This post is incomplete a full post will be appended, below is a comment I made on another blog
I was researching climate sensitivity for a post on my blog when I came accross your site.
I have scanned most of your climate pieces and in principle I am in agreement with all of your conclusions. My newpiece not yet published will make the following claims.
The IPCC sensitivity given in Wikipedia is erroneous.
(‘The computed climate sensitivity is therefore 5/7.1 = 0.7 K(W/m2)−1. We can use this empirically derived climate sensitivity to predict the temperature rise from a forcing of 4 W/m2, arising from a doubling of the atmospheric CO2 from pre-industrial levels.’) which predicts temp rise of 3 degC
My Initial analysis.
During glacial epochs the climate sensitivity alters and is at its highest during transitions between glacials/interglacials when it approaches 1 and is > 0.5 during 90 kyr glacial phase.
Prior to 1 Myr climate sensitivity was <0.5 and prior to 3 Myr climate sensitivity was =/<0.2. This can be gleaned by critically examining the 5 Myr temperature graph on Wikipedia. Examination also shows that temperature sensitivity increases after the Vostok equivalent temp falls below 0 degC and I believe is related to ice sheet dynamics. It is also probable that above 0 deg C VEq C02 controls the sensitivity, such that rising C02 levels will reduce climate sensitivity to <0.1 and will oppose forcing from other sources.
Also since the younger dryas total climate sensitivity seems to have stabilised at < 0.2 which would gives a a temp rise of <1 deg C for C02 doubling.
These calculations are based on an unrepeatable experiment recorded in ice cores and rocks. The earth itself is the most accurate GCM