On Friday, April 3, 2015 at 10:06:32 PM UTC+1, Togless wrote:
"Alastair" wrote:
On Thursday, April 2, 2015 at 6:15:08 PM UTC+1, Togless wrote:
"Alastair" wrote:

It is the heat flow through the atmosphere that I say is
being modelled incorrectly. Absorption in the CO2 bands
is saturated, see Zhong and Haigh (2013).

True at the surface, but increases in atmospheric CO2 do reduce OLR to
space
at the top of the atmosphere, and the effects percolate down through the
atmosphere, warming the surface.

If the absorption is saturated at the base of the atmosphere then
there is no radiation for CO2 to reduce at the top of the atmosphere.

There is, because the whole atmosphere radiates in the infrared.

Yes, you are quite right. (Just testing you :-)

What I should have written is that, like the radiation at the base of the atmosphere, the outgoing radiation at the top of the atmosphere is saturated.. So increasing the concentration of CO2 raise the height from which the radiation emitted. It is argued that since it is coming from a greater altitude in the troposphere it will be at a lower temperature and so decrease. But it will still also be made up of emissions from the stratosphere, mesosphere which will increase because the CO2 there is denser. Moreover, the CO2 band is already attenuated. Decreasing a small amount results in a small decrease.

But that is not how it works. The clue is in your term "percolates down". The change in TOA OLR can be rectified if the TOA warms. There is no guarantee/mechanism to ensure the surface warms because the TOA cools.

I don't think I have really answered your objection, but thanks for raising it. It is the weak point in my theory which I must address.