The Biosphere II project was abandoned when the green house gases became too high and forced those inside to get out. In the future human colonies will have to worry about such things on other planets as well. Enclosed human habitats will need to replenish the oxygen and be sure to use the CO2 for something else or separate it out again.

If CO2 levels rise too high too fast then some of the gas may need to be abandoned or discharged to re-acclimate the suitable artificial environment to the proper levels to sustain human and life. Now then the last thing you want to do is discharge anything, what you really want is to separate out the CO2 so you can keep the Oxygen for human life but leave the proper amount for the plants.

If this problem happened in Biosphere II can it be happening on Earth too? And if so what can we do? Can we send some pollution out into outer space thru the ozone holes at the poles? What are we going to do as a species if we run out of fresh air to breath? Some folks believe in climate change and others in global warming, but if this is happening and it is rapidly increasing it really does not matter what is causing it, as we need to do something to get rid of the CO2 build ups if human civilizations are to survive. Consider all this in 2006.