Comment by mikeash

When has the human race come close to extinction by our own hands? The only near-extinction I'm aware of is the theorized population bottleneck caused by the Toba eruption, whose existence seems to be disputed and which in any case wasn't caused by our own hands.

If you're referring to global thermonuclear war, there was (and still is) the constant threat of destroying civilization, but never any chance of causing the extinction of the species.