CO2 change, and therefore human activity, does not cause global warming. The reason is that terrestrial radiation absorbed by CO2 is immediately thermalized, i.e. the energy absorbed by CO2 is handed over (in a process similar to thermal conduction) to other atmospheric molecules which outnumber CO2 molecules 2500 to 1. CO2 can only absorb terrestrial EMR that has wave length 14-16 microns out of the significant range 5-50 microns of terrestrial radiation. The absorption/thermalization quickly depletes the 14-16 micron radiation flux coming from the surface.
But this leaves the question of what actually does drive average global temperature change.
After some research to find out what causes climate change. . .
Two primary drivers of average global temperature have been identified. A simple equation, using only them, very accurately explains the reported up and down measurements since before 1900. The coefficient of determination, R2>0.9 (correlation coefficient = 0.95). The equation provides credible estimates back to the low temperatures of the Little Ice Age (1610). The current trend is down.
R2 = 0.9049 considering only sunspots and ocean cycles.
R2 = 0.9061 considering sunspots, ocean cycles and CO2 change.
The tiny difference in R2, whether considering CO2 or not, corroborates that CO2 change has no significant effect on climate.
The coefficients of determination are a measure of how accurately the calculated average global temperatures compare with measured. R2 > 0.9 is very accurate.
The calculations use data since before 1900 which are official, accepted as valid and are publicly available.
Solar cycle duration or magnitude, considered separately, fail to correlate but their combination, expressed as the time-integral of solar cycle anomalies, gives excellent correlation. A solar cycle anomaly is the difference between the sunspot number for a year and an average sunspot number for many years.
Everything not explicitly considered (such as the 0.09 K s.d. random uncertainty in reported annual measured temperature anomalies, aerosols, CO2, other non-condensing ghg, volcanoes, ice change, etc.) must find room in the unexplained 9.51%.
Search AGW unveiled for the method, equation, data sources, history (hind cast to 1610) and predictions (to 2037).