Bishop Hill Gavin and straw men
Apr 13, 2013 Climate: Models Warren Pearce has written an interesting layman's guide to sceptical arguments on climate change at the Making Science Public blog. He covers issues such as Climategate and science by press release in what I think is a reasonable summary.
The section on computer models was also quite good:
Computer models are critical to climate science and the projected effects of carbon dioxide emissions on global temperatures. Criticisms are levelled at these models sometimes focus on the assumptions upon which they are based. More broadly, there are worries about the weight afforded to these models over empirical observation. In other words, can we not learn more from existing temperature data than projections?
However, this elicited a comment from Gavin Schmidt that misrepresents things completely:
...the a priori demonisation of ‘models’ as a tool for making forecasts makes no logical sense – since of course we don’t have ‘empirical data’ from the future. Instead, results from coherent and physics-based models are dismissed in favor of untested and unevaluated heuristics – ‘no change!’, ‘new ice age!’, etc.
Who said anything about a priori demonisation of models? Sceptics dismiss the output of climate models as tools for policymaking because GCMs have no proven ability to make valid forecasts - to the extent that their predictions have been tested, they are running much too hot. If climate scientists want to play with GCMs, they are welcome to try. They will learn much along the way. Just don't expect us to believe the output is a valid forecast (in Gavin's words) without some evidence.
Reader Comments (37)
Where are these validated "coherent and physics-based models"? Where is the correct physics described? What fudge factors are used? If these models are coherent, why do they all give different forecasts?
Gavin fails to appreciate that we are sceptical about models because "all models are wrong". Climate models are constantly adjusted not just because they fail to forecast temperatures accurately, but because they often lack the ability to 'retrospectively predict' (hindcast) temperatures accurately. Basing real-world energy policy on models that show little skill in either forecasting or hindcasting is a recipe for disaster.
Of course we don't have empirical data from the future. But we do have empirical data from the present, which was the future in the past and this can be used to evaluate the past predictive power of GCMs. This is not "a priori".
Climate scientists have been playing with GCMs for three decades and since the range of projected temperatures has remained about the same, they apparently have not learned much in that time.
Only an idiot would try to model a chaotic system like the climate. And it takes a special kind of idiot to believe that the output from climate models is anything other than fantasy.
Surely, GCMs have a proven ability to not make valid forecasts.
Jimmy Haigh: If you pay people enough, there are plenty out there who are prepared to make a career of it.
Seconding the views expressed here and quite apart from the fact that so far as I know 10/15 years ago not a single GCM forecast the standstill in global temperatures, is it not the case that exactly these same GCMs were used to predict the path of the ash thrown up by the Icelandic volcanic eruption in May 2011 and got it dead wrong, as was shown within about a week or so, having meanwhile cost airlines millions and disrupted flights across the globes? Sound pretty empirical to me.
Warren Pearce also has this to say about the Marcott paper:
The Met Office have yet to concede their own role in miscmmunicating this result and appear to have spent the past ten days or so deciding how to present a suitable grovelling correction.
Interesting times. We are seeing who the true defenders of the faith are: Mann obviously intends to go down with the ship. Schmidt will keep telling us how great models are until he is 10 feet under an ice sheet.
Contrast Myles Allen on C4 the other night. As I said at the time not quite as cock sure as past offerings. I think we will see as the bollox unwinds a division between the hardcore true believer activists and those who might just be more interested in the science. As that develops watch out for the internecine battles.
Interesting times.
Apr 13, 2013 at 9:28 AM | Registered Commenter Phillip Bratby
A whole industry has been created out of it as we know. An absolute travesty. I was going to say: "A special kind of idiot - or politicians". But I thought I'd be repeating myself...
M'lerned friend noTrophywins says:
'Contrast Myles Allen on C4 the other night.As I said at the time not quite as cock sure as past offerings.'
If he had backpedalled any faster he'd have fallen into the Oxford Canal which formed the backdrop to his interview.
Allen has located the muster stations, nervously eyed the lifeboats and is calculating his chances of survival by staying onboard, or by jumping into the rescue boat.
But is it not hugely encouraging that - at the first sign of even a mildly tough question from the media - the alarmists start to go into full damage limitation mode?
