For my purposes, I want to go from % co2 to the factor by which that changes the radiation into space and back to earth. One approach I saw just treated it as a blanket which radiates via T^4 on top with the reduced temperature at high altitudes, and below with the full temperature. Another approach just treated it as some kind of partial insulator.
The fool hath said in his heart, There is a God. They are corrupt, they have done abominable works, there is none that doeth good.
Psalm 14, KJV revised edition