Quote Originally Posted by Cloud No.9
what makes our planet sustainable compared to mars and venus was the carbon cycle through rocks and rivers. messing it up would be as catastrophic as removing the moon.
Our planet isn't sustainable according to some theories. We may have only a few hundred million years before the earth is as baren and uninhabitable as Mars, or the other planets according to some. And believe it or not, it's supposedly because the overall quantity of CO2 in the atmosphere is expected to fall in the long run, until eventually, there won't be enough to sustain the plant life on earth and everything will die out.