The concept of CO2 greenhouse saturation is bullshit. All of the IR radiated from the Earth into space does so from the upper stratosphere. The elevation of that layer rises and falls with temperature. As the greenhouse effect drives up the Earth's temperature, the altitude of the radiating layer gets higher and higher. There is no saturation effect.
Is the CO2 effect saturated?
Never said anything about "saturation effect", it is the mathematically derived CO2 sensitivity is what matters here. For
each doubling CO2 warm forcing increase
gets smaller and smaller. Keep in mind that CO2 absorbs only a small part of the outgoing OLWR, in the first place.
Here is a recently published science paper showing this, from
SPRINGER LINK:
Infrared Atmospheric Emission
Boris M. Smirnov
First Online: 30 August 2016
Abstract
Emission of a flat layer, consisting of a gas with a weakly varied temperature in the perpendicular direction to the layer, is reduced to the case of the layer with a constant temperature. The average optical thickness of the Earth’s atmosphere in an infrared spectrum range is u≈2.7'>u≈2.7u≈2.7 and is determined on the basis of the energetic balance of the Earth and its atmosphere within the framework of the standard atmosphere model due to emission and surviving of infrared photons. It is shown that infrared emission of the atmosphere is determined mostly by atmospheric water. One can separate the flux of outgoing infrared radiation of the atmosphere from that towards the Earth. The fluxes due to rotation-vibration transitions of atmospheric CO2'>CO2CO2 molecules are evaluated. Doubling of the concentration of CO2'>CO2CO2 molecules in the atmosphere that is expected over 130 years leads to an increase of the average Earth temperature by (0.4±0.2)'>(0.4±0.2)(0.4±0.2) K mostly due to the flux towards the Earth if other atmospheric parameters are not varied. Various models with a water change give the temperature change (3.0±1.5)'>(3.0±1.5)(3.0±1.5) K at doubling of the CO2'>CO2CO2 molecule concentration. An observed temperature change (0.8∘C'>0.8∘C0.8∘C) during the industrial epoch may be realized if approximately 0.5%'>0.5%0.5% of free water molecules become aerosols, and this testifies to an atmospheric instability.