Comment on Hiding the Decline: Part II by Ferdinand Engelbeen

According to Modtran, the direct effect of 2xCO2 is 0.9°C. With water vapour feedback (quite sure for the lower troposphere, but absent where it matters: at the tropopause) it is 1.3°C.
For 40 ppmv CO2, the effect is about -0.3 to -0.4°C, not measurable within the accuracy of the ice cores.
If one takes the official range: 1.5-4.5°C (or beyond), the average at 3°C is borderline measurable, everything higher is measurable, but not measured… Thus all doomsday scenario’s based on a high sensitivity for CO2 can be trashed.