This is so disappointing: James Randi joins the ranks of the climate change denialists, and he does so on the basis of an extremely poor argument. I know, he’s a professional skeptic about everything, but skeptics must have some standard for evidence … a standard which the climatologists have reached, while the denialists have not. Here’s the core of Randi’s dissent from the scientific consensus.
I strongly suspect that The Petition Project may be valid. I base this on my admittedly rudimentary knowledge of the facts about planet Earth. This ball of hot rock and salt water spins on its axis and rotates about the Sun with the expected regularity, though we’re aware that lunar tides, solar wind, galactic space dust and geomagnetic storms have cooled the planet by about one centigrade degree in the past 150 years. The myriad of influences that act upon Earth are so many and so variable — though not capricious — that I believe we simply cannot formulate an equation into which we enter variables and come up with an answer. A living planet will continually belch, vibrate, fracture, and crumble a bit, and thus defeat an accurate equation. Please note that this my amateur opinion, based on probably insufficient data.
At least he’s self-aware enoughto realize that he has come to this conclusion on the basis of his personal ignorance. He has two main reasons otherwise to disagree with the idea of anthropogenic global warming.
One is the idea that climate is such a complex product of multiple phenomena that we should expect significant variation, and that no one could possibly have a single equation that describes it all. This is entirely true, but irrelevant. Climate scientists have collected a huge amount of data, and the confounding fact that none of them would ever deny is that it’s variable, messy, noisy stuff, with loads of daily/monthly/yearly variation, and it has to be analyzed to find long term trends. The consensus was not reached because somebody had a magic formula that predicts a result. It was reached because a body of observation has shown long term change is going on. They are aware of possible causes, and they know that phenomena like volcanic eruptions and cyclic changes in solar activity effect climate…and our situation is not sufficiently explained by those kinds of natural events. One consistent change is a rise in CO2 levels, and we know that we are digging up huge reservoirs of sequestered carbon and dumping it into the atmosphere.
The other source of his skepticism is one that Randi should have been more skeptical about: the Petition Project. This is a project by the denialists to gather enough signatures to show a strong pattern of dissent in the scientific community (Sound familiar? The Discovery Institute has done exactly the same thing with their “Dissent from Darwin” list). They’ve got over 30,000 signatures so far! However, as with the Discovery Institute’s list, only a tiny proportion of the signatories are actually qualified, and their procedure for gathering signatures is incredibly sloppy and prone to accumulate fake names. This is what you’d expect: they don’t want quality control, for the propaganda purposes of this list, all you need is quantity.
The source for this list is also rather dubious. It comes from a tiny team of crank scientists operating out of a ‘think tank’ in a small town in Oregon.
I would expect Randi to have given his denialist sources the same degree of critical analysis that he gave to the conclusions of the IPCC. Maybe he did, since he has shown no understanding of the IPCC determinations at all, but I think it was a gross mistake on his part to therefore charge in and decide on the basis of his rudimentary knowledge that maybe the fringe cranks were right.

