Here is an excerpt from his paper:
There is much in the Stern report with which one can wholeheartedly agree. Climate change is a problem. Climate policy can be informed by cost benefit analysis. The treatment of uncertainty is of paramount importance and economic instruments have a role to play in cutting carbon emissions. Permitting tropical deforestation is madness. But the review also contains errors, questionable judgement and inconsistencies. Stern moreover misses the opportunity to say some things which needed to be said. There is often insufficient information to discover what Stern and his team have done and how they arrive at key results. It would currently be impossible for another researcher to replicate Stern’s findings for sheer lack of information. Some of the evidence upon which the review is based is dated whilst more recent evidence has been overlooked. The Stern review should have been subject to far more extensive peer review prior to its release, particularly in the light of its political impact.