Gordian Knot of Nonsense – Part 1. Rahmstorf and company strike again.

August 28, 2011

Rahmstorf and friends are at it again, but this time they have signed on a bigger fish: Michael Mann of hockey stick infamy.  Somehow it does not surprise me that this new serving of dribble comes to us via the Proceedings of the National Academy of Sciences.  Frankly, it grieves me to know that this is the state of the scientific culture in the US. 123

I will refer to “Climate related sea-level variations over the past two millennia” (Andrew C. Kemp, Benjamin P. Horton, Jeffrey P. Donnelly, Michael E. Mann, Martin Vermeer, and Stefan Rahmstorf, PNAS, 2011)  as KMVR2011.  This paper dishes up a third generation model relating sea level rise rate to temperature whose immediate ancestors are Rahmstorf’s 2007 model and Vermeer’s and Rahmstorf’s 2009 model.

With H being sea level and T being global temperature the models have evolved as follows.

Generation 1, form Rahmstorf’s 2007 “A Semi-Empirical Approach to Projecting Future Sea-Level Rise

Generation 2, from Vermeer and Rahmstorf’s 2009 “Global sea level linked to global temperature

And now, Generation 3, from KMVR2011


A cursory examination of equation I makes it plain the this new model is simply the cobbling together of  the VR2009 model (with a1 and Too in this model being the same as a and To  respectively in VR2009) with an additional term,  a2[T(t) – T0(t)], taken from Jevrejeva (GRL, 37, 2010).  KMVR2011 sum up the meanings of each term in equation I as follows…

The first term captures a slow response compared to the time scale of interest (now one or two millennia, rather than one or two centuries as in [VR2009]). The second term represents intermediate time scales, where an initial linear rise gradually saturates with time scale τ as the base temperature (T0) catches up with T. In [VR2009], T0 was assumed to be constant. The third term is the immediate response term introduced by [VR2009]; it is of little consequence for the slower sea-level changes considered in this paper.

 In Rahmstorf’s 2007 model linking sea level rise rate to temperature there were only two constants (a and To) that needed to be determined.  The 2009 Vermeer and Rahmstorf (VR2009) model went a step further with three constants (a, To, and b) that needed to be determined.  The new KMVR2011 model advances the science with four constants (a1, a2, Too and b).  Count them!  But even more astonishing: this model requires not just solving for the four constants, but also a time varying function (To(t) )!

Back at the keyboard

I have had a leisurely summer, and have not written any blog posts for several months, but my eyes and ears have been open, and my pencil has scratched out a few equations.   This post represents the beginning of a new series on KMVR2011, which I will call the “Gordian Knot of Nonsense.”

This series will be interspersed with posts on other topics, so please check back occasionally for updates.


  1. […] Sanity « Gordian Knot of Nonsense – Part 1. Rahmstorf and company strike again. Gordian Knot of Nonsensen – Part 2. A simple hypothetical temperature model September […]

  2. Dear Sir;
    My local county gov’t (California) is presenting a Energy Efficiency Climate Action Plan, which relies in some part on the
    ” These projections are from the State of California Sea‐Level Rise Interim Guidance Document
    which used the most up to date scientific projections from the Vermeer and Rahmstorf
    publication and further updated them to have 2000 as the baseline. ”

    I am wondering about the applicability of the prior criticisms ( imprudent extrapolation, ignored groundwater effects, etc.). What fraction of the issues have been addressed by the 2011 iteration?
    I must go to a public comment party tomorrow and would like to make informed questions.

    • RR,

      Thank you for the comment.

      If by “the 2011 iteration” you mean…

      ”Climate related sea-level variations over the past two millennia” (Andrew C. Kemp, Benjamin P. Horton, Jeffrey P. Donnelly, Michael E. Mann, Martin Vermeer, and Stefan Rahmstorf, PNAS, 2011

      then, they have not addressed any of the issues that I brought up. Instead they attempted to build a sea-level reconstruction going back 2000 years. However, the 2009 Vermeer and Rahmstrof model that I have been very critical of was used as a fundmental tool in building this reconstruction. So that brings their 2000 year reconstruction in to doubt also.

      Best Regards
      Tom Moriarty

      • Dear Sir;
        Thanks for the prompt reply.

        I imagine that my initial point of inquiry will be regarding their repeated claims that they rely upon VR2009, as ‘the most up-to-date scientific projections’.
        Clearly that fails with the 2009 Church and White data update. A factor of 2x is an easy ‘powerpoint’ headline.

        I don’t know how far into details I will get, given the artificiality of ‘Public Review’ meetings in CA.
        VR2009 errors regarding ‘mined ancient water’ might be my next point of discussion.

        The discussion might founder on the point that ‘The State of CA’ and an ‘Executive Order’ trumps any logic or errors. I guess I can still argue that their statement of pedigree is wrong on its face, without regard for Executive power. The data update is 2 years old, and has not been incorporated.

