred Singer on climate change. It jumps around a bit but mostly tries to attack the idea of scientific consensus. Singer’s logic leads from platitudes like this:
Scientific veracity does not depend on fashionable thinking.
to risible conclusions like this:
In other words, the very notion of a scientific consensus is unscientific.
This makes less sense than the reader comments beneath climate-related news articles. Take any established theory from any other scientific discipline — General Relativity, the Standard Model of particle physics, Evolution, Germ Theory, Genetics, etc. ad infinitum. If you follow Singer’s logic, these are all “unscientific”, not just in spite of overwhelming scientific support, but actually because of it. Presumably something can only be “scientific” if a large number of scientists disagree with it. This takes denialism to a whole new level.
The fallacy underlying Singer’s thinking (assuming, for the hell of it, that he’s actually being honest) is that “consensus” is equivalent to groupthink. Singer hasn’t apparently grasped the idea of a conclusion being arrived at independently by many people. But that’s what you should generally expect to happen if (a) we live in a universe that obeys rules, and (b) those people apply sufficient rigour in their observations and analysis, as scientists are expected to do.
But why is consensus important? Because we rely on experts all the time. An “appeal to authority” is perfectly rational when there is a disparity in expertise, as between climate scientists and laypeople. It’s not the scientists who rely on scientific consensus. They rely on rigorous observation and analysis. But laypeople lack the time and expertise to do the same, and for them (us), the notion of a scientific consensus is immensely important as a way of assigning credibility to particular scientific ideas.
Singer’s article actually begins by denying that any consensus exists at all, which is contrary to a number of surveys, and (if you pay attention to those who write about this sort of thing) the absence of any significant pool of climate expertise on the sceptic side of the debate. Singer is aware of the 97% figure — the proportion of climate scientists who agree that climate change is real and human-cased. His response? First of all:
The degree of consensus also depends on the way the questions are phrased. For example, we can get 100% consensus if the question is “Do you believe in climate change?” We can get a near-100% consensus if the question is “Do you believe that humans have some effect on the climate?” This latter question also would include also local effects, like urbanization, clearing of forests, agriculture, etc.
The word “some” (underlined by Singer) is the key to his whole argument — an issue of wording on the survey questionnaires. Here are three surveys (of actual real-world climate scientists or climate science papers) that have each independently reported a 97% consensus:
- One by Doran and Zimmerman (2009) that I discussed three years ago, which asked scientists the question: “Do you think human activity is a significant contributing factor in changing mean global temperatures?” (my underlining).
- One by Anderegg et al. (2010), which classified 1,372 climate researchers as either convinced or unconvinced of the IPCC’s position, which is of course that humans are making a significant contribution to global temperature increases.
- Another by John Cook et al. (2013), who examined and categorised 11,944 climate-related abstracts. Abstracts that minimised the impact of humans, or claimed that humans contribute less than half of the total effect, were counted as a rejection of anthropogenic global warming (AGW). This is another term for human-cased climate change, of course, but one that makes explicit its global nature.
In order words, the bar is set a lot higher, and so the consensus a lot more meaningful, than Singer makes out. Those who believe that humans are having “some” effect on the climate, but only a local or minimal one, have not been counted in the consensus.
Singer himself brings up a fourth survey by Oreskes (2004), which also found a consensus view among published papers. Singer only mentions this in order to dishonestly imply that something scandalous happened:
The “discreet” correction is advertised in large capital letters across the top of the downloadable PDF. The correction says:
The keywords used [in searching for papers] were “global climate change,” not “climate change.”
Not quite the same thing as “overlooking 11,000 abstracts”, which is Singer’s preposterous interpretation2. And notice that even the correction itself, raised by Singer just to spread doubt, again undermines his own point – we’re talking about global climate change here, not local effects.
In the midst of this, Singer has the audacity to cite his own survey without furnishing us with the wording of his questions3, finding of course that support for human-caused climate change is much lower. He does, however, tell us that it was done in 1990 with less than 100 respondents. It was also apparently targeted at the American Meteorological Society, because:
I figured those must be the experts.
Just smell the rigour. Meteorologists are not the experts — climate scientists are. But even if we assume the survey was done rigorously, it’s still much smaller than all of the above-mentioned surveys, and 24 years out of date.
But Singer also confuses surveys of climate scientists with public opinion polls:
On the other hand, independent polls by newspapers, by Pew, Gallup, and other respected organizations, using much larger samples, have mirrored the results of my earlier AMS poll. But what has been most interesting is the gradual decline over the years in public support for DAGW, as shown by these independent polls.
