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.

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

People sometimes say we need to be really almost on a wartime footing if you want to change. Our whole economy is based on burning fossil fuels, which is taking CO2 out of the ground and putting it up into the air.

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.

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

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.

Increasingly developing countries are asking for aid to help deal with the consequences of climate change, which we don't want to give.