What this means in practice is that we enter a minefield where we start to lose major ecosystems as temperatures continue to rise.
This makes it incredibly important to do everything we can to limit the amount of additional warming we see; each 1/10 of a degree adds to the risk.
Sadly, this will probably not make humans extinct. It’ll kill a lot of people and make life worse for even more, but some humans will survive. It’s a question of how much damage it does to the planet. I guess we could end up in a venus situation, but that’s probably unlikely. I’m not sure what’d have to happen to get to that point.
It would be interesting to see any detailed analyses on what is likely to persist in terms of human civilisation.
I’ve just consigned the whole idea to something more or less like the world wars where everyone afterward will wonder “what the fuck happened” but eventually accept their fate (humans are good at being slowly boiled unfortunately). To some extent there will be some memory of what was and why it was lost, but I suspect it’s unpredictable how that gets culturally encoded.