von S’s testimony

Via Prometheus I find von S’s testimony on the Hockey Stick and related issues. Interesting point number 1 is that von S has clearly noticed he is being used (or selectively quoted) by the septics, and so starts his testimony with Based on the scientific evidence, I am convinced that we are facing anthropogenic climate change brought about by the emission of greenhouse gases into the atmosphere. Maybe that will be enough to stop too many septics pointing to it.

We also have I conclude that the claim of “detection of anthropogenic climate change” is valid independently of which historical temperature reconstruction one chooses to believe in. and It should also been taken notice that the claims of successful detection on non-natural warming trends and its attribution to chiefly elevated greenhouse gas concentrations in the atmosphere in the Third Assessment report were not based on the historical reconstructions but on the analysis of the instrumental temperature record as well as on numerical experiments with climate models. Which is what RC has been saying for a while but no-one listens 😦

But its not all good news for MBH…

So whats wrong with MBH? von S says The Wegman-report claims that a major problem in studies such as MBH would be an insufficient engagement by mainstream statisticians. I think a major problem with this study and its transformation into a policy-relevant issue is an insufficient comprehension of the social dynamics of the post-normal process of (not only) climate science. Um. Whenever I hear “post normal” I think “Sokal”; I’m not entirely sure what von S means by this but if its his leading criticism on MBH, then they can be very happy, because thats effectively a criticism of the whole process, and how the study was used, not of them.

So what else? If you’re interested, read the report, I can only pick out a few bits:Nevertheless, attempts like those by MBH are useful and should be explored. They may provide useful estimates. The problem with MBH was that the result was presented by the IPCC and others in a manner so that one could believe a realistic description of historical temperature variations had successfully been achieved. The NRC report published in June 2006 has made
clear that such a belief was incorrect.
Whoompf. More a crit of the TAR than MBH, though.

the danger is that a few scholars may become powerful gatekeepers, for example as reviewers who are regularly called upon or as editors of scientific journals. The primary goal of such gatekeepers is to fend off publications which may contradict their own thinking… Unfortunately this seems to have happened in the field of historical global climate reconstructions, where a small group of scientists has exerted an undue control of the entire field. No names, but a harsh criticism of somebody.

a further mechanism more closely tied to the substance of research is used to quality control scientific knowledge claims, namely reproducibility. This mechanism has ceased to operate in some quarters of paleo-climate science, since some scientists consider “their” data as their personal property and not that of the scientific community, so that others are unable to challenge conclusions drawn from these data by analysing the raw data in their own manner… Data must be become public; the methods employed must be described in algorithmic detail. I agree that the data should become public (after a suitable period for the initial investigator to get a return on investment) without taking a position on whether this is a problem. Mind you, I know the BAS ice core folk tend not to like giving out their data even to other BAS people…

He also, fairly, ticks of Nature and Science for including “newsworthiness” amongst theircriteria for publication.

And lastly… what about being able to replicate work? Von S says:

[Scientists] should document what they have done, so that others can replicate. However, this documentation often can not take the form of keeping runnable old codes of the applied algorithms, simply because the software is no longer consistent with quickly replaced hardware. For instance, most of the state-of-the-art coupled AOGCMs used in the mid 1990s are simply no longer available and running at, for instance, the German Climate Computer Center. After replacing a high performance computer with a new system, the standard model codes, including community models, need to be adapted to the requirements and possibilities of the new system, and the old code will often no longer run. This has nothing to do with the norms of the community but simply with technological progress. Also specific commercial libraries of specialized algorithms may no longer be accessible. Data and codes written on old magnetic tapes or even floppies are usually no longer readable. Therefore the documentation must take the form of a mathematical description of the algorithms used. This is in many if not most cases sufficient for replication. Also, the intention of replicability is not to exactly redo somebody’s simulation and analysis, but to find the same result with a similar code and different but statistical equivalent samples.

The argument about no-longer runnable doesn’t really apply to the MBH stuff, as it ws std fortran. But the CM question is interesting. von S is saying the obvious: many old GCMs are unrunnable now. But to say that you *should* keep the mathematical description seems to me very highly idealised. I get the strong impression that much of the basics of models in (in theory) written down, and much of the initial versions too (HadCM3 was pretty good at that) but that as the model developes the documentation often gets left behind. You might well be able to recreate 95% of the scientific content of a model from its doc, but thats not nearly enough! And, of course, getting independent people to do this would be a huge task. And also a soul-destroying one, since its so totally pointless.

Did you notice I stopped warning you about boring HS posts? Based on the comments, its fairly clear that people don’t find it boring at all 🙂

11 thoughts on “von S’s testimony”

  1. OK, I have a minute to listen to some more. WIlliam feel free to delete if you wish (or fix the spelling – I am typoing as I go).

    Wegman is being asked questions. Currently he is saying “umm”, and “but” a lot. He was asked the question:

    You have criticized Mann for not seeking review from staticians, did you seek review from a paleoclimatologist.

    Opps, Wegman just said he did not read the IPCC.

