[merpnderp]

Given how much crop land would be ruined, it is likely that global starvation would end most of humanity and not much of civilization would survive. Sure there would be people wondering around a hundred years later, but they might not know how to read, write, speak real languages, or reason abstractly. 99% of humans starving would make for some crazy times.

[monocasa]

Yep, see the bronze age collapse for an example of this.

Reading and writing lost. People living in cities that had flourished for a thousand years just a couple centuries before, but the current inhabitants didn't know the name of.