Those humans are also producing CO2 so it will have some self-sustainability. The 5% CO2 of human breath is a lot more than the ~0.04% in the atmosphere. I ha

Those humans are also producing CO2 so it will have some self-sustainability. The 5% CO2 of human breath is a lot more than the ~0.04% in the atmosphere. I have no idea how to calculate the steady state or what the losses would be.