Slightly off topic...
Since the quantity of atmospheric CO2 is increasing, I have wondered what gas or gases - if any - are decreasing?
Or, is the total mass of the atmosphere increasing, which means that atmospheric pressure is now fractionally higher than 14.7 psi?
I think it might be on topic.
Here’s an interesting article about atmospheric escape. There’s Jean’s escape which is how helium and hydrogen slough off on a normal day, there’s polar wind, that sloughs off hydrogen and helium, and there’s hydrodynamic or planetary wind escape, regulated by the equatorial stratosphere, with hydrogen capable of dragging oxygen, argon, lighter isotopes and carbon dioxide off with it under certain temperature conditions. UV decomposition of carbon monoxide can accelerate the atoms to escape velocity.
So if the lower atmosphere is expanding, which would mean increased atmospheric pressure at sea level, what increase would drive upward pressure on the exosphere? Would hydrodynamic escape increase proportionately? Would that be a self-limiting ‘valve’? And how far can the exosphere expand, to what temperature, wihout being fried by the Sun? How thin can the exosphere get without being swept away by escape mechanisms or ionic storms? Is it even worth worrying about if a bleak atmospheric future is 2 billion years from now?
https://geosci.uchicago.edu/~kite/doc/Catling2009.pdf