Is there a minimum greenhouse factor? I'm currently seeing if I can stay alive in a default conventional start with the sun warming 1% a year. According to the formula on the environment tab if I add anti-greenhouse gas the green house factor will go negative before I hit the max atmosphere pressure. It would happen at about 2.22 total pressure.
And looking at the numbers now it looks like anti-greenhouse gas makes this a joke, if the minimum greenhouse factor is 0.01 then the earth would have to break 31,715 kelvin to become to warm for humans. I think the game will be long over before that happens.