The idea behind the discussion of
vertical stability vs horizontal stability is, that
in most sporting activities, such as running, jumping, hitting, kicking,
etc the athlete is
in an upright
position and has to fight the forces of gravity.
First, for changing just CO2 forcing (or CH4,
etc, or for a non-GHE forcing, such as a change
in incident solar radiation, volcanic aerosols,
etc.), there will be other GHE radiative «forcings» (feedbacks, though
in the context of measuring their radiative effect, they can be described as having radiative forcings of x W / m2 per change
in surface T), such as water vapor feedback, LW cloud feedback, and also, because GHE depends on the
vertical temperature distribution, the lapse rate feedback (this generally refers to the tropospheric lapse rate, though changes
in the
position of the tropopause and changes
in the stratospheric temperature could also be considered lapse - rate feedbacks for forcing at TOA; forcing at the tropopause with stratospheric adjustment takes some of that into account; sensitivity to forcing at the tropopause with stratospheric adjustment will generally be different from sensitivity to forcing without stratospheric adjustment and both will generally be different from forcing at TOA before stratospheric adjustment; forcing at TOA after stratospehric adjustment is identical to forcing at the tropopause after stratospheric adjustment).