The bunnies have been asking for some hints about the dance Dickie Tol is attempting. Ok, as Eli wrote over at Retraction Watch a couple of days ago (May 21)
What Tol is saying is that if one includes his outlier even with corrections the curve is rather banana like with a net positive benefit at modest warming. As Frank Ackerman has shown this is a result of the curious way in which Tol’s FUND model calculates agricultural effects, the positive benefit is large and completely different from every other study.
If you do not include the TolGiven that, Tol's statement that
and Anthoffresult, then you pretty much get a simple aX2 fit which is negative everywhere, rather than what Tol shows (see And Then There is Physics for a long discussion of this). If you force the fit using Tol’s data, then to encompass the other results the curve has to descend more rapidly past 3 C of warming taking into account the other models including the questionable Tol mode. This means that Tol’s fit predicts more damage at higher warming than the aX2 fit however, as the IPCC AR5 points out, Integrated Assessment models (IAMs) past 3C warming are economic fiction, because the damage would be so great and from so many directions not included in the IAMs that the models lose validity.
The assessment of the impacts of profound climate change has been revised: We are now less pessimistic than we used to be.is just parlor games. Neither old nor new are valid much past 3 C . But what does Eli know, he's only a bunny. Perhaps the good Professor Tol will accept the analysis that Andrew Gelman posted today