My opinion on the Global Climate Model clique feedback loop was requested by not one but two people, and how could I resist?

The text starts well, by assuring readers of the most important point, which is you don’t know enough to intelligently comment on the code itself which is true, certainly for readers of WUWT, and quite likely for many of my readers too. But already at that point its gone wrong by assuring readers this is because they need to know about computational fluid dynamics and some other stuff. This is about the most common mistake people make about GCMs. Of course they do have a fluid dynamics equation core, but that bit you can almost lay to one side, unless it happens to be the bit that really interest you, because its a fairly well known problem. Some GCMs, after all, come from or are linked to Numerical Weather Prediction (NWP) models, and if they got the basic fluid dynamics wrong, the forecasts would be wrong, and they aren’t, provably (interestingly, Easterbrook and Johns say that the codebase-sharing between the UKMO’s NWP model and the Hadley Centre’s GCM is probably unique). But there are vast piles of other stuff, that doesn’t appear directly as CFD, and it this stuff – the parameterisations, like convective cloud, evapotranspiration, etc. etc. – that’ actually more interesting, because less certain.

The post then disappears down the usual septic rabbits holes about how no-one will give them grants, which is dull. The author then decides to demonstrate that he is clueless about the models and their discretisations by saying the programs literally cannot be made to run at a finer resolution without basically rewriting the whole thing, and any such rewrite would only make the problem at the poles worse — quadrature on a spherical surface using a rectilinear lat/long grid is long known to be enormously difficult and to give rise to artifacts and nearly uncontrollable error estimates. There’s lots wrong with this – for one, the spectral models (i.e., those that do their dynamics in spectral rather than grid space) don’t suffer from this problem. For another, Fourier filtering at the poles keeps HadAM3 quite happy, and if you increase the spatial resolution you have to increase the temporal resolution. You don’t need to re-write the model, which is just as well, as it wouldn’t help. I’m assuming this is about the atmospheric models; I’m given to understand that modern forward-looking ocean models tend to use a modified grid which in the northern hemisphere maps the pole onto Greenland, thereby avoiding the problem. The author seems terribly interested in dynamically adaptive grids(he gets more and more obsessed with this the further you descend into the comments), which GCMs don’t use because they are too much trouble and too expensive and wouldn’t help, but never mind.

I don’t think the bit about treating the models as independent is very interesting. I’m more interested in whether some of them are a bit rubbish, which is indeed true; the IPCC as it seems to me decided to treat all as equal because doing otherwise would have been too embarrassing for those dissed.

Looking at the comments: Roy Spencer is wrong and he’s wrong because he is lonely because he has no-one to talk to. Nick Stokes mostly makes sense, as ever. I stopped when someone linked to http://www.cs.toronto.edu/~sme/papers/2008/Easterbrook-Johns-2008.pdf because that was more interesting.

What is wrong with models?

Ha, well, anything I can say is seven years out of date, so treat any of this with caution.

My own feeling (having ended up working with sea ice models) was that it was possible to make an atmospheric model that was sane, and an oceanic one, and a sea ice one; but putting them all together and keeping the coupled composite sane was much harder (I’m not claiming any credit for having done this – I was living off the efforts of others). HadCM3 achieved this, at some level, and as I was leaving I think they were finally beating the (much more computationally expensive) HadGEM into something almost as good :-)

The other main thing “wrong” with models isn’t a thing wrong with models at all, but in the way they are used. The GCMs are most useful for exploring and understanding the climate, and its response to changes in, say, GHGs. But as a means for detailed predictions of the future, I’m less convinced. Part of the “problem” is the way GCMs naturally end up producing maps of change at whatever their native resolution is. But that doesn’t mean you can believe it at that level of detail, however pretty it might look.

Comments

  1. #1 CIP
    2014/05/11

    I have noticed in my conversations with the skeptical crowd that they really don’t understand which parts of the models are really iffy (aerosols, cloud feedbacks) but think instead that CO2, insolation, computational problems, and direct water feedback are highly uncertain.

  2. #2 Russell
    2014/05/12

    Just as some modelers invoke the precautionary principle as an arbiter of policy taste, , the denialati can prefer worst-case assumptions when it suits them, as in summing sources of parameter uncertainty when they ought to be modeling the problem .

