Part of the problem of getting +/- 8C of different global temperature is the speed of it. https://xkcd.com/1732/ shows a timeline that goes back to 20000 AC, where global average temperature was like 5ºC less. There has been changes, but also adaptation. Now in less than 200 years we increased 2ºC, and the speed of change has increased, it was around 10 years ago when we reached 1ºC over preindustrial times, and now we are at 1.5ºC.
And without adaptation you get mass extinction. And the human system may be pretty fragile against the disappearance or deep change of key components of the global system.
And without adaptation you get mass extinction. And the human system may be pretty fragile against the disappearance or deep change of key components of the global system.