Tuesday, March 12, 2013

Climate science is pseudoscience(?)

So says Ivo Vegter in his latest column, calling up the spirit of Karl Popper.

I drop by in several places in the comments, saying that this pretty much utter nonsense according to any reasonable definition of the falsifiability criteria. For example:
[...]As it happens, Ivo has also beautifully misconstrued the application of Popper's insights, by consistently conflating the actual science with the response to that science by various parties.
[...]At its heart, falsification is about using an underlying set of theories to make predictions that can be tested against the relevant evidence. The theory of (man-made) climate change satisfies the falsifiability criteria across multiple dimensions. The fundamental pretexts of climate science are rooted in physics that has been understood and tested since the early contributions of Fourier, Tyndall and Arrenhuis in the nineteenth century. For their part, modern day climate models absolutely meet the Popperian standards. Not only do they forecast how climate phenomena will evolve under conditions of continued emissions, but (crucially) they have been extremely successful in hindcasting previous changes to the climate. Indeed, this accurate replication of past events is how they are selected in the first place…
As part of his reply to this comment, Ivo made the strange assertion that the ability to hindcast models is weakened by the fact that these models can be "tweaked" to accurately match the observed data. I respond:
How is it a case against climate scientists that they were able to benchmark their theories against against a historic record with "perfect hindsight"? Speaking as someone with a fairly considerable amount of scientific training, that actually sounds pretty ideal. Models were back-tested, refined and then discarded in favour of ones that better fit the data... pretty much in exact accordance with the scientific method.
For the record, I am well aware that Popper's falsification doctrine is not without its problems. Still, and at the very least, if someone is going to invoke his authority to make specific claims, then they should at least make sure they are accurate within that framework.

UPDATE: Oh God, it gets worse. Someone responds to me with the immortal line: "I have not done the research but from my own basic calculations..." *headvice*

UPDATE 2: See this excellent 2005 post by NASA's Gavin Schmidt: Is Climate Modelling Science? It concludes: "So, in summary, the model results are compared to data, and if there is a mismatch, both the data and the models are re-examined. Sometimes the models can be improved, sometimes the data was mis-interpreted. Every time this happens and we get improved matches between them, we have a little more confidence in their projections for the future, and we go out and look for better tests. That is in fact pretty close to the textbook definition of science."


  1. Grant,

    Your responses to Ivo are like gold for me... the best I can manage is some give and take on Twitter :)

    Rich Palmer

    1. Thanks Rich. Slogging it out in internet debates is normally a pretty thankless task, so I'm glad that someone is appreciative :)

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  3. Interesting post and this is an important issue in my opinion. I think that those who are trying to use philosophical arguments to show that climate science is wrong or flawed don't really understand how science works.

    Recently there have been a couple of articles in the Guardian which have seemed to suggest that those labelled sceptics (deniers/contrarians by some) should be given more credence and that climate scientists should be more careful about how they behave. It's my view that these views are misguided. It seems to me that it's time that climate scientists (or some climate scientists) showed some backbone and made the case that policy makers and the public should stop giving credence to the views of those who think that because they're read a philosophy book at some point in the past, that they somehow understand climate modelling better than those who actually do climate modelling professionally.

    I'm not suggesting that such people should be ignored completely. Discussions of policy are very different to discussions about the science. I'm referring specifically to how much credence we should give such people when evaluating the scientific evidence, not when evaluating what we should do, given than evidence.

    1. Thanks for the thoughtful comment.

      Yes, I think that those climate "sceptics" who try to invoke the big philosophy of science names to bolster their position, are doing so very disingenuously. Quite often, I feel that they exhibit a clear misunderstanding of these core philosophical ideas as well. (In a related note, many sceptics are certainly guilty of running afoul of the Galileo gambit!)

      As I alluded to in my post, it is widely accepted that the (naive?) Popperian falsification doctrine: (a) Suffers from significant problems in application (e.g. see the Duhem-Quine thesis), and (b) Does not really describe how science has been conducted through the ages anyway (a la Thomas Kuhn). That said, I think that Popper's arguments continue to hold useful insights for us as a guiding principle for scientific testing and benchmarking.

      This whole debate reminds me of two additional points. First, I actually happened to write this blog post while taking a "Philosophy of Science" course as part of my mandatory PhD coursework. I showed my prof the article that I am criticizing above and he just laughed, saying something along the lines of, "These people show very little understanding of Popper and scientific practice." The second point is that I actually wrote my term-paper for this particular course on policy advocacy among climate researchers. Perhaps I should make it available here...

      PS - Other readers may be interested to see WoUWT's related post here, which is what prompted my directing him to this older post.


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