But warnings (e.g. not apocalyptic but damaging or having any effects) have come true, by and large; people warned about the effects of pollution / co2 emissions / global warming over 150 years ago [0], to name a popular example.

I don't think there are many truly human created apocalyptic events out there besides global thermonuclear war, and I don't think the worst-case AI superintelligent killer robot scenario would be apocalyptic. Unless it somehow triggers global thermonuclear war, but then it becomes a chicken-or-egg question (and it'll probably be humans pushing the proverbial button, as nukes are '60s tech and (hopefully) airgapped etc).

[0] https://en.wikipedia.org/wiki/Svante_Arrhenius