I think the case for climate skeptic is a bit overblown. In his own words:
http://archive.randi.org/site/index.php/swift-blog/806-i-am-not-qdenyingq-anything.html
The relevant quote:
My remarks, again, are directed at the complexity of determining whether this GW is anthropogenic or not. I do not deny that possibility. In fact, I accept it as quite probable.
Not sure what to make of the claim that he debunked people who never signed up for his challenge. There are a number of psychics and others that he has debunked that never signed up for the challenge (for example Uri Geller or Sylvia Browne) which this could be referring to, and I feel are valid debunking.
Illiterate, or maybe autistic and prone to reading things literally until someone mentions that it’s an allegory at which point it all snaps into place and makes sense.