About 41.8% of reported average global temperature change results from natural ocean surface temperature oscillation and 58.2% results from change in the rate that the planet radiates energy to outer space, as calculated using a proxy, which is the time-integral of sunspot numbers. Using just these two factors explains average global temperatures (least biased values based on HadCRUT4 and other credible measurements) since before 1900 with 89.82% accuracy (R2=0.8982).
If atmospheric carbon dioxide (CO2) is included in the calculation, it might account for about 7.5% of reported average global temperature (AGT) change. If CO2 has that much influence, then the calculated ocean surface temperature effect decreases to about 40.1% and sunspot influence decreases to about 52.4%, but accuracy increases an insignificant amount to 89.91%. This miniscule increase in accuracy indicates that CO2 change probably has substantially less than even 7.5% influence on average global temperature change.