Robert M. Carter, et al write,

peer review is both too inbred and insufficiently thorough to serve any audit purpose, which we believe is now essential for science studies that are to be used to drive trillion-dollar policies.

The authors (dismissed as “the usual suspects” by global warming believers) make a case that climate models are not mature. Concerning the Stern report, the authors write,

The Review assumes, against all empirical evidence and physical reasoning, that future increments of CO2 will have substantially greater effects than those in the past.

Ian Byatt, et al (same link, further down) question the economic cost estimates of Global Warming in the Stern report.

The Review then positions itself as an outlier by…dramatically ramping up estimates of damages due to extreme weather, ‘social and political instability’, and ‘knock-on effects’…The latter two…are grouped into ‘nonmarket impact’ and ‘risk of catastrophe’ effects, though with little further definition provided. According to the Review, they account for some 80–90 per cent of the projected damages due to global warming, and yet everybody else seems to have missed them.

I pass this along with a caveat emptor label. The reader who sent me the link pointed out that Robert Skidelsky, author of the superb biography of Keynes, is a co-author in the economics section. Other than that, I cannot vouch for the reputations of any of the authors, nor do I have expertise on the content. As you know, I am skeptical about climate models.