Environmental economist, Frank Ackerman, has produced a detailed commentary debunking denier darling, Richard Tol's, economics of climate change literature review to which the IPCC AR5 WG2 report referred heavily.
The Economics for Equity and the Environment Network blog features an excerpt of the commentary, but the even shorter version is that Tol botched his analysis, chose his sources poorly, and misrepresented other sources (for example, Ackerman states that his work was misinterpreted by Tol.)
This is a particularly brave rebuttal considering that Tol previously attacked Ackerman, accusing him of libel and even contacting Ackerman's employers. See Rabbet Run for more.