Layman struggles with Science

[Derek]

Richard111, please excuse this input, as I have not had time to fully digest what you have written,
(I have to fit heated grips to my motorcycle, so I'll be back later
- these supposedly warmer and wetter winters (according to UK Met office, are really freezing my fingers off....)
but in the meantime may I "throw in".

Here are the figures for Specific Heat in kJ/kg per degree C for the main constituents of the atmosphere

Oxygen ....... 0.9191
Nitrogen ..... 1.04
Argon ........ 0.523
Carbon Dioxide 0.85

If CO2 has a lower heat capacity than O2 and N2, will it not "react" first,
so at all times cooling the rest of the atmosphere it is in. ?

I am assuming that O2 and N2 mixed in the atmosphere will have the simple arithmetic heat capacity of
80% 1.04 + 20% 0.9191.
(roughly worked out as 1.015)
Is this correct. ?