Quote:
Can you reference a study that has determined CO2 is able to be the primary cause of the current warming, without relying on historical data??



The references should be easy to find. One can theoretically calculate the warming from CO_2. Calculating the absorbtion spectrum of CO_2 is basic quantum mechanics, any physics student should be able to do this using some computational resources.

Increasing the CO_2 from the pre industrial 0.028% to the current 0.038% has a significant effect that is consistent with the observed warming. Numerous (many thousands) of peer reviewed articles show this. If climate on large time scales is less sensitive to CO_2, then that can only be because of feedback effects that you don't see on small time scales.

So, it's basicaly as certain as the fact that adding heat to a system will make it hotter.