"We have since defined Gaia as a complex entity involving the Earth's biosphere, atmosphere, oceans, and soil; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet."

“Bacteria... have been here for three and a half billion years, and without them we have no chance whatsoever of survival. Humans are something very recent, like the froth on top of a glass of beer.”

“If there were a billion people living on the planet, we could do whatever we please. But there are nearly seven billion. At this scale, life as we know it today is not sustainable.”

“Challenging the conventional wisdom is the way to make waves in science.”

“In the current fashionable denigration of technology, it is easy to forget that nuclear fission is a natural process. If something as intricate as life can assemble by accident, we need not marvel at the fission reactor, a relatively simple contraption, doing likewise.”

“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 a war. It may be necessary to put democracy on hold for a while.”

“If you were an artist or novelist, or a poet or somebody like that, nobody would think it odd if you worked in your own home. In science there's none of this at all. I'm almost the only independent scientist in Britain. Everybody else works in large institutions, universities, or industrial labs. Why should one expect scientists to work that way?”