posted 7 years ago
My guess would be a relatively sudden climate shift, such as an ice age, where perhaps knowledge how such a thing might be survived hadn't been developed, or hadn't been passed around sufficiently; mass-starvation due to a climate shift and inadequate adaptation seems plausible to me.
Another possibility might be a similar circumstance, but one caused by the byproducts of increased volcanic activity, where one or more large volcanic eruptions block out the sun for a season or more.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein