“A temperature rise of more than two degrees C risks altering the Earth system irreversibly.”

“Humans on Earth behave in some ways like a pathogenic micro-organism, or like the cells of a tumor.”

— James Lovelock, Gaia: The Practical Science of Planetary Medicine (2000)

“I’d look for life on Mars in the composition of its atmosphere, not by crawling around looking for …”

— James Lovelock, NASA Mars life-detection research, early 1960s

“Whenever philosophers and scientists have tried to explain how life evolved, they have made the same …”

— James Lovelock, The Ages of Gaia (1988)

“The Gaia hypothesis is for those who like to walk or simply stand and stare, to wonder about the …”

— James Lovelock, Gaia: A New Look at Life on Earth (1979)

“We have given Gaia a fever and soon her condition will worsen to a state like a coma. She has been …”

— James Lovelock, The Revenge of Gaia (2006); originally from an op-ed in The Independent, 2006

“Gaia is a very simple idea: that the Earth works as a single, complex, self-regulating system.”

— James Lovelock, The Ages of Gaia (1988)