“Clearly, gas causes warming”
You simply do not understand how the Earth warms and cools.
CO2 and water vapor prevent the outward radiation of heat from the earth in the same way class traps heat in a green house. Therefore the CO2 and moisture in the air are green house gasses.
That is the big but plausible lie
I think I have a grasp on the concept, at least as good as you do. I know enough to know that water vapor is by far the strongest greenhouse gas in our atmosphere, and that the amount of warming caused by increased CO2 is miniscule in comparison.
Sun output variability has more influence on "global warming" than anthropogenic CO2.
I also know that without any atmosphere at all, Earth would not be the temperature it is today, even with its molten core.