It's more of a textbook die-off scenario, that - unfortunately for us - is going to be the biggest in history.

Maybe if we're lucky we'll be hit by an asteroid, and we'll be able to blame that instead.

The real problem is that evolution has bred humans to be smart enough to deal with small-scale survivability issues - like 'Whose brain do I eat today?' - but not smart enough to think globally. The predictive horizon of the average human ends at his or her front door. If they're lucky. Thinking far beyond that is too much of a stretch.

And among the humans who are - possibly - smart enough, there's a persistent brain-eating predator class which has no interest in anything except their own immediate pleasure.

We still cannibalise each other economically. And now we've cannibalised most of the planet too.