There is little evidence that our individual intelligence has improved through recorded history.

A billion could live off the earth; 6 billion living as we do is far too many, and you run out of planet in no time.

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.

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

Our future is like that of the passengers on a small pleasure boat sailing quietly above the Niagara Falls, not knowing that the engines are about to fail.

If a power station were to be built down the road, I'd prefer a nuclear plant over an oil burner, and definitely over a coal burner. We simply have to lessen our consumption of fossil fuels.

We need a more authoritative world...What's the alternative to democracy? There isn't one. But even the best democracies agree that when a major war approaches, democracy must be put on hold for the time being. I have a feeling that climate change may be an issue as severe as war. It may be necessary to put democracy on hold for a while.