As the plane sped down the run-way and into the smog-filled air above Heathrow, I knew that this was not the place to be reading James Lovelock's new book. Each time I turned a page, I thought with shame of the vast quantities of carbon dioxide that were pouring out of the jet's engines. That I was on a lecture tour of Sweden to talk about global warming seemed irrelevant; I, too, was doing irreparable damage to the environment. In the process, as Lovelock explains, I was also taking part in a war of attrition, waged by humanity against the systems that have kept this planet friendly to life for more than two billion years.
Given Lovelock's scientific and environmental pedigree, this book deserves to be taken seriously. As the originator of the Gaia theory - the idea that chemical, physical and biological systems combine in a complex web of self-regulation that keeps the planet habitable, almost as if it were itself an organism - Lovelock has revolutionised the study of Earth science. You can't grasp how the oceans work just by examining plankton under a microscope, just as you won't gain an insight into the Amazonian rainforest by studying a single tree. The web is all: organisms can function only as part of wider ecosystems, in a planet-wide matrix that they unconsciously help to control. Amazonian trees, for example, don't just sit there waiting for the rain; they create their own weather by recycling water over vast distances. Such complex beauty, from powerful tropical thunderclouds to the smallest soil microbe, is Gaia in action.
Then we came along. With the proliferation of Homo sapiens, the system has become unbalanced. Human beings discovered the tools to tame and dominate nature, from fire to agriculture, and with the coming of fossil energy our numbers exploded. Humans now appropriate more than 40 per cent of the entire photosynthetic productivity of the planet, leaving the rest of nature to scrape along at the margins, in places that are too hot, too cold, too high or too low to be useful to us. The effects have been catastrophic. Today, atmospheric greenhouse-gas levels are far higher than at any other time in the past 30 million years. As Lovelock warns, Gaia is not forgiving of species that alter their environment to the detriment of their offspring and other life. We are entering a new hot age, one that human civilisation will almost certainly not survive.
We are well into the emergency, although most humans don't yet seem to know it. The prevailing economic and political wisdom suggests that things can go on as normal with only minor adjustments - a windfarm here, a little carbon trading there. Lovelock argues that such tinkerings will hardly even begin to assuage Gaia's wrath. Instead, we need to focus on protecting the sum of useful human knowledge from being lost in the coming chaos, just as monks in the Dark Ages guarded and passed down the insights of ancient Rome and Greece until civilisation and enlightenment returned.
It's a scary message, but Lovelock has not given up yet: he spends dozens of pages exploring the energy options that might allow us to reduce the damage we are doing. Electrical energy is especially crucial. Deprive a city such as London of electricity, and within a couple of weeks it would look like New Orleans after Katrina - little more than a giant refugee camp. This explains Lovelock's controversial support for nuclear power: nothing else, he argues, can guarantee secure and relatively safe electricity for decades to come.
Although Lovelock describes himself as a "green", environmentalists will not find this book an easy read. He slaughters their sacred cows with a kind of ghoulish glee, extolling the virtues of the notorious pesticide DDT one minute and dismissing environmentally driven concerns about radiation and cancer the next. Alternative medicine does nothing more than "titil-late the hypochondria" of the chattering classes. He reserves particular scorn for so-called "urban environmentalists" who tut-tut about perfectly harmless synthetic chemicals while tucking in to their organic chipolatas, especially if they promote the rural windfarms that he so despises. Many readers will find his rabid denunciation of wind power less than persuasive, and his offer to keep all the UK's high-level radioactive waste in his back garden (he would use the waste heat to keep the house warm) is startling. Perhaps his book should carry a special label: "Warning - for those with open minds only. Do not read if you cannot be persuaded."
Yet this contradiction somehow sums up the book: it is both entertaining and utterly terrifying, both thoughtful and constantly provocative. Above all, it is crammed with the common sense of someone who has combined penetrating intellect with a lifetime of experience. Lovelock is not quite writing our civilisation's epitaph, but he is ringing a warning bell, and its echoes should reverberate throughout the world.
Mark Lynas is the author of High Tide: news from a warming world (HarperCollins)