Maybe I'm missing something, or maybe this is a matter of definitions, but this feels alarmist to me. I have to think that there are many believable scenarios (e.g., in Ukraine) where "only" one to ten nuclear detonations would be employed. That seems like a "small" nuclear war and while it would undoubtably have many negative repercussions, it would not end world civilization.
Why do you think it would not escalate? Do you have a crystal ball?
I don't know anything about anything, but there have been many regional conflicts over the last 100 years that have remained regional. I don't see how the technology used to fight those regional conflicts changes anything.
Perhaps the social connotations of those technologies is significant enough that using some rather than others is "triggering" enough that non-combatants can't help but get involved. <shrug>
I agree that these exist.
I do not believe that they are as significant as the general public believes. After all, there have been more than 500 nuclear weapons detonated world-wide in the open atmosphere. [0]
If these non-local effects are very large, why would we take Russia's threats of using nuclear weapons against a neighbor as credible?
[0]: https://www.armscontrol.org/factsheets/nucleartesttally
Even if the chance is tiny, you don't want to risk a nuclear conflict because there is no going back to the world that we live in after that. I am always dumbfounded at the lack of awareness that having a direct conflict with a nuclear power increases the risk of nuclear war.
And what happens next? It's not like there is some kind of enforced rule that WMDs aren't to be used unless the other side doesn't use them. Strategic WMDs deter against a total loss to a foreign power, by any means, not just other WMDs, don't they?
Based on what exactly? Like, how do you imagine a successor would appear while the US devastates Russian army and how would they "have less face to lose" when their military is devastated?
It is unlikely that anyone will be replacing Putin in the heat of battle, and its hard to imagine a "less face to loose" situation - it's not like it's for one person to decide and Russian politics doesn't work that way either - there is no tradition to reset politics every few years with a new talking head. No idea how mr "Less face to lose" would be able to do something like that without starting a civil war.
What matters is what happens next. Russia razing Europe and the US in nuclear fire if they feel they are cornered have nothing to lose. Good luck with pushing things this far.
After all, the MAD strategy did keep us safe during the cold war while giving up their nukes did bring Ukraine an invasion.
Like General Milley secretly telling the Chinese government that Trump wouldn't be able to use nukes against them? He hasn't been tried for treason, so some people clearly don't think it's that important.