This is a very important number, and probably the most relevant number as we progress into the 21st century, but paleoclimate studies are primarily focused on the equilibrium response (i.e., after the oceans have warmed up sufficiently to allow the top of atmosphere radiative budget to be balanced). (realclimate.org)
Referring to Chris»: ``... only similar in that regions above the tropopause are typically optically thin enough to not matter much for the net radiative budget...» (realclimate.org)
It is concluded that atmospheric feedback diagnosis of the climate system remains an unsolved problem, due primarily to the inability to distinguish between radiative forcing and radiative feedback in satellite radiative budget observations. (thenewamerican.com)