Though it might be nice to imagine there once was a time when man lived in harmony with nature, it’s not clear that he ever really did.

There's this idea of shifting baselines. It was coined by a guy named Jeremy Jackson. It's the idea that every generation takes what it sees, and says, "Okay, well, that's the norm."

Somewhere in our DNA must lie the key mutation (or, more probably, mutations) that set us apart—the mutations that make us the sort of creature that could wipe out its nearest relative, then dig up its bones and reassemble its genome.

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. It depends what "eventually" means. But the idea that were going to be around for the rest of global history...I don't think there's any scientist who would suggest that is true. It could be millions of years from now. We may leave descendants that are humanlike.

We have all this Paleolithic art that suggests that our ancestors really venerated animals and that they depended on wild animals to survive - as opposed to domesticated animals that we depend on. Would it radically change things if we had more rhinos in our midst? I kind of suspect it would.

I traveled really to amazing places. I went to the Great Barrier Reef, I went to the Amazon, I went to the Andes, to try to bring people stories of sort of what's going on out in the world and bring this issue alive, in a way, and put it out there.

You've got to do everything, everything's got to be pointing in the same direction and you've got to really turn this whole economic engine from one that's based on fossil fuels to one that isn't.