The observation that CO2 is a ghg (greenhouse gas) is a shallow penetration of the science. Delve deeper into the science and discover that CO2 does not now, has never had and will never have a significant effect on climate. Here is why.
1) Essentially all absorbed outgoing longwave radiation (OLR) energy is thermalized (i.e. shared with surrounding molecules).
2) Thermalized energy carries no identity of the molecule that absorbed it.
3) Emission from a gas is quantized and depends on the energy of individual molecules.
4) This energy is determined probabilistically according to the Maxwell-Boltzmann distribution.
5) The Maxwell-Boltzmann distribution favors lower energy (longer wavelength) photons.
6) Water vapor exhibits many (170+) of these longer wavelength bands.
7) The Maxwell-Boltzmann energy distribution in atmospheric gas molecules effectively shifts the OLR energy absorbed by CO2 molecules to the lower energy absorb/emit bands of water vapor. The ‘notches’ in top-of-atmosphere measurements over temperate zones demonstrate the validity of this assessment.
8) As altitude increases (to about 10 km) the temperature declines, magnifying the effect.
The only thing countering the temperature decline that would otherwise be occurring is the increasing trend in water vapor. (‘Otherwise’ results from declining net effect of ocean cycles since 2005 and declining solar activity which has been declining since 2014 and dropped below ‘break even’ in early 2016). Average global atmospheric water vapor has been measured and reported by NASA/RSS since 1988 and shows an uptrend of 1.5% per decade. WV has increased about 8% since the more rapid increase began in about 1960. This is more than 2.5 times the expected rate from temperature increase alone (i.e. feedback).