Once they step outside their little cocoon composed of 'academic authority', sycophancy , groupthink and self-delusion they have very little to say. Seems to me that they've been protected from real debate for so long that their game is tired and flabby.
Now the MSM are starting to give them a slightly harder time than they have for years, we will see who among them can play the big matches...and who will have to stay hidden in the reserves. I don't think that they have may Rooneys or Cantonas or Beckhams who can shape up for the really big ones.
And I'd pay really good money to see Paxman vs Slingo as she propounds her 'we're all so f...g cold because of global warming' theory.
Gavin does make a valid point. If we did have ‘empirical data’ from the future I am sure that the models could be made to predict the data accurately!
Whenever I read GCM's my first thought is garbage in garbage out and go make a coffee.
Martyn, There's a special variant of "GIGO" for this: Garbage In, Gospel Out.
It fits so well with the behaviour we have seen recently whereby anything which appears to support the cause is instantly heralded from the highest peaks.
If you rely on your unvalidated model, you are worse off than if you have no model at all.
Latimer, it's worse than you think Julia is telling the world we've had a normal because of global warming.
"So just how cold have Britain’s winters become? Well, according to the Central England Temperature series, not very! The winter just gone ranks an unremarkable 187th coldest in the 354 years since the index started in 1660. Figure 1 shows just how unremarkable it has been. The 2012/13 winter finished at 3.83C, a fraction above the mean over the whole record of 3.72C."
Paul Homewood on WUWT
I believe the alarmists have had such a long stretch of having the media field to themselves they've taken to saying the first thing that comes into their head to prove global warming is dangerous safe in the knowledge that they won't be challenged by the press. We've a long way to go.
Models 101:
Models are not reality.
Models must be tested to see whether they resemble reality.
Models are tested in various ways depending on the type of model (e.g., model airplanes, electrical circuits, mathematical, analogue, digital etc.).
The production of models is not an experiment even when computers are used. The testing of models might or might not be an experiment depending on its design.
Models of the future can be tested only by the passage of time.
How embarrassing!
http://m.urbandictionary.com/#define?term=schmidt
Surely the only way out of this has to be the open source, public development of rival GCMs by serious amateurs obstinately following the scientific method, the only admitted motivations being curiosity or the ‘thirst for knowledge’. There is plenty of computing power available.
For a long time the LINUX community has been developing software which is mostly better than the commercial counterparts, but which might need some knowledge to be used profitably and, because there is no support, this free software is not always suitable for those who choose to regard themselves as totally computer illiterate.
Hands-on numerical climatology would attract as a sort of hobby activity many who have actual experience in comparable work and who have time to contribute. Typically they would already have a powerful computer at home and would possess sufficient programming skills.
It might be best to start with the basic physics and try and compute detailed conditions on the Moon, on Venus and on Mars because they would be expected to be less complex than Earth. Their idealisations would be more straightforward. However, the fundamental CO2-H2O interaction would be missing.
Furthermore, climatology is not only the basic physics. There is the basic chemistry and the basic biology as well, not forgetting the complicated interactions amongst them.
It goes without saying that the professionals would oppose such a development with every means at their disposal.
Warmists can always look down on sceptics as ignorant outsiders because sceptics have no access to the politicians, they have no funds, they do not control the observational data, they have no GCMs and they don’t know what goes into the existing simulation programs. (They never answer blog questions about modelling details.) But there are certainly very many honest sceptics who are perfectly capable of designing and implementing independent GCMs in cooperation with like minded individuals.
I would say the criticism of the models is definitely a posteriori: the polar opposite - see what I did there ;) - of a priori.
Barbara, you picked the words from my mouth. Gavin must think that using Latin expressions or words like Quantum Physics (see newest post on Anders Levermann's letter to the economist) then your argument has to be correct.
"...the a priori demonisation of ‘models’ as a tool for making forecasts makes no logical sense."
I beg to differ as by any logical review of the worth of the models used reveal that at best their short term outputs are spurious, long term they have proven themselves inaccurate. Using these models with all the underlying fudge factor as a scientific tool is nothing short of fraud.
Gavin: "physics-based models" - so what? They might be physics based, but in the same way that every year countless science students submitting exam scripts will supply incorrect answers that are "physics based".
