All the modelling we do shows that the climate is poised on the jump up to a new hot state. It is accelerating so fast that you could say that we are already in it.

Life does more than adapt to the Earth. It changes the Earth to its own purposes.

If we gave up eating beef we would have roughly 20 to 30 times more land for food than we have now.

There is no clear distinction anywhere on the Earth's surface between living and nonliving matter. There is merely a hierarchy of intensity going from the 'material' environment of the rocks and the atmosphere to the living cells.

What we have lived through, the 20th century, has been like a great party. Adults now have had the best time humanity has ever had. Now the party is over and the Earth is reckoning up.

We'd never have got a chance to go outside and look at the earth if it hadn't been for space exploration and NASA.

If it hadn't been for the Cold War, neither Russia nor America would have been sending people into space.