> whatever the reason

Both Iceland and Italy have had multiple serious eruptions that could have wrapped around 2 or more winters in Europe and N. Africa, starving almost everybody.

I once read that our mitochondria indicates the human population was down to 5,000 at one time.

Here's one article mentioning the Toba explosion 70,000 years ago and blocking the sun for 6 years. There's still a Lake Toba:

https://www.npr.org/sections/krulwich/2012/10/22/163397584/h...