Climate Change: How much agreement do we have from the subject matter experts?

images (28)Read some press stories and you would get the impression that the topic of Climate Change is one that is disputed by a lot of serious scientists who have made an entire career out of studying all the evidence in detail. (Mr Dellingpole, I’m thinking of you). However, what are the numbers, what do we really know regarding the consensus or lack of it within the scientific community? Well, we have an answer because a survey has been conducted

… two dozen scientists and citizen-scientists from three continents–including Sarah Green, professor and chair of chemistry at Michigan Technological University in Houghton, Mich.— analyzed the abstracts of nearly 12,000 peer-reviewed scientific papers on climate change published between 1991 and 2011. They also surveyed the authors of those papers, to find out how well the analysis agreed with the authors’ own views on how their papers presented the cause of climate change.

Ah, now that is indeed an interesting approach. Note that they conducted an analysis of peer-reviewed scientific papers, so this was not just an opinion poll.

An important point here is that an opinion is just that – an opinion. Things are not true, no matter how beautiful it is, or how popular it is, or who said it, if there is no actual evidence then it can be rejected. In stark contrast, a peer-reviewed scientific paper has a rather higher status because it is evidence based. When submitted for publication, the whole point of the peer-review process is that the editor of respected publications (we can ignore the fringe journals published by cranks) will send it out to subject matter experts to review and verify not only that it is appropriate for the journal in question, but to also verify that the data presented supports the position that the paper is taking. Any papers presented might face rejection, or instead suggested clarifications might be asked for, but if well presented and transparently verifiable, then it generally deserves to be accepted for publication. While it is of course not a perfect process, and is after all just the start of a conversation within the wider community, you can be darn sure that what gets published has indeed gone through a lot of scrutiny prior to publication. This essentially means that an analysis of peer-reviewed papers on the topic of climate change is, by definition, an analysis of the evidence, not just an opinion poll, thus it makes the numbers of any such survey a lot more meaningful.

What did they find, what was the conclusion?

The link that reports it all sums it up nicely

They found that more than 97 percent of the scientists who expressed any opinion in their papers about the primary cause of global climate change believed that human activity was the cause. Approximately the same percentage of authors who responded to the survey said that their papers endorsed anthropogenic (human-caused) climate change.

“Oh but wait, you are just linking to a story about the survey, and not the details of the actual survey”. True indeed, the scientists who analysed the abstracts reported their findings in the journal Environmental Research Letters, (published by the Institute of Physics), so here is a link to that paper if you would like to check it out for yourself. The abstract reads …

We analyze the evolution of the scientific consensus on anthropogenic global warming (AGW) in the peer-reviewed scientific literature, examining 11 944 climate abstracts from 1991–2011 matching the topics ‘global climate change’ or ‘global warming’. We find that 66.4% of abstracts expressed no position on AGW, 32.6% endorsed AGW, 0.7% rejected AGW and 0.3% were uncertain about the cause of global warming. Among abstracts expressing a position on AGW, 97.1% endorsed the consensus position that humans are causing global warming. In a second phase of this study, we invited authors to rate their own papers. Compared to abstract ratings, a smaller percentage of self-rated papers expressed no position on AGW (35.5%). Among self-rated papers expressing a position on AGW, 97.2% endorsed the consensus. For both abstract ratings and authors’ self-ratings, the percentage of endorsements among papers expressing a position on AGW marginally increased over time. Our analysis indicates that the number of papers rejecting the consensus on AGW is a vanishingly small proportion of the published research.

Is this a surprising result?

In one word, “no”, the 97% figure exactly matches prior surveys.

Does this matter?

Apart for the obvious concern that we should have about what we are doing to our current planetary climate and the impact AGW will have … (hint: doing nothing is not an option) … we can also see that the claims of some climate change deniers regarding the lack of a scientific consensus is completely fictitious. The only recourse they have in the face of this consensus is to either lie about its very existence or alternatively perhaps suggest that science itself is broken. How that could ever work I have no idea, if not science then what? Once you abandon the well-proven scientific methodology, you really are left with no way at all of working out the things that are actually true.

Sadly we still have a huge disconnect between the public perception of the scientific consensus and the reality. This matters because it is not an obscure abstract topic, rejection of the prevailing scientific consensus will have dire consequences for the very existence of humanity.

For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled. – Richard P. Feynman

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