  3. #4 Eli Rabett
    http://rabett.blogspot.com
    2014/05/12

    Ah, a light dawns, that Robert Brown. He ran the Beowulf discussion group a pile of years ago.

    As to grants, no one is giving anyone grants these days

  4. #5 And Then There's Physics
    2014/05/12

    The other main thing “wrong” with models isn’t a thing wrong with models at all, but in the way they are used. The GCMs are most useful for exploring and understanding the climate, and its response to changes in, say, GHGs. But as a means for detailed predictions of the future, I’m less convinced.

    This does seem to be an issue. I seem to spend a fair amount of time – unsuccessfully – pointing out to people that GCMs are technically projections not predictions. They’re giving us some indication of what might happen under various different scenarios.

    [Yes. Cycling in this morning I thought "oh yeah, I should really have said that the IPCC does always insist they aren't predictions". But... there's a second half to that, which is the showing-excess-detail bit, which is just like not showing ezxcess decimal points like you were taught in O level physics; and they're doing that -W]

  5. #6 Don Brooks
    2014/05/12

    Don’t get me started on maps of climate model output…

    Another problem is that those maps invariably use nice, clean map backgrounds of the real world, with all the little islands and coastal features that simply don’t exist at the model’s resolution. Instead, output should be displayed against a map background based on the model’s own land-sea mask.

  6. #7 Paul Kelly
    2014/05/12

    “GCMs are technically projections not predictions. They’re giving us some indication of what might happen under various different scenarios.”

    Not just technically, but in fact. It is why GCMs are much more useful for climate scientists than for everyone else.

  7. #8 And Then There's Physics
    2014/05/12

    Paul,
    “Not just technically, but in fact. It is why GCMs are much more useful for climate scientists than for everyone else.”

    In what sense? I agree that climate modelling should play an important role in understanding how our climate might evolve. I can certainly see how they’re scientifically useful. Are you suggesting, however, that they have no real policy relevance, for example.

  8. #9 Hank Roberts
    hankroberts.wordpress.com
    2014/05/12

    > some indication of what might happen

    each run gives us one indication — and these are run multiple times, under each climate scenario, to get some idea of the range of possible futures that particular scenario may lead to.

    That’s where they’re useful for policy. “What could happen?”

  9. #10 Steve Bloom
    2014/05/13

    OT: If this doesn’t result in a “Timmie is a tosser” post, clearly there’s nothing that could.

    [Meh. I read the headline and couldn't face reading the inevitable stupidity that was the fate of the post. Timmy doesn't understand the science, and doesn't understand that he doesn't understand it -W]

  10. #11 Eli Rabett
    http://rabett.blogspot.com
    2014/05/13

    So allow Eli to do the libertoonian waltz on this nonsense. American companies are hiding their profits overseas. In doing so they are hiding the profits from their owners, the stockholders, who deserve the benefit of those monies.

    Thieves.

    [Nonsense. Nothing is hidden; all the money is accounted for, in the company accounts. The people who control the companies are the stockholders, who approve of these actions -W]

  11. #12 And Then There's Physics
    2014/05/14

    Giving that I’ve only ever read two of Timmy’s articles, the other being this, there appears to be little he understands. Of course, I may be suffering from selection bias.

    [You don't want to read Timmy on climate science; and he doesn't understand the difference between "science" and "economics" in climate. But yes he knows a lot about economics itself. And he is correct about the relative virtues of carbon taxes and industry subsidies -W]

  12. #13 Dunc
    2014/05/14

    But yes he knows a lot about economics itself.

    Given your own level of knowledge on the subject, how can you tell?

    The people who control the companies are the stockholders

    Given the importance of institutional investors, and particularly passive investment funds, I’m not sure how true this is in practice. A significant quantity (quite possibly the majority, but figures are not sufficiently easily found for me to say right now) of stocks are not held because an active stock holder (by which I mean an individual who actually shows up and votes at shareholder meetings) has taken a decision to hold them, nor even because an investment fund manager (who basically never take any active role in shareholder meetings anyway) has looked at the stock as an investment and decided that it’s worth holding. They’re held because a tracking algorithm dictates that such-and-such a quantity of the stock must be held in order to track the target index.

    In practice, companies are controlled by their boards. They’re supposed to represent the interests of the stockholders, but the extent to which they actually do this has come increasingly into question over the last couple of decades.

