Life on Earth doesn't need us

We are like other species. We cannot put an end to Nature: we can only pose a threat to ourselves.

HUMANS ARE not the centre of life. Nor is any other single species. Life has existed at the planetary level for at least 3,000 million years. To me, the human move to take responsibility for the living Earth is laughable - the rhetoric of the powerless. The planet takes care of us, not we of it. Our self-inflated moral imperative to guide a wayward Earth, or heal our sick planet, is evidence of our immense capacity for self delusion. Rather, we need to protect ourselves from ourselves.

We are at the point of a very big crisis indeed in global biodiversity. Over 40 per cent of the land mass of the earth is now devoted to human agriculture. The cities are eating up the open spaces with their garbage and concrete. The forests are being taken over by agriculture. There is simply no way that this can be allowed to double in the next generation, which is the rate at which we are going.

Why should Homo sapiens, as the species is inaptly named, of all species, continue? There are anything up to 30 million species alive today. But 99.9 per cent plus of those that ever existed are extinct. It's not much use appealing, as many environmentalists do, for the saving of one particular species, one type of snail, when we're destroying their whole habitat.There is no scientific reason to think that we, even with space travel, are going to survive as a species for ever, certainly not by biting off the hand that feeds us, which is exactly what we are doing.

I came to this view through my collaboration with the independent scientist and inventor, James Lovelock. Our Gaia hypothesis, rejected by some as the fantasy of New Age crystal-swingers, demonstrates how biology is essential to the understanding of how Earth works.

Gaia is not, as many claim, a theory of the Earth as a single living organism. Yet the Earth, in the biological sense, has a body sustained by a complex physiology. Life is a global phenomenon, and the Earth has thus been alive for most of its history.

James Lovelock had already thought up the idea of a living Earth in the mid-Sixties, years before I met him, when he consulted for NASA. His major contribution was the electron capture device, a detector used to measure concentrations of certain reactive gases in the air, such as chlorofluorocarbons, which led directly to chemists understanding how the ozone layer was being destroyed. Borrowing a term from physiology, Lovelock pointed out that our planetary environment is "homeostatic". Just as our bodies, like those of all mammals, maintain a relatively stable internal temperature despite changing conditions, the Earth system keeps its temperature and atmospheric composition stable.

In engineering terms, Lovelock wrote, atmospheric temperature is regulated around given set points by negative feedback. His claims that life sets environmental temperature at an optimum were misunderstood, criticised or, more frequently, ignored. Lovelock increasingly thought of this planetary regulatory system as central to understanding life on Earth.

The term Gaia was suggested to Lovelock by William Golding, author of Lord of the Flies. In the early Seventies, they both lived in Bowerchalke, Wiltshire. Lovelock asked his neighbour if he could replace the cumbersome phrase "a cybernetic system with homeostatic tendencies as detected by chemical anomalies in the Earth's atmosphere" with a term meaning "Earth". "I need a four letter word," he said. Golding suggested "Gaia", the ancient Greek word for "Mother Earth". As such, Gaia provides an etymological root of many scientific terms, such as geology, geometry and Pangea.