I grew up listening to fundie christian parents babble at length how we were living in end times. And mocking them mercilessly (at first among my fiends, later to their faces) as often as possible.
Now look at us - on the brink of non-existence politically, environmentally, and civilizationally. Not sure that last one is a word.
If they were right I’m gonna have some 'splainin to do.
Dammit.
There is nothing in the IPCC reports that even come close to civilization-ending predictions from climate change.
First IPCC is a political process with high input from climate terrorists.
You are right that the requirement for ending civilization requires over 95% population decline. Civilization existed in bronze age. Global warming is unlikely to be a near extinction event, as technology to survive, especially for a small population, should keep up.
What should be clear though is mass loss of prosperity and life is a cycle to lose more prosperity.