If The Atmosphere Was 100% CO2 – The Earth Would Be Frozen

http://www.globalwarmingart.com/images/7/7c/Atmospheric_Transmission.png

Using the RRTM radiative transfer model (incorporated in NCAR’s climate and weather models) we can easily calculate that a 100% CO2 atmosphere would be extremely cold.

CO2 only absorbs a few narrow bands of LW radiation, meaning the vast majority would radiate directly out into space.