        I wonder about the part where they ‘updated’ the 1990 ‘forecast’ to 2000, by simply ~offsetting by 37mm. I need to check if the forecasts were higher than the actual data already.
        Thanks for all your clear writing.
        Very handy that you show all work.

  3. Well, I went to the meeting, albeit under suboptimal personal status. (Having been ill for a few weeks with flu-like bronchitis/pneumonia, I was/am still limited to clear broth and rice for nutrition.) Also, I had gastric endoscopy w/ ‘conscious sedation’ at 3pm, and spoke at the ‘public meeting’ at 7. So, I was not on top of my game, and my intended prep time was otherwise consumed.
    It was an odd setting, essentially ‘enviro-contractors’ and their employers (county gov’t workers). The theme of the night was some kind of ‘outreach to the hicks’, for the county’s Energy Efficiency Climate Action Plan. They were seeking ‘input’ for things to analyze for Climate Chance impact. Although the ‘Sea Level Rise’ element of their draft plan was pursuant to an Executive Order signed by Schwartznegger, they claimed that some other aspects (perhaps CO2 emission inventories) were a county initiative. They had done a world-class job of going through the motions on the CO2 inventory, carefully toting up very arcane subdivisions before dismissing the subdivided category as less than 1%.
    They concluded that transportation was more than 50% of the emission, and the presumed improvements in fuel efficiency were the dominant effect in their projections. At no point were the reductions tied to any future reductions in the projected temperature rises.

    Anyway, it was a rainy night, and I was the sole member of the public when I arrived. (Later I signed the ‘mailing list’ and was maybe the 10th person and last person to do so . They started packing while I was talking.I think there were ~6 contractors and 2 county employees.)

    As such, they were required to be nice to me, and make a show of listening. I maintained my best professional demeanor that I could muster under the circumstances, while explaining that the foundation for their Seal Level Rise analysis (VR2009) was without merit.

    I read this quote from the Journal of Coastal Research ” A recent workshop of the Intergovernmental Panel on Climate Change (IPCC, 2010) considered the semi-empirical approaches of Rahmstorf (2007), Vermeer and Rahmstorf (2009), and others and concluded, “No physically-based information is contained in such models …” (p. 2) and “The physical basis for the large estimates from these semi-empirical models is therefore currently lacking” (p. 2). ” .


    I stepped to the flipchart and drew my summary of your work. I contrasted the traditional plots of sea level vs time, with my understanding of the VR2009 method.

    I drew the graph of binned SLR accelerations vs. temperature, and said that VR2009 had simply fitted a slope to that scatter plot.
    I then drew the full inchworm/loop-de-loop version of the unbinned (but presumably smoothed?) acceleration data. The most satisfying part of the evening came when one of the contractors said “Wait, are you saying he plotted SLR acceleration vs. temperature?” This gave me the chance to apologize for not writing the units correctly on my hasty graph, but indeed units are mm per year per year. I wrote mm/ (Yr**2). I think I raised at least a brief moment of doubt in their confidence.

    I was unable to find my graph from Colorado, showing recent deceleration in the SLR. They seemed amazed, and were sure that local SLR was still increasing…

    After about 15 minutes, I had exhausted my scant reserves of coherence, signed in, and left. I then came back and suggested that the scantly attended recent ‘Waxman/Markey’ hearing was a harbinger for them, and that the leaked IPPC 5 position will emphasize natural variability, vs. monotonic deterioration.
    They folded the tent early and went back to their highrise building w/parking structure…
    I really appreciated the fine resource you created here, and hope I was able to correctly convey the essence.

    I did mention that VR2009 was not ‘the latest’, as it was calculated on the older Church and White data. They did acknowledge that they had overstated the degree to which VR2009 was ‘the latest ‘ science. My claims that VR2009 was halved with the latest data had no credibility.
    Best regards,

  4. Oh my, I see that I conflated two graphs in my post-procedural fog. The VR2009 graph with acceleration in the Y-axis, has time on the x-axis, and the loop-de-loop graph has rate vs. temperature.
    Thus I did overstate my case, just as they were doing. Sigh…
    I see that this now presents me the opportunity to ask someone there to connect me with someone who can ‘explain’ their ‘bedrock’ VR2009′ paper methodology to me with a straight face.

    Perhaps I have illustrated a problem for once-intelligent lay audiences to grasp your messages. To the extent possible, it might be good to make a summary post that captures the key points of the detailed analyses. For example, what is the net effect of ‘fitting’ the non-binned C&W (2006 and 2009 vintages) data using VR2009 methods.
    I wouldn’t have had the motivation to plow through all 12 chapters of the dissection in most situations, and a succinct summary might help others take the plunge (and get it right for that matter…)

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