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.

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?

[On the birther movement:] Here we are, quadrillions of bytes deep into the Information Age. And yet information, it seems, has never mattered less.

Some of these species that are now no longer with us were killed off by a fungal disease that was moved around the planet by people.

In a poll commissioned by Time and CNN, two-thirds of American parents said they think that their children are spoiled.

The Earth is big. There are huge natural forces that have worked over geological time. But it turns out, when you look carefully at the geological time, you can't find anything like us.

No matter what Donald Trump says, it's clear that global warming is rapidly changing conditions on our planet.