Richard Tol is a professor at both Hamburg and Carnegie Mellon Universities, and is one of the world's leading environmental economists.
The Stern Review cites his work 63 times; but that does not mean he agrees with it.
"If a student of mine were to hand in this report as a Masters thesis, perhaps if I were in a good mood I would give him a 'D' for diligence; but more likely I would give him an 'F' for fail...
Professor Tol believes the figures for damage are exaggerated.
"Stern consistently picks the most pessimistic for every choice that one can make. He overestimates through cherry-picking, he double counts particularly the risks and he underestimates what development and adaptation will do to impacts," he said...
Professor Mike Hulme, director of the Tyndall Centre for Climate Change Research, believes that when the IPCC report comes out next week, there will be a big difference between the science it contains and the climate debate in the UK.
"The IPCC is not going to talk about tipping points; it's not going to talk about 5m rises in sea level; it's not going to talk about the next ice age because the Gulf Stream collapses; and it's going to have none of the economics of the Stern Review," he said.
"It's almost as if a credibility gap has emerged between what the British public thinks and what the international science community think."