Originally Posted by
RobertP
Extinction of the human race does not imply “the end of the world”. planet earth or whatever you call it, still has a few billion years left before our star expires and it would probably survive extremely well without the human species.
It's actually "only" just a few hundred million years until the Sun will have changed enough to have massive impact on our planet, including all life forms (like us, in case we would still be here, which I doubt). The atmosphere will change significantly due to increasing radiation and luminosity of our star. The balance within the so-called habitable zone that allows carbon-based life forms to exist is surprisingly delicate and does not allow significant variation in most parameters.
In about 500-700 million years, C3 photosynthesis will likely stop to work, because there won't be enough CO2 in the atmosphere, despite all climate change and rising CO2 levels we currently have, CO2 will drop significantly with increasing solar radiation over the next few hundred million years until there is not enough left to keep photosynthesis running. At some point, most plant life will be dead, which will in turn lead to a massive change in available oxygen. And then it's probably game over for any higher life form.
Still plenty of time though for recovery from the human mishap and maybe even a new try to establish intelligent life through further evolution.