PDF file (Lindzen's article; Rahmstorf's semi-reply; Lindzen's response)
This exchange is kind of interesting because both participants are highly regarded figures in climatology and they approach the problems as physicists.
Funny or scary interruption: two days ago, I wrote that I was hoping that Al Gore and the alarmists wouldn't try to realize their goal about the "consensus" by explosives directed against New York's Times Square. Today, a small explosion rocked Times Square. Witnesses from the Marriott Marquis hotel described their perceptions.Still, you can see that that quantitative and rational evaluation of reality has its limits in the case of the climatic hot head (Stefan Rahmstorf). On the other hand, the climatic cool head (Richard Lindzen) is able to estimate the likelihood of various models scientifically even if the conclusions look sensitive politically.
He knows how to use Occam's razor and how to compare the likelihoods of contrived explanations with many assumptions (an effect is strong; it is masked at many places where we could observe it; etc.) and natural explanations without any excessively special assumptions.
Sometimes, the bias is far too obvious. For example, whenever Rahmstorf talks about the natural effects influencing the climate, he says that they are "masking" the man-made global warming. Such a language trick is equivalent to an unjustified, propagandistic assumption about the sign of an effect and it is very clear that once he formulates a hypothetical explanation in this way, it can't be studied scientifically because its very essence is a dogma. In reality, many of these effects can have - and probably do have - the opposite sign than Rahmstorf implicitly assumes (including the total feedback of the clouds or the regulating effect of the oceans).
Commercial: John Tierney of the New York Times wrote a rather deep and comprehensive analysis of the financial and other motives of scientists and people around science, including government officials and corporationsRahmstorf, a former general relativist, is not quite stupid but some of his comments are sort of incredible. For example, he argues that the consistency of a model with the historical data shouldn't affect our confidence in these models. He offers a lot of minor technical errors, for example arguing that there was no El Nino in 2005 (although an El Nino episode ended in JFM 2005); that AGW used to be outlandish decades ago (compare with the 1958 movie we discussed recently).
Rahmstorf also makes a typically layperson's mistake when he thinks that the climate sensitivity can be measured "directly" without having any theory or model in mind. Incredibly, he seems to be using "fingerprints" as evidence for the greenhouse theory of the climate, even though the theoretical fingerprints clearly disagree with the reality.
Richard Lindzen also doesn't buy Rahmstorf's bizarre comparison of climate science with general relativity (and their trustworthiness, including an identification of relativistic crackpots with climate realists), emphasizing how troubled Einstein was because of a single parameter (the cosmological constant) while the consensus climatologists don't seem to care about dozens of important yet unverified adjustable parameters, fudge factors, and other arbitrary assumptions in their models.