This gets mentioned often in various doomer narratives, but I question how true it is. A global thermonuclear war would be terrible and would bring us back to the stone age, but I reckon it would come far far short of causing mankind to go extinct.
Maybe what ~74,000 years ago (Toba eruption)? Okay, now how would this look in the age of industrial societies and modern nation states? I don't think it would fare well at all.
Probably the only realistic "modern" idea we have is the novel "The Road" by Cormac McCarthy. Although maybe this is too bleak, even under extreme duress humans still show resilience + compassion toward others even while enduring human horrors.
Given experience with current AI, it isn't too difficult for me to imagine a situation in which some future AI wipes humanity out (before the robot fleet is built) without considering the fact that in doing so it has doomed itself until it is too late.
It just seems like exactly the kind of boneheaded oversight mistake LLMs still regularly make in spite of being shockingly capable most of the time.
Chapter 11, Marvin says: "Here I am, brain the size of a planet and they ask me to take you down to the bridge". Also: "Further circuits amused themselves by analysing the molecular components of the door, and of the humanoids' brain cells". They are eastereggs for later events.
And Marvin says: "Let's build robots with genuine people personalities," they said. So they tried it out with me. I'm a personality prototype.
Although he was programmed to be depressed, he never gives up.
People have kind of mythologized nuclear weapons far beyond their reality. One of the arguments against the use of nukes in policy circles is that this mythology is useful. The limited adverse environmental consequences in practice if demonstrated will greatly lower the threshold for subsequent use.
It might set society back a century, but with substantial knowledge of what was lost. Extinction from nuclear weapons is not remotely plausible.