If you start any large theory, such as quantum mechanics, plate tectonics, evolution, it takes about 40 years for mainstream science to come around. Gaia has been going for only 30 years or so.

You never know with politicians what they are really saying. And I don't say that in a negative way-they have an appalling job.

One thing that being a scientist has taught me is that you can never be certain about anything. You never know the truth. You can only approach it and hope to get a bit nearer to it each time. You iterate towards the truth. You don't know it.

It just so happens that the green religion is now taking over from the Christian religion. I don't think people have noticed that, but it's got all the sort of terms that religions use. The greens use guilt. That just shows how religious greens are. You can't win people round by saying they are guilty for putting (carbon dioxide) in the air.

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.

The oil companies regard nuclear power as their rival, who will reduce their profits, so they put out a lot of disinformation about nuclear power.

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.