    He is now getting grilled on the old figure from the initial IPCC report.

    Dr. Wegman just said “I was guessing” and he was asked “should statiscians guess?”


  2. Senator from Illinos up now:

    Interesting – Wegman just interrupted to agree that most climate scientists agree that the current warming is anthropogenic and that we should listed to climate scientists anout the climate. He seems to be trying to backpeddle a bit now and is claiming that he can say about AGW.

    Wegman just said CO2 is heavier than air and seems to think that it sits closer to the earth. He added that he is not an atmospheric scientist – no kidding.

    Wegman said that he hopes policy makers are smarter than to change their minds as a result of his work.

    He now is saying that the unfortunate thing is that Mann does not admit his errors.

    Wegman just said that he does not have an opinion on anything other than the PCA.

    WOW – a telling statement. He just said that the rise since 1850 is about 2F and he challenged anyone to go outside and tell a 2 F difference.

    Senator from Flordia (sp) now claiming that the hockeystick goes everywhere so shouldn’t the corrections go everywhere. Wegman just said that the diagram he is talking about is not Mann’s.

    He is now mis-quoting Hansen. Saying he agrees with Lindzen about 1/2 degree warming if we do nothing. Wegman said he did not know but tended to concure that it was not a problem.

    Wegman seems to be fixated on the ocean / atmosphere coupling.

    Wegman was just asked “is there a consensus that global warming is real and bad”. He says it is real but claims that it is not as serious as some think.

    Opps, my 2 year old just opened a bottle of glue – gotta go.


  3. One last comment:

    Barton is talking now. He is going on saying that this challenges global warming – we need the facts – bringing up Newsweek 75, etc.

    Gotta go – taking the kids swimming!


  4. On your first point about von Storch’s views, the Today programme on Lovelock’s book (as discussed by JA here) had vS on the panel which gave unanimous agreement to the following statements (caveated in the comments on JEB):

    * It is likely that temperatures will rise by 3C to 5C by the year 2100 unless we act swiftly to cut greenhouse gas emissions and protect natural forests.

    * Temperatures might rise by as much as 8C by 2100, but this is less likely.

    * A temperature rise of 3C to 5C would probably bring severe changes for humans.

    * Climate change is real, dangerous and significant in our own lifetimes.

    On your final point about code documentation, it’s a general problem in IT in all areas for maintained code’s documentation to quickly get out of date. Some people even advocate not using in-code comments because of their tendency to fall behind what the actual code is doing. There has been some academic work in the idea of programming by documentation (see Z) and some practical work on automating code generation from documentation, but this is not widespread and tends to be used for first cut. So it would not be surprising to see the problem in climate models, either. Some of the code at the Met Office I’ve seen (from the 70s/80s), though very cleverly written, was at times, rather like the trying to decipher Linear B (or even Linear A at times)…that code was all replaced BTW.


  5. Thanks, John Cross, for the play-by-play. By the way, do you know if there is any way to get hold of the video/audio from that hearing? I know they had a link up at the Committee website as a live feed…but I figured it also ought to be available to see after-the-fact. Unfortunately, I can’t for the life of me find where. They just seem to have removed the link once the hearing ended. (I know that the prepared statements submitted in advance are available at the Committee website…but I wanted to see the Q&A.)


  6. Thanks, John! I could swear that is where I was looking yesterday and the link wasn’t there. But, anyway, it’s there for me now!


  7. I could care less if VS thinks that GW is occurring. I don’t want bad evidence that is in the skeptic camp or in the warmer camp. I think the skeptics who tout weak evidence are weak reeds. I also think the “scientists” who are defensive and won’t admit errors ala Mann are weak as well. Dick Feynmann would crap all over them.


  8. “Philosophy. Richard Feynmann liked to remind us how science works. We must continually question our conclusions, presenting all sides of an argument equally, and changing our conclusions when the evidence warrants it.

    “I have been told that my discussion (Hansen, 2004) is too critical of IPCC. This, I believe, is a misreading of the spirit of my discussion. I aim to be no more or less
    critical of IPCC than of my own papers.”



  9. William … of course your BAS ice core mates are obligated to share their data with the academic community by virtue of the NERC data policy … after a suitable period.

    … but that’s not the purpose of my comment. Just to say that there are a number of activities under way to improve the documentation of numerical model codes along the lines described. Check out http://proj.badc.rl.ac.uk/ndg/wiki/NumSim and the link to the Numerical Metadata project at NCAS/CGAM which is linked from there.


  10. >No names, but a harsh criticism of somebody.

    who could that be ???

    So far, it has been astonishingly bad news for MBH. If I recall correctly, the good prof north said that he agreed with the statistical criticisms made by wegman against MBH, and I heard no dissent from that view in the evidence.

    There was also extensive comment, including by North for the NAS panel, on how important it is to share data and methods- a major shortcoming of MBH.

    Given the rather amazing attitude of Mann, as judged by his comments about M&M, it is pretty stunning to see M&M vindicated by the NRC and a congressional committee.

    I for one am looking forward to the good dr mann’s appearance before the committee.



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