  13. #14 Eli Rabett
    http://rabett.blogspot.com
    2014/05/14

    [Nonsense. Nothing is hidden; all the money is accounted for, in the company accounts. The people who control the companies are the stockholders, who approve of these actions -W]

    Don’t you think the stockholders would rather have the money in their hot little hands?

    [Quite possibly not. Many people ahve more money than they know what to do with. Besides which, the money represents value of the shares they hold. If they want to realise that money, they can sell the shares -W]

    Besides which if you think that stockholders determine the policy of large multinationals today, Eli has a name for that, denial.

  14. #15 Eli Rabett
    http://rabett.blogspot.com
    2014/05/15

    For some strange reason Eli is becoming fond of T. Boone Pickens.

  15. #17 David B. Benson
    2014/05/16

    Yawn.

  16. #18 Brian G Valentine
    Washington, DC
    2014/05/16

    Unfortunately there is no way to order “influences” in climate models except by “intuition.” The “intuition” of someone with a desired outcome has, in may cases, proved somewhat less than reliable.

    Eli Rabett falls victim to leftist conspiracy theories! Corporations aren’t “hiding” their wealth in Swiss bank accounts, Eli – they are paying off “climate deniers” such as yours truly.

    I thought everybody knew that

  17. #19 ligne
    2014/05/16

    if it really is that easy, it makes you wonder why an enterprising retired accountant or retired mining executive or retired financier or retired politician or retired weather presenter hasn’t managed to intuit an order that shows *their* desired outcome of no/minimal warming regardless of GHG emissions.

  18. #20 Brian G Valentine
    Washington, DC
    2014/05/16

    “For some strange reason Eli is becoming fond of T. Boone Pickens”

    Congratulations to T-bone for substantial investment in machinery that probably demolished more accipiters than all the DDT ever synthesized!

    For as long as I have known (of) Eli, I have noticed that his choice of “heroes” have ranged from vapid to juvenile to vindictive, with very little in between.

    This is not to be taken to be criticism of Eli at all.

  19. #21 Brian G Valentine
    Washington, DC
    2014/05/17

    “Eli has a name for that, denial. ”

    Denial! The only vocabulary the f-ing left knows!

    Don’t agree with ever idiotic thing they espouse? It’s Denial! Denial denial denial DENIAL!!!!

    JESUS HOW DID WE EVER GET HERE

    Eli, what distinguishes you from a Nazi? List the characteristics right here for us:

    [Well done. You're now on moderation. I suggest that if you want to fling around insults you return to WUWT, where they will welcome you -W]

  20. #22 Brian G Valentine
    2014/05/17

    ” … hasn’t managed to intuit an order that shows *their* desired outcome of no/minimal warming regardless of GHG emissions.”

    It is ever so easy, Linguine. Simply reverse the sign of “climate sensitivity to doubling CO2″ and there you go.

    [If its so easy, why haven't they done it? The answer is that a negative CS is unphysical; see for example here -W]

  21. #23 Kevin O'Neill
    2014/05/17

    WC#14: “Nonsense. Nothing is hidden; all the money is accounted for, in the company accounts. The people who control the companies are the stockholders, who approve of these actions -W”

    Please explain that to all the former Enron employees. They seem to have a slightly bent opinion on the matter.

    [*All* of them? You'll need to provide me with their email addresses first. But you're confused: Enron was a fraud; Apple isn't -W]

  22. #24 Brian G Valentine
    2014/05/17

    “Please explain that to all the former Enron employees”

    Enron Employees: Regrettably, Enron management placed their faith in Dumbocrat promises of “cap and trade,” and this drowned their ability to further their scheming, thus, you lost.

  23. #25 Kevin O'Neill
    2014/05/17

    BGV – obviously you have never studied the Enron collapse. Does ‘special purpose vehicle’ mean anything to you? Enron’s executives fraudulently manipulated the company’s earnings, shifting energy-trading profits in California and other states to hide more than $1 billion in losses.

    Note – the *profits* were from energy trading – NOT the losses. So your whole cap’n’trade wrecked Enron rationale is quite silly. No, it was their investment vehicles – video-on-demand, REITs,, and derivative contracts that accounted for the worst of the losses. The fact they hid these losses while pumping up the stock is what made them criminals.

