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

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.

One pound of uranium is worth about 3 million pounds worth of coal or oil.

I have a feeling that climate change may be an issue as severe as a war. It may be necessary to put democracy on hold for a while.

Esso has been the main one in America spreading the disinformation that there is no global warming problem.

We are in a fool's climate, accidentally kept cool by smoke, and before this century is over billions of us will die and the few breeding pairs of people that survive will be in the Arctic where the climate remains tolerable.

By 2040, the Sahara will be moving into Europe and Berlin will be as hot as Baghdad. Atlanta will end up a kudzu jungle. Phoenix will become uninhabitable, as will parts of Beijing (desert), Miami (rising seas) and London (floods). Food shortages will drive millions of people north, raising political tensions.