Partha Dasgupta, professor of economics at the University of Cambridge and author of "Discounting Climate Change"  in Review of Environmental Economics and Policy:
"Unfortunately, Lomborg's thesis is built on a deep misconception of Earth's system and of economics when applied to that system. . . If the uncertainties are not small, standard cost–benefit analysis as applied to the economics of climate change becomes incoherent . . . "
Review of "Cool it!" in Nature 449, 143-144 (13 September 2007) (link)

P. Z.. Myers:
"And, as usual, he turns his false dilemma into an argument that we need to sit and talk about what to do, instead of actually doing anything. That's probably my main gripe with Lomborg: he's a clueless force for inertia, who's answer for everything is to do nothing that might cause us to break a sweat." Biologist P. Z. Myers in this blog.

Michael Pawlyn, after having made a phone call to one of Lomborg´s sources for the cost of climate damage:
"The figure that Lomborg has used was quite simply wrong and not just slightly wrong but by more than an order of magnitude. The figure that he has used to persuade thousands of influential people is a grotesque distortion. Just staggering." (link).

Michael Pawlyn:
"I phoned up one of the directors fo the World Glacier Monitoring Service and I said "What do you think of Bjorn´s statements about glaciers" and he said, well, the fact of the matter is the data simply does not support his statements. I then phoned one of the authors of the polar bear report who was really pretty fed up actually with the way that Bjorn had used not only out of date information, but had completely distorted the conclusions of the report." (link).

Howard Friel:
" As one reads on, one might wonder how Lomborg´s work managed to evade serious scrutiny by the major publishing houses . . . that issued his two major books . . . "  The Lomborg Deception, p. 6.