    All of this done without shareholder knowledge – though the financial books had the stamp of approval from Arthur Andersen.

  24. #26 Brian G Valentine
    2014/05/17

    Kev, I hate to be the first one to tell you, that Dumbocrat promises and Dumbocrat deals were the reason Enron was Enron.

    Lies, deception, and Global Warming made Enron a perfect vehicle for Dumbocrat attempted control over energy.

    Why don’t you have the same contempt for Barbara Boxer and Harry Reid that you do for Enron? The latter were the reason Enron did what they did

  25. #27 Kevin O'Neill
    2014/05/17

    BGV – In other words, you’re clueless, but don’t care to admit it. It’s always difficult when your ideology blinds you to actual facts. Enron profited from energy trading (often by manipulative practices), but lost their ass when they strayed into other ventures.

    But let me guess, you probably believe the real estate bubble was caused by the GSEs and the Community Reinvestment Act.

    None of this changes the fact that shareholders *don’t* know where the company’s money actually is – even when the financial books have the stamp of approval from top tier auditors.

    [I think you're both wrong. Enron was simply a fraud, at the end (not all the people were fraudulent, of course. My brother in law worked for them, and he's honest) and perhaps earlier. However, all this is rather off topic -W]

  26. #28 Brian G Valentine
    Washington, DC
    2014/05/17

    You’re right, William. I have witnessed hostility toward “AGW denial” become institutionalized over the past few years, and I become too aggressive and hostile in response.

    I have learned a lot from Eli, he is a very smart individual, he is objective and realistic in all things, although his stance on AGW has left me mystified.

    I personally don’t attach too much significance to the “climate sensitivity” because the definition does not appear consistent; measurements of it from geophysical data have shown the quantity to be small, and within the error bounds of the measurements, I do not see inconsistency with the quantity assuming negative values.

    [I'm surprised to see you write that; LB's lower limit of 2 oC comes largely from observations, for example. Negative values imply an unstable climate, and are hence unphysical -W]

    People need fossil energy to survive and the implied restrictions from response to AGW take their worst toll on the least able to respond to the restrictions (or even speak out against them), I become infuriated and probably irrational. Sorry.

  27. #29 Brian G Valentine
    2014/05/17

    Strange sounding but true, I believe that “negative climate sensitivity” is a necessary (but not sufficient) condition for “climate stability.”

    Reasoning as follows: The Earth exchanges radiant heat in a clear sky with the upper atmosphere at an average temperature of about -70 deg.C depending on humidity. Increasing CO2 in the atmosphere would reduce this value (a cooling stratosphere), at the same time supposedly warming the Earth, which necessarily increases the heat transfer rate between upper and lower atmosphere. The reverse is inconsistent with thermodynamic stability.

    I won’t argue or belabor this here, you and anyone are welcome to write to me, bgvalentine AT Verizon DOT net.

    [I'm not sure you know what CS is. Negative CS would mean that if the incoming solar radiation increased, the Earth would get colder. Does that sound physically likely to you? -W]

  28. #30 Leonard O'Reilly
    Edmonton
    2014/05/18

    Whatever the merits of your writhings ( my word ) about climate models, your gratuitous comment about Spencer being lonely is unbelievably f–king childish. As a non-scientist seeking to understand these matters, how is possible to take you people seriously?

    [Ah, I'd forgotten to link "lonely" to the post where I discuss Spencer's problem. Its http://scienceblogs.com/stoat/2011/03/05/dr-roy-spencer-is-sad-and-lone/. I hope that's clearer now. You say you're a non-scientist seeking to understand these matters, and clearly you don't understand them: don't you think it would be better to ask politely for clarification of things you don't understand, rather than swearing at people? -W]

  29. #31 Paul Kelly
    2014/05/18

    And Then There’s Physics,

    For scientists in pursuit of knowledge models have almost unlimited utility. Even errors and observational discrepancies are useful as they help to prioritize future research.

    For every one else the models’ utility is limited to projections of risk. The models’ relevance to policy is thereby limited, too. The models may tell us where we’d like to be in the future, but have very little to say about how we get there.

