[Retric]

People aren’t going to destroy all life on earth via climate change because humans are going to be dead in conditions that many life forms would happily survive in. Having said that, evolution operates on geologic timescales 100 years isn’t nearly enough time for most species to adapt to significantly different conditions. Florida alligators might happily expand their range further north in response to climate change, but that’s different.

As to the larger point, the sun was ~30% dimmer 4.5 billion years ago and will get about 67% brighter over the next 4.7 billion years. While we would be dead long before we could free up all the worlds trapped carbon, in such a hypothetical situation the world isn’t simply returning to an earlier state.

[imtringued]

Some people argue that co2 levels were higher in the past. Yeah but the sun was a few degrees cooler. You simply needed more co2 to reach similar temperatures.