As soon as you acknowledge that we're changing the planet on this scale, that it has very potentially massive repercussions and very damaging repercussions, then the next question is okay, what are we going to do about it?

Of the many species that have existed on earth - estimates run as high as fifty billion - more than ninety-nine per cent have disappeared. In the light of this, it is sometimes joked that all of life today amounts to little more than a rounding error.

Humans will eventually become extinct. People treat that as a radical thing to say. But the fossil record shows us that everything eventually becomes extinct.

You're an animal that needs to move across the landscape, you can't anymore, and that's another way we're just changing the surface of the Earth in very dramatic ways.

Neanderthals were pretty smart, and if we actively killed them off, then probably we did so in the same way that humans kill each other.

Even very smart people can try to shoehorn new information that just doesn't fit into an existing paradigm.For a long time the story that we've been telling ourselves is that humans are just another animal. We evolved from other animals and our place in the universe isn't particularly special. What I'm trying to convey in my book [The Sixth Extinction] is that we are unusual.

We're talking really huge global-scale change, and I did not feel that I had the prescription for that kind of action, so I'm going to leave it to the reader.