Lets remember that sustainable and self sufficient are two different terms.
A practice is sustainable if it can be continued indefinitely without detriment to the environment or whatever system it is part of.
Original link is dead. You can download it here, but need a scribd membership: https://www.scribd.com/doc/2100251/Jared-Diamond-The-Worst-Mistake-in-the-History-of-the-Human-Race
And when my army is complete, I will rule the world! But, for now, I'm going to be happy with this tiny ad:
Ernie and Erica Wisner's Rocket Mass Heater Everything Combohttps://permies.com/t/40993/Ernie-Erica-Wisner-Rocket-Mass