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.
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.