The Sleepwalkers: A History of Man’s Changing Vision of the Universe is a 1959 book by Arthur Koestler, and one of the main accounts of the history of cosmology and astronomy in the Western World, beginning in ancient Mesopotamia and ending with Isaac Newton. At least, that’s what wiki sez, so it must be so. Its a good book; I recommend it. It isn’t flawless – one of its entertaining ideas, that no-one really read Copernicus’s De revolutionibus orbium coelestium – has been, shall we say, heavily challenged by Owen Gingerich (that book is quite good too, but a bit laboured). But at the worst that bit can be counted as a “fruitful mistake”.
Its really an account of the history of the Copernicus / Brahe / Kepler / Newton shift from geocentric to heliocentric astronomy, and from an essentially geometric view to a physics-based one (see-also my Feynman on Brahe for a detail, from which I find I’ve linked Science controversies past and present, also worth a read).
The entire process is endlessly fascinating, but the point that I keep coming back to wonder at is the epicycles. This starts with the Greeks, who decided something like: the heavens are perfect, circles are perfect, therefore planets move in circles. I may have simplified just a little, but not much. The Greeks weren’t heavily into observations, so my suspicion is that the people who thought this up didn’t really believe it, or much care: it explained what they needed, and that would do. People who actually needed to predict the movements of the planets then found it was inaccurate; and for such practical people adding enough epicycles left you with the ability to predict far enough in advance. And somehow the idea that perfect motion was circular was reconciled with the the full knowledge that the motion modelled was composition-of-circles, which isn’t circular, and isn’t perfect. Weird.
And somehow this because the accepted model of reality. Since at that point they had no physics the fact that it was physically ridiculous wasn’t a cogent objection. But somehow what should have been an objection, wasn’t: that you couldn’t make one epicycle model fit all the observations. So you had different, incompatible, models for different situations (I struggle to remember the details, do feel free to help me out, but I think it was position / speed / distance. You can tell, I think, that I have little patience with the details: like the antient Greeks, I’m not a detail man).
And now (like some long-winded C of E vicar) I finally come round to my point. Which is trying to talk about past temperature variation with the self-described “lukewarmers” (I know, I know: what’s the point you cry? Well, you have to try. Or at least someone has to). The bizarrely-enobled M Ridley asserts (in a piece once published by the GWPF but now taken down for unclear reasons, but copied by TF; webcite) that:
We now know there is nothing unprecedented about the level and rate of change of temperature today compared with Medieval, Roman, Holocene Optimum and other post-glacial periods…
You might wonder “how do we know this”? If you’re MR, or part of the septicosphere, the answer is easy: you know it in the same way that antient Greeks knew the planets moved in circles: its obvious; all your friends know it; and anyone you ask knows it; its part of your mythology. What more is needed? MR’s answer is Ljungqvist, which we’ll come back to in a bit, but the problem with that is that it only goes back 2kyr, so doesn’t cover the HO. TF isn’t fazed by that, however, because he refers me to the wiki page I’ve inlined. So I said:
First of all, its a pile of wiggly lines. None of them are in any sense a global or hemispheric series. You’re obviously not choosing to take the max of the envelope, because that would be cheating. So perhaps you’re taking the thick black line. Which is colder than 2004, which is colder than now.
This just bounces off TF. Eventually, after several iterations, it turns out that he really is choosing to take the max of the envelope as his temperature series. Put that way, its obviously wrong, so he says the same thing in different words in order to disguise this from himself:
Every place that produced data produces warmer temperatures than the present during the Holocene.
So that’s it: we know that the planet as a whole was warmer, because individual locations, and different times, were warmer. That the average was cooler doesn’t register: its not the answer they want to hear. Its the epicycles again: you can fit some of your observations with one set, and then you switch to another set at need. The idea isn’t even self-consistent, because you could find obs of individual locations of now that show positive – or negative, if you pleased – swings; but that too wouldn’t mean much.
But what of Ljungqvist, I hear you cry? Indeed. MR is good enough to reproduce a figure from L, or rather as he coyly says “Adapted from Ljungqvist”. Here is the adapted version:
Nice, eh? All conveniently labelled to lead the eye. And look, its colder now that it used to be. Cased closed? But wait, here’s the original:
Notice anything… different? I don’t mean the lack of glorious technicolour that MR added. No, I mean there seems to be something… missing… in MR’s version. What can it be? I’m sure if I look hard I’ll be able to see it. Oh yes! Its that dotted line at the end – the one that ends up higher than the rest of the graph. What can it possibly be? Oh yes, its CRUTEM3+HadSST2 90–30°N record, decadal mean values AD 1850–1999. How very careless of MR to have somehow omitted that line in the process of copying out the figure.
So now we know how MR proposes to support his assertions: provide evidence that doesn’t cover the period in question, and erase information that contradicts his assertions – even when that comes from the very refs he is quoting.
Although, in fact, all of this isn’t terribly relevant to anything that matters. I’m only going into it because I happened to fall into a pit of argument, how very unlike me.
Notice that very little gets said about the rate-of-change in all the above. That the current rate of change is not unprecedented is one of MR’s points, but one he doesn’t even attempt to support. Since it looks increasingly likely that the Eemian (last interglacial, keep up at the back there) was warmer than now, I at least would be inclined to go for rate of change as being more important that absolute temperature as a problem. That fits in with the problems-likely-to-come-from-ecology viewpoint, too. I’m sure I’ve said that before, or perhaps just agreed with it. I comment on it in a comment, if that helps.
[Update: TF has partly acknowledged his error; no signs of MR waking up. I say partly because "challenged that statement and I found that I could not back it up" isn't really a fair description of the discussion. A closer description would be that I pointed out, in a variety of different ways, the same problem: that he had no evidence for what he was asserting. This bounced off time after time: TF wasn't thinking. Finally, Jim Bouldin shows up and tells TF I'm right - and TF instantly caves in to authority. This is no way to convince anyone that you're open to reasoned argument.
He also fails the "hide the incline" tribality test, too.
And then updated to add the Frost quote, because it is almost appropriate and unbearably beautiful -W]
[Update: RH points out that MR is just unthinkingly copying his airbrushing from the Idsos: http://www.co2science.org/education/reports/prudentpath/prudentpath.pdf. So on the plus side, he didn't wield the airbrush. On the minus side, it means he was dumb enough to trust the Idsos -W]