The Revenge of Gaia, by James Lovelock

James Lovelock will go down in history as the scientist who changed our view of the Earth from a barren rock covered with a thin coating of life to a self-organising system that in many ways resembles a single organism. Following a conversation with the novelist William Golding, Lovelock named this self-regulating system after the Greek earth goddess Gaia. Viewed with suspicion by Darwinian fundamentalists, Gaia theory is now widely accepted and used in scientific disciplines. Its implication is that humanity is part of a much larger system that it cannot control, still less master. The Earth's self-regulating processes impose limits on human ambitions, and if humanity acts to destabilise the system, the Earth will readjust in ways that show no regard for human welfare.

In The Revenge of Gaia - the most important book ever to be published on the environmental crisis - Lovelock applies Gaia theory to climate change. Using the latest scientific findings, he concludes that an abrupt and radical climatic shift is unavoidable. Global heating - as he prefers to describe it - is set to take its course: "We are the cause of it, and nothing so severe has happened since the start of the Eocene, 55 million years ago, when the change was larger than that between the ice age and the 19th century and lasted for 200,000 years".

The shift already visible in the melting Antarctic means that rising sea levels will threaten billions. Within the present century, many coastal cities could be inundated and much of the world's arable land flooded. Destabilised by human activity, the Earth is readjusting and becoming less habitable by humans. Gaia is exacting her revenge on human hubris. There will be some who say that Lovelock's talk of Gaia exemplifies the sympathetic fallacy of reading human feelings into the natural world, but his point is that if we try to override the Earth's self-stabilising mechanisms we court disaster. Gaia's revenge is a metaphor for cause and effect operating on a planetary scale.

Lovelock's claim that climate change is irreversible has horrified many Greens, who see it as a counsel of despair. Here the movement is in denial. If the evidence supports Lovelock's claim - and there is a growing scientific consensus that it does - many policies advocated by the Green movement are pointless, or positively harmful. Green hostility to nuclear power is an example.

Lovelock's pro-nuclear stance is not new; it was clear in his first book, Gaia (1979). Here, Lovelock restates his view that it is folly to reject a source of energy that is highly efficient and less harmful to the environment than existing alternatives. He will not persuade those whose opposition is irrational, but anyone with a reasonably open mind will conclude that the nuclear option can't simply be dismissed. I have supported Lovelock's environmental defence of nuclear power since 1992, when I endorsed it in my book Beyond the New Right.

What is new is Lovelock's argument that high technology can be used to reduce humanity's impact on the planet. Conventional Greens promote the idea of sustainable development, and think the environmental crisis can be overcome by low-tech solutions such as organic farming and renewable energy. In contrast, Lovelock believes sustainable development is no longer possible. Rightly, he maintains we need a hi-tech strategy that enables humanity to stage a sustainable retreat from its current over-extended position in the biosphere.

There is no technical fix for the human condition; but Greens are deluding themselves if they think the environment can be saved by changes in the economic system. Using hi-tech methods, we might just be able to feed the world's growing population during the period of upheaval that is now inevitable. There is no prospect of this with traditional farming, and we would be better off if we abandoned agriculture altogether and produced foods synthetically. The Green utopia of a vast human population subsisting on a mix of wind farms and organic food would mean gutting the planet of much of its remaining biodiversity.

Fortunately, it is not remotely possible. As Lovelock puts it, "An ultra-high-tech low-energy civilisation may well be possible, but it would be wholly different from the present-day vision of a low-energy world of sustainable development and renewable energy where the multitude tries to survive on food from organic small-holders farming a protesting Earth."

Lovelock writes that the root of the environmental problem is a lack of constraint on human numbers, and I am sure he is right. With a population of a billion or fewer, the planet would be healthy whatever humans did to it. As it is, unchecked human expansion has disrupted the mechanisms that keep it stable. The question is not how humanity can retain its planetary dominance, which was always an illusion. It is whether humanity can use science and technology to mount a sustainable retreat. If not, Lovelock warns, we face "a global decline into a chaotic world ruled by brutal warlords on a devastated Earth".

John Gray is professor of European thought at the LSE and the author of 'Straw Dogs' (Granta)