As someone who’s always had a great deal of respect for skeptic James Randi, I was disappointed to read his piece at the JREF Swift Blog: AGW, Revisited.

Randi cites the Petition Project (a bogus list of “skeptical scientists” packed with ringers, frauds, and people who never even signed it) as one of his main reasons for doubting the reality of global warming:

The Intergovernmental Panel on Climate Change (IPCC) — a group of thousands of scientists in 194 countries around the world, and recipient of the 2007 Nobel Peace Prize — has issued several comprehensive reports in which they indicate that they have become convinced that “global warming” is and will be seriously destructive to life as we know it, and that Man is the chief cause of it. They say that there is a consensus of scientists who believe we are headed for disaster if we do not stop burning fossil fuels, but a growing number of prominent scientists disagree. Meanwhile, some 32,000 scientists, 9,000 of them PhDs, have signed The Petition Project statement proclaiming that Man is not necessarily the chief cause of warming, that the phenomenon may not exist at all, and that, in any case, warming would not be disastrous. …

I strongly suspect that The Petition Project may be valid.

This, of course, was akin to a bomb being dropped in the middle of the “skeptical community.” And naturally, I immediately received several emails (some more polite than others), gloating over Randi’s “debunking” of global warming.

I held off writing about it because I knew Randi’s associates would soon be setting him straight on the deliberately deceptive Petition Project and his other misinformed claims, and sure enough, Phil Plait had a very good post yesterday: Randi, skepticism, and global warming | Bad Astronomy.

Yesterday, James Randi posted an entry on the JREF’s Swift blog about global warming. In it, he expressed some doubt over the consensus that humans are causing global warming. He does not doubt that warming is happening, as he made clear, just the role of humans in that change.

Unfortunately, one source he used in his essay was the Petition Project. This was an attempt by global warming denialists to muddy the climate issue, and one that has been thoroughly trashed — it’s really just as awful as the similarly ridiculous, and just as thoroughly nonsensical, attempt by the Discovery Institute to get a petition by scientists who doubt evolution. Randi also made a claim about the complexity of global warming, and how difficult it is to model, casting some uncertainty on it. As he said, this makes it very difficult for someone not well-versed in the field to come to a well-informed decision on climate change.

Read Phil’s entire post, because he makes several other excellent points.

And Randi has now walked back his earlier post, as I expected, making it clear that he’s not denying the reality of global warming after all, and that he was mistaken to cite the Petition Project: I Am Not ‘Denying’ Anything.

However, I also recommend reading Orac at ScienceBlogs, for more on Randi’s second post: James Randi, anthropogenic global warming, and skepticism, revisited one last time (I hope).

PZ Myers also has some interesting comments: Randi responds.

The short version: even a noted skeptic like James Randi can be misled by the astounding amounts of confusion being fed into the national debate on global warming by special interest groups. Which makes it all the more important to try to cut through the noise and become educated about the actual scientific evidence — and that’s the reason behind my focus on this subject recently.