> you still wouldn't get Venus. Venus's atmosphere is almost 100 times denser than earth, and it's nearly 100% CO2 That extremely high amount of CO2 in the atm

> you still wouldn't get Venus. Venus's atmosphere is almost 100 times denser than earth, and it's nearly 100% CO2 That extremely high amount of CO2 in the atmosphere of Venus is not the original cause but a consequence of runaway warming. At a few hundred degrees C, the carbon dioxide bound in rocks starts to sublimate into the atmosphere. For example, limestone would go CaCO3 -> CaO + CO2. 10% of all sedimentary rock is limestone so one can see how that leads to a Venus-like atmosphere. That said, I agree that a Venus scenario doesn't seem to be possible for Earth right now. In this paper published in Nature, even 3000 ppm of CO2 (i.e. all fossil fuels burned) was calculated not to trigger such a thing. It would require more like 30,000 ppm, which is not really breathable atmosphere anymore: http://www.nature.com/ngeo/journal/v6/n8/full/ngeo1892.html http://www.nature.com/ngeo/journal/v6/n8/full/ngeo1892.html Coverage in scientific american: https://www.scientificamerican.com/article/fact-or-fiction-runaway-greenhouse/ https://www.scientificamerican.com/article/fact-or-fiction-r...