[thaumasiotes]

> Because carbon dioxide and dinitrogen are very volatile they must be taken from atmosphere.

I don't follow the logic. These two ideas are definitely compatible - oxygen is very volatile, and it's present in significant quantities in the atmosphere, and therefore can be (and is) taken from the atmosphere.

But they seem to me to be in tension rather than supporting each other. Oxygen is present in the atmosphere, but _because_ it is very volatile, it's constantly reacting with stuff on the ground, which is a process that tends to eliminate it from the atmosphere. What's the reasoning that suggests that the volatility of carbon dioxide means it has to be taken from the atmosphere?