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.

Our future is like that of the passengers on a small pleasure boat sailing quietly above the Niagara Falls, not knowing that the engines are about to fail.

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.

I think that we reject the evidence that our world is changing because we are still, as that wonderfully wise biologist E. O. Wilson reminded us, tribal carnivores. We are programmed by our inheritance to see other living things as mainly something to eat, and we care more about our national tribe than anything else. We will even give our lives for it and are quite ready to kill other humans in the cruellest of ways for the good of our tribe. We still find alien the concept that we and the rest of life, from bacteria to whales, are parts of the much larger and diverse entity, the living Earth.

The Earth's population will be culled from today's 6.6 billion to as few as 500 million, with most of the survivors living in the far latitudes - Canada, Iceland, Scandinavia, the Arctic Basin.

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.

What we have lived through, the 20th century, has been like a great party. Adults now have had the best time humanity has ever had. Now the party is over and the Earth is reckoning up.