I have sympathy for the authors of the letter to the WSJ because of the attitudes of people like you. I'm an free thinking, rationally minded, individual. I value my right and capacity to evaluate arguments on their merit and to question the factual basis of other people's assertions. When people jump down my throat and call me a sophist, a "denier", and imply that anything I say must be preconceived notions that I have swallowed whole from some fossil fuel industry shill, all because I presumed to point out something that appears to be erroneous in someone else's statement, it irritates me.
The proposition I was testing (in a totally back of the envelope way) was that the temperature record of the past decade shows evidence of warming. I tested this particular proposition, not because I was hand picking data, but because the poster I responded to had suggested that the truth of this proposition was blatantly obvious. It did not seem so to me, and I believe that my quick calculation verified that intuition. Other than that I did not deny anything.
I specifically said "your argument provides good evidence that the past decade has been significantly warmer than other decades in the past 130 years". That is, a clear longer term warming trend exists. I also noted that "one could definitely argue that this does not constitute evidence against global warming". Which is exactly what you are doing.
I would argue however that the vehemence of your reply displays an attitude that is both characteristic of many people who urge action on reducing carbon emissions (something I support) and antithetical to the scientific mindset. There is much evidence that a person's preconceptions can have a significant impact on the outcome of their research, even with seemingly cut and dried empirical work like measuring the charge of the electron. The potential for bias induced error is undoubtedly much greater in a theoretical and speculative investigation like climate modeling, in which many important variables can only be roughly estimated. Combine with that potential the very real and evident passion displayed by many people who are involved in the research and you have a formula for bad science.
I have degrees in physics and economics. Physics draws conclusions from repeated experiments under carefully controlled conditions. Economics must rely on theory and limited data run through sophisticated econometric models, because the systems under consideration are not subject to control and repetition. Economists try to tease answers from our limited data. Answering a question like "Was the recent stimulus bill effective in promoting economic growth?" is not easy. Ideally we would set up the exact conditions of the U.S. in 2008 and try several runs with the stimulus bill and several without, then compare the results. That, unfortunately, is not possible. One can try to answer the question using mathematical models and computer simulations but the conclusion depends on how you handle your data and set up your model. Indeed, none of the models are able to predict the future trajectory of the economy with accuracy. Which is what I think the authors were getting at. If the climate models are so completely accurate that no reasonable person could possibly question them, then why did none of them predict flat global average temperatures over the past decade? If they're not that accurate, then why are people who ask seemingly reasonable questions about them insulted and shouted down?
I would suggest that climate modeling is much more similar to modelling the economy than to modelling, say, the trajectory of a space capsule. The problem of studying global warming is far more complicated than that of studying the impact of smoking on cancer rates. If we had data on the fates of thousands of Earth-like planets, some of which had been inhabited by carbon emitting civilizations and others not, the analogy would be apt. We could draw a strong statistical conclusion and act on it.
I am not however suggesting inaction. In the absence of conclusive evidence we must still make decisions. It seems obvious that we ought to act in a risk averse way when making decisions about the environment upon which we depend for our continued existence. So, by all means, let us do everything we can to protect the environment given what understanding we can muster (just as we need to formulate economic policy as best we can given our uncertainty).
You should look to your own preconceived notions. While insulting me you manage to suggest that I made many assertions that I did not while pretty much completely ignoring the simple and innocuous point that I did make.
Scientific progress consists almost entirely in people questioning each others data, methods, assumptions etc. That's almost the entire point of peer review. How can we improve our knowledge of the environment when anyone who says anything that even comes close to seeming to question the current consensus is subject to recriminations, name calling, and accusations that they are an enemy of humanity? How can we protect the environment if we can't take the steps necessary to understand it?
Say someone told me that the consensus of economic forecasters was that the U.S. economy will grow by two percent this year. And I replied "no, I believe that they underestimate the potential impact of trouble in European bond markets, I think growth will probably be closer to zero this year". Then my conversational partner responded with recriminations, name calling, and accusations that I was clearly evil and unpatriotic. Wouldn't that be weird?
I think many of the supposed "deniers", should probably just be called questioners. They are people who, like me, posses that perverse sort of irresistible curiosity that, when told "don't ask questions!", immediately respond by asking "why?" All scientific conclusions come with a degree of uncertainty, and climate models more than most. I think that some environmentalists fear that the public can't deal with uncertainty. They fear (perhaps reasonably) that, unless the disastrous warming conclusion is seen as being 100% certain, people will never get behind an effort to curtail carbon emissions. So a taboo has evolved such that it should be considered intolerable for anyone to question the science around global warming (to the likely detriment of our actual understanding of the Earth's climate). What should be regarded as a reasonable and well supported scientific theory has taken on the character of dogma, with anyone who questions the party line being subjected to ostracism and ad hominem attacks (see above).