The entire range of living matter on Earth from whales to viruses and from oaks to algae could be regarded as constituting a single living entity capable of maintaining the Earth's atmosphere to suit its overall needs and endowed with faculties and powers far beyond those of its constituent parts.

We are the intelligent elite among animal life on earth and whatever our mistakes, [Earth] needs us. This may seem an odd statement after all that I have said about the way 20th century humans became almost a planetary disease organism. But it has taken [Earth] 2.5 billion years to evolve an animal that can think and communicate its thoughts. If we become extinct she has little chance of evolving another.

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

China will soon emit more greenhouse gases than America, but its regime knows if it caps aspirations there will be a revolution.

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.

The big threat to the planet is people: there are too many, doing too well economically and burning too much oil.

This programme to stop nuclear by 2020 is just crazy. If there were a nuclear war, and humanity were wiped out, the Earth would breathe a sigh of relief.