I am struck by the difference between their (large) single - forcing uncertainties and that for the aggregate historical run, which is very small. (climateaudit.org)
The GCM model performance in warming in minimum temperatures through the long historical runs is not good at all. (realclimate.org)
James, The simulations they use for evaluating their method are 1 % per year CO2 increase, not historical runs with spatially diverse forcing. (julesandjames.blogspot.ru)