In May 2005, I mentioned Hwang et al. [Science 2005], now at the center of a firestorm. This reference was entirely by chance, since my concern was the precipitous UCAR press release of the Ammann and Wahl paper and their failure to report its subsequent rejection. (Of course, they later got the editor changed and got the rejected paper out of the garbage can, but that’s a different story.) In the process, I noted up a Nature editorial in which they criticized the issuance of a press release merely upon the submission of an article without waiting for the imprimatur of peer review. It’s amusing to re-read in the light of the Hwang firestorm. Continue reading →
A science scandal of Bre-X proportions has been developing through December engulfing both Science and Nature. New developments on Hwang’s stem cell research have been occurring daily. Hwang, like Mann, was one of Scientific American’s 50 Visionaries. Unlike Mann, he has been stripped of his title. I started looking at the story from a peer review point of view, but I find scandals interesting and have spent a few hours trying to make a chronology. Pending that, I’m posting up a few links and commenting on the fact that blogs were responsible for Hwang’s downfall – even though one of Science’s editors is spinning the story as a triumph of peer review. However, the following is a more accurate attribution of credit for exposing Hwang:
It was a group of young Koreans scientists who assiduously brought all the charges to light, posting their criticisms of Hwang on a Web site.
For background, I am a supporter of stem cell research and disagree strongly with Bush policies on this topic. Continue reading →
There is an interesting controversy at Nature and Science about peer review in the context of Hwang’s stem cell research (google for links.) I’m going to post a comment about this in light of my own experience with both. First, I want to post some information (courtesy of a reader here) about archiving policies at the Journal of Political Economy. For paleoclimate studies, there is absolutely nothing intrinsic to the subject which prevents the implementation of similar policies by Nature or Science as a “best practices” standard. In my view, the focus of invetigation by the two journals in respect to Hwang is not about “peer review” in the abstract, but whether the journal policies meet “best practices” standards. Continue reading →
Some seasonal remarks – a few substantive and a few personal. Continue reading →
I posted up on Kaufmann and Stern [2005] on GCMs a few days ago. Kaufmann subsequently posted up at realclimate here about this, with a detailed reply from Gavin. The exchange is interesting on a number of levels – there is an interesting statistical point raised. In addition, you will notice how quick Gavin is to try to move what was quickly becoming a "serious" discussion offline, perhaps so that the hoi polloi aren’t involved. Continue reading →
Let’s look again at what Rasmus was saying before Gavin sent him to the end of the bench. He argued that Cohn and Lins were sucking and blowing by calibrating the autocorrelation on instrumental records, which themselves contained a trend. Gavin endorsed this position. On the face of it, this seems like a plausible criticism. However, this is not what Cohn and Lins either did or said. (One of the irritating features of realclimate authors is that they seldom quote directly from their adversaries and frequently set up straw men. You always have to check their characterizations. I try to avoid the same problem by quoting extensively as much as possible.) Continue reading →
In response to a few complaints, I’ve expanded the recent comments from 5 to 10, because we now have them coming so thick and fast that some people (rather sad people in my view) are missing responses to comments.
Of course the ultimate solution for those scientists out there who claim to be addicted to Climate Audit (and you know who you are) is to use an RSS reader and use the URLs at the bottom of this page. In fact, users of Firefox can cut-and-paste the RSS links into their bookmarks and set them to update every half an hour.
In other news, I’ve been installing a cut-down version of LaTeX which means that Steve will be able to produce some pretty equations in his text.
For example:
is the Navier-Stokes equation of incompressible fluid flow where 
is the kinematic viscosity , 
is the velocity of the fluid parcel, 
is the pressure, and 
is the fluid density
It’s a little unwieldy to create at the moment, so I have to get into the guts of the WordPress system to make it easier to create equations.
Nothing from Rasmus for over a day; it’s all Gavin now. Soon it will be “sigh….” and they’ll put the figure skaters back on the ice. We want hockey, not sequins. We want Rasmus, we want Rasmus, we want Rasmus… Is Rasmus in lock-up? Should we start a petition for Gavin to free Rasmus? Free Rasmus now, free Rasmus now, free Rasmus now….
Rasmus, if Gavin won’t let you off the bench or is censoring you, you can always post here. We’ll be nice.
Kaufmann and Stern contained a reference to the provocatively titled Govindan et al. [2002], Global Climate Models Violate Scaling of the Observed Atmospheric Variability, Phys. Rev. Lett. 89, available here . I’ll comment at some time on the scaling issues, but it contained the following concise description of GCMs which I liked:
The models [coupled atmosphere-ocean general circulation models (AOGCMs) ] provide numerical solutions of the Navier Stokes equations devised for simulating mesoscale to large-scale atmospheric and oceanic dynamics. In addition to the explicitly resolved scales of motions, the models also contain parametrization schemes representing the so-called subgrid-scale processes, such as radiative transfer, turbulent mixing, boundary layer processes, cumulus convection, precipitation, and gravity wave drag. A radiative transfer scheme, for example, is necessary for simulating the role of various greenhouse gases such as CO2 and the effect of aerosol particles. The differences among the models usually lie in the selection of the numerical methods employed, the choice of the spatial resolution, and the subgrid-scale.
Note carefully the focus on Navier-Stokes equations, which are notoriously intractable with very difficult mathematics. In fact, they are one of the Clay Insitute’s seven "Hilbert" problems for the 21st century – a $1 million prize is attached to any progress on the mathematics of the Navier-Stokes equations. So one should not assume that brute force numerical methods necessarily evade difficult and subtle mathematical problems. Continue reading →
I have much unfinished business with multiproxy studies, but am getting dragged into discussing GCMs, where I wish to make clear that I am not familiar with the literature and am merely commenting on individual articles as I read them in the context of current discussion. If I miss some nuance, I apologize and will try to correct. Rasmus observed here that:
the most appropriate null-distributions are derived from long control simulations performed with such GCMs. The GCMs embody much more physically-based information, and do provide a physically consistent representation of the radiative balance, energy distribution and dynamical processes in our climate system.
Kaufmann and Stern [2005], A Statistical Evaluation of GCMs: Modeling the Temporal Relation between Radiative Forcing and Global Surface Temperature here consider the interesting qustion of whether GCMs out-perform elementary statistical models, given the same inputs, and come to very negative conclusions about GCMs and even question whether GCMs are an appropriate tool for assessing the issue of global temperature change (as opposed to regional impacts.) They say:
none of the GCM’s have explanatory power for observed temperature additional to that provided by the radiative forcing variables that are used to simulate the GCM…
Curiously, Kaufmann weighed in at realclimate in a thread which was specifically discussing the utility of GCMs for making null distributions, but did not mention this article, instead mentioning some of his other work purporting to show cointegration between CO2 and global temperature change. In passing, I might observe once again that a GCM step of 25 years takes 1 calendar day. To obtain a null distribution of 1000 runs of 25,000 years (still less than 1 obliquity cycle) is well beyond the range of present computing power. So the "null distributions" that Rasmus is talking about are not "null distributions" as they are understood in statistics, where 1000 would be a bare minimum. Anyway on to some excerpts from Kaufmann and Stern. Continue reading →
Climate Audit 