As far as I can tell, the modelling community have not got one single success to point to and all they do is try and invent new ways of framing performance analysis to hide the fact.
Perhaps Im wide of the mark but when someone from the team makes themselves an easy object of derision why not take the opportunity to engage with them :)
Dont you love someone with a good sense of humour...and I bet you said that with a straight face :) Gav, IF all scientists were sceptics we wouldnt be in the position we are today where scientists like yourself, your chums at real climate and sceptical science etc have corrupted the field of climate sciences and in all reality have probably held back the field for decades thanks to your slavish devotion to the catastrophilia that passes for Mann Made Global Warming (tm) these days.
Yet if we went back 15 years the data we have today IS the empirical data from the future AND not only that but the empirical data has destroyed the voodoo that spews from your beloved GCM's.
Besides, isnt it interesting that so often we see supposed climate scientists answering a question that was never asked. I reckon their is a career in politics awaiting you :)
And yet Marcott et al did exactly this, they went to the media to trumpet their findings that the warming seen today is even worse than expected yet when asked searching questions (you know, the kind the peer reviewers should have asked) Marcott had to admit that his findings for the 20th century were not robust. So the question is, why did Marcott et al go to the media with their claims and, probably more importantly, how did their paper get past peer review in the first place?
Because their paper got through peer review one wonders who input the hockey "team" had in to getting through peer review? Perhaps Gavin you could clarify IF any real climate scientists were involved?
The thing is Gavin, if you were truly a sceptical scientists (like you claim) how is it you can support scientists whose findings are nothing more than the results of their data processing (Stigg et al), the use of upside down proxies (Mann) the creation of mythological warming of the deep oceans where no data supports this fantasy (Travesty Trenberth) and of course climategate 1, 2 and 3...the list is endless!
Instead of labelling anyone who dares question the religion of Mann Made Global Warming (tm) as deniers you could instead work with the likes of the anti-christ...opps, sorry I meant McIntyre, to sort out the use of your (thats a royal you btw) novel statistical methods etc. But no...thanks to the poisoning of the debate that real climate has been an all to eager contributor this will never happen.
Now if you will excuse me, I have a big fat juicy cheque from the Koch brothers to cash!
Regards
Mailman
The Met Office have yet to concede their own role in miscmmunicating this result and appear to have spent the past ten days or so deciding how to present a suitable grovelling correction.
Apr 13, 2013 at 9:39 AM matthu
Yes, the suspense of waiting is unbearable.
It is obvious why CGMs are so great: they are validated by their accuracy in forecasting the past. And Mann's reconstruction of the past is validated by their adherence to the CGMs.
Simple.
"Instead, results from coherent and physics-based models are dismissed in favor of untested and unevaluated heuristics"
I don't actually understand what he means here. Anyway, Angry Birds is physics based and from that I assume that black coloured birds like crows and male blackbirds explode when they hit things.
Now I am getting scared. Schmidt sounds deranged.
Rob Burton:
Indeed, but, whooah!, Gavin, the Super-Brain itself, can use words like 'heuristics'. Now that's what I can seriously grown up. Only the biggest brains . . .
Whoopsy. For 'can' pls. read 'call'.
since of course we don’t have ‘empirical data’ from the future
This is the very embarassing strawman and so typîcal of the agw morons.
Gavin Schmidt misrepresents things completely, yes I would say that is a fair enough claim .
"Instead, results from coherent and physics-based models are dismissed in favor of untested and unevaluated heuristics"
That same old strange fallacy: the idea that in order to criticize a theory or a model one must have a replacement theory or model in place. If this thinking were correct then criticism would be possible only between two theorists who have theories that are logically incompatible but empirically equivalent. In other words, criticism would be all but nonexistent.
Sorry, Dr. Schmidt, but criticism can be legitimate when one has discovered a fact that contradicts a theory, when one finds an inconsistency in a theory, or for many other reasons. And failing to recognize legitimate criticism and change a theory that has met with legitimate criticism can lead to enormous harm. Accept the legitimate criticisms of your models and your so-called theory of climate.
The 'a priori' was the assumption that the models would be useful for short term policy making.
The number of a prioris in the models far exceed the physics anyway
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The 'a priori' was the assumption that the models would be useful for short term policy making.
The number of a prioris in the models far exceed anything else in any case
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