And if, Jelbring's proposed thickness of the
atmosphere involved, is greater than, the gas won't even be in contact with the upper surface
anyway, it will be strictly confined to a height less than because that is the height where the absolute temperature, concentration, and pressure of the lapsed gas
reaches zero.
Anyway, if the deep ocean volcano CO2
reaches the
atmosphere, that would increase the CO2 and δ13C in the
atmosphere, while the largest changes are in the NH spring / summer with decreasing CO2 levels and increasing δ13C.