  30. #32 Leonard O'Reilly
    2014/05/18

    I had no interest in being part of the discussion of climate models on your site since I have nothing to add to it. ( Though there was nothing in my initial comment to lead you to conclude that was “clearly” the case. ) I went there looking for a better understanding of the merits of climate models because I have heard so many criticisms of them.
    I learned two things: the first is that you are not convinced, or are less convinced, whatever being “less convinced” precisely means, of the predictive power of models. Of course, the quick qualification will be that models are meant to be projective and not predictive, though it seems to me that they are predictive when they fit the observations and projective when they don’t. ( I can anticipate your scornful dismissal that I am confused about the distinction between prediction and projection, but I would remind you that you, by your own admission, were confused about them yourself not so very long ago. )
    The second thing I learned, or more precisely, re-learned, is that it is peculiar to these climate blogs that there is no discussion so technical or so serious that it cannot descend to the snide, the snarky and the ad hominem…. to the childish, in other words. That much I stand by. By dropping the truncated f-bomb, of course, I became part of the problem, and that I truly regret.
    As I said at the beginning, I have no interest in seeing my words in your comments section. It’s enough for me to know that YOU have read them, and know that I believe you are as interested in generating provocative heat as illuminating light. To the detriment of a debate “about which there is no debate”. However much pleasure it gives you to skewer your opponents, you should know that puerile ragging is not science. It might even be interpreted as an attempt of camouflage the tenuous nature of the science.

  31. #33 guthrie
    2014/05/18

    Certainly Leonard, you have learnt English words well. Unfortunately the science regarding climate is hardly tenuous, even if you cannot recognise it. I encourate you to read more about it, perhaps Spencer Wearts book would do for starters, available free online.

  32. #34 Dunc
    2014/05/18

    Strange sounding but true, I believe that “negative climate sensitivity” is a necessary (but not sufficient) condition for “climate stability.”

    I thought I’d seen it all, but that’s genuinely a new one on me. And very, very funny… Thanks for the laugh.

  33. #35 And Then There's Physics
    2014/05/18

    Paul Kelly,
    Yes, I think I agree in general but my view on the policy relevance differs, I think. It’s certainly true that climate models can’t really tell us how we can get to a certain outcome. However, it does seem that they can provide information about the possible risks associated with various policy options. So, they may not tell us how to get somewhere, but they do say something about what might happen if we choose to follow a particular pathway.

  34. #36 Kevin O'Neill
    2014/05/18

    BGV says: “Strange sounding but true, I believe that “negative climate sensitivity” is a necessary….”

    Well, at least he recognizes that he’s probably insane. You do have to give him credit for that.

  35. #37 Paul Kelly
    2014/05/18

    And Then There’s Physics,

    I fully agree with your description of the relevance of models to policy.

  36. #38 crandles
    2014/05/26

    #16 Phil Hays “Why did Timmy ignore the time factor of the collapse?”

    This would appear to be rapid dynamics and table 13.5 of AR5 gives SLR contributions by 2100 by different scenario as:
    [quote]
    SRES A1B RCP2.6 RCP4.5 RCP6.0 RCP8.5
    Antarctic ice-sheet
    rapid dynamics
    0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16] 0.07 [–0.01 to 0.16]

    Only the collapse of the marine-based sectors of the Antarctic ice sheet, if initiated, could cause GMSL to rise substantially above the likely range during the 21st century. This potential additional contribution cannot be precisely quantified but there is medium confidence that it would not exceed several tenths of a meter of sea level rise.
    [/quote]

    The .07 obviously changes to much more – up to several tenths of a meter as indicated by AR5 quotes above. But the table is indicating that the scenario we select makes no difference.

    I suspect we can make a tiny difference to the timing but I don’t see a lot of difference between no chance of changing timing and making a tiny difference.

    If Timmy was relying on this then ideally it should have been stated to prevent that fairly obvious criticism so I might suspect he hadn’t looked up the science (and it is quite likely I haven’t done so sufficiently either).

    Do you think “Your house will burn down either tomorrow or next week,” is different from ‘Your house will slide into ocean but depending upon what you do this will either be in 20 years or in 20 years and one week’?

    I would say tomorrow or next week makes a big difference but 20 years or 20 years and 1 week makes little difference. If my efforts could make 3 weeks difference but no more then I am going to spend less on repairing and maintaining it rather than frantically working on the problem for the sake of an extra 1 to 3 weeks. Surely you have to agree that the 20 year problem is much more like the problem we face than the tomorrow/next week problem?

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