[saalweachter]

I agree that we as a species can probably survive nearly anything.

Derailing, I think it's also pretty reasonable to worry about events that will only wipe out 99.9% of humanity. Statistically, I'm probably dead in such a case. Probably everyone I know is dead. My back-of-the-envelope calculation says that I probably can't expect more than a fifth cousin to survive if 99.9% of people are dead. I don't even know any of my fifth cousins.