As a physicist, I can state that none of the 18 physicists who signed the Statement works in this field; nor to my knowledge has ever published a paper on this subject.
However, the models also predict unambiguously that the atmosphere is warming faster than the surface of the earth; but all the available observational data unambiguously shows the opposite!
It is disappointing and embarrassing to the science profession that some Nobel Laureates would deliberately use their well deserved scientific reputations and hold themselves out as experts in other fields.