The glaring error in "Cool It," and the one that disqualifies the book from making a serious contribution, is that Lomborg ignores the main concern driving the debate. Incredibly, he never mentions even the possibility that the world might heat up more than 4.7 degrees. Although he claims IPCC science as gospel, in fact the scientific body gives no single "standard" estimate as its official forecast for this century's warming. Instead, the IPCC provides a range of up to 10.5 degrees -- more than double the number on which Lomborg bases his entire argument. (LINK)
My climate change scientist brother taught me long ago that stats like 4.7 degrees have a high degree of uncertainty, which means that they could not be that bad but equally they could be much much worse. And if so, we're in really big trouble. Consequences are too big to take the Lomborg gamble.
I have to admit though that I warmed to him a bit by the way he responded in this interview in Salon (LINK):
Interviewer: Don't you think it's kind of odd that the Bush administration invited [Michael Crichton] to the White House to talk about climate change?
Lomborg: They did? Yeah, that is weird.