Last night I watched a video on why the middle of the sixth century AD was so socially and historically cataclysmic. Scientists claim the Krakatoa volcano had a major blow which dimmed the sun for awhile and resulted in (1) droughts which drove the Mongolian steppe warriors to invade the Roman Empire and also likely destroyed the Mayan culture; (2) cooler weather led to proliferation of a flea which carried plague to the Roman and Celtic civilizations; (3) another effect of the drought was to destroy the Yemen hegemony and drove ambitious people to Medina including Mohammed’s family. In other words, a whole lot of unforeseen consequences can happen.
In other words, a whole lot of unforeseen consequences can happen.
I read how US was impacted in 1816...
https://en.wikipedia.org/wiki/Year_Without_a_Summer