The public does hold a much more cynical view of human-caused climate change than climate scientists, but Singer’s comparison here is utterly absurd. “Respected organisations” these pollsters may be, but what they do has no bearing on the existence (or otherwise) of a scientific consensus. They’re surveying laypeople, whose understanding of scientific issues is more a function of media coverage and ideology than of observation and analysis. Does Singer not understand the difference?
His other notable example is the “Oregon Petition”, said to have been signed by 31,000 “scientists and engineers”, 9,000 with PhDs. It’s clear that the list of signatories to the petition includes a very broad swathe of qualifications, most of which have nothing to do with climate science, and the majority of which probably have no connection to the active pursuit of scientific research at all (since a PhD is a basic qualification for a researcher in academia, and since less than a third of signatories claimed to have PhDs). The petition’s website itself states that only 31 signatories have a “climatology” qualification, a mere 0.1% of the total. It doesn’t say these are even PhDs, so they almost certainly include non-scientists. After all, the petition failed to ask signatories what they actually do, or in fact anything about them at all other than their name and self-reported qualifications (making the list impossible to verify). Singer also doesn’t concern himself with the difference between a petition and a survey. The former gives us a big, but ultimately meaningless number. The latter, more usefully, gives us the proportion of respondents (experts, in our case) who hold a certain view.
Singer’s other argument against the existence of the consensus is that there’s a global peer-review conspiracy. He complains about the corruption of the process — as evidenced by a few anecdotal examples gleaned from the “climategate” collection of stolen emails, in which scientists and journal editors are seen to be exercising their professional judgement. The whole point of peer review, of course, is to act as a front-line filter against the least meritorious scientific papers. Of course someone, somewhere, is going to have been making recommendations and sending communications about the worth or worthlessness of certain papers. The fact that so few climate sceptics ever get past this first hurdle annoys them terribly, but it doesn’t mean that the peer-review process across the world’s entire climate science community has become mired in systemic corruption. It could simply mean that said climate sceptics are full of shit (and doubly so for then claiming persecution). Given the quality of Singer’s other arguments, it’s hard to give him the benefit of the doubt.
Singer also briefly wheels out the “no warming for 15 years” myth, and complains that the fact of it having been the warmest decade on record is irrelevant. He comes armed with this self-defeating analogy:
It may help here to think of prices on the stock market. The Dow-Jones index has more or less been level for the last several weeks, fluctuating between 15,000 and 16,000, showing essentially a zero trend; but it is at its highest level since the D-J index was started in 1896.
Singer argues that the current level does not indicate the trend, which is technically, pedantically true, but we’re never just talking about the current level. By saying that the Dow-Jones — or the current temperature — is the highest it’s ever been, we’re relating it to past levels, which is what a trend is all about. Singer just doesn’t want to admit that there’s such a thing as a long term trend that overwhelms whatever short-term trend he might find interesting. In the course of arguing that the Dow-Jones hasn’t changed much in weeks, Singer is actually conceding that it has changed considerably over the longer term. So, of course, has the global temperature. And it’s the long term trend that matters.
That’s certainly the case for climate models, which Singer laughs off for their apparent inability to explain short-term natural variability. But short-term variability is basically irrelevant in determining the broad magnitude and impact of climate change. A model doesn’t get “falsified” for failing to produce a level of precision that it doesn’t need and was never designed to produce. Run the models against the past temperature record and they quite successfully predict the large-scale shape and magnitude of the rise that we’ve observed.
Singer ends with a plug for one of his own creations:
The wild claims of the IPCC are being offset by the more sober, fact-based publications of the NIPCC (Non-governmental International Panel on Climate Change).
This is sheer delusion from the man who set up the NIPCC, which appears to be a group of cranks angry at not being taken seriously. The IPCC already considers and incorporates into its reports the full range of scientific opinion on climate change. Far from being “wild”, its claims are often considered quite conservative. Singer’s claims are nothing but denialism.
- In the naïve sense of one who expects intellectual honesty. [↩]
- Presumably someone did a search for “climate change” and noticed that the tally of results was 11,000 higher than that reported by Oreskes. You might think that the simple, accidental omission of one of the search terms would explain the disparity in results. But the climate sceptics, bastions of reason that they are, know that really Oreskes must have had all those extra papers at hand and dishonestly or incompetently misplaced them. Because that sounds better. [↩]
- For instance, did Singer ask survey respondents whether they believe that humans will cause the world to end, and did he count each “no” response as a rejection of human-caused climate change? He doesn’t see fit to tell us, even after raising the issue of wording. [↩]