> The Earth has also been a lot warmer than it is now so I have trouble believing the doomsday scenarios of runaway climate change that'll turn the Earth into Venus just because the Earth has been here for 4-5 billion years, has been hotter than now and hasn't become Venus yet. We also seem to have a pretty poor history of predictions when it comes to climate change too.

This is disingenuous because humans have been around say 2M years, and those hot climate years were >5M years ago. (https://en.wikipedia.org/wiki/Geologic_temperature_record).

We don't need Earth to have Venus conditions for it to be a big problem for us.