>Our largest existential enemy right now is unsustainability. When has 'unsustainabilty' ever caused the destruction of a large portion of a human population?

>Our largest existential enemy right now is unsustainability. When has 'unsustainabilty' ever caused the destruction of a large portion of a human population? Seriously. Can you think of any? The two existential threats -- the two things that can, have, and will -- wipe out millions are War and Disease. Everything else -- asteroids, climate change, sustainability -- are speculative. But, evidence-based analysis clearly points to War and Disease.