Instead, they discuss new ways of playing around with the aerosol judge factor needed to explain why 20th - century
warming is about half of the
warming expected for increased in GHGs; and then expand their
list of fudge factors to include smaller volcanos, stratospheric water vapor (published with no
estimate of uncertainty for the predicted change in Ts), transfer of heat to the deeper ocean (where changes in heat content are hard to accurately measure), etc..
I can understand that, since many times the
estimates of future effects of global
warming listed in previous reports have turned out to be underestimates.