Flannery, page-52

"more and more CO2" and other GHGs are constantly being added.

you seem to mistake the effect of accumulated GHGs. its exponential rather than logarithmic. logarithms depend on the values applied. its not a blanket term which removes the effect.

also you're putting a spin on the whole that seems to come from those anti-AGW sites. if you can provide an explanation of this from a legit physics site, I'll consider such and double check, but what you've got here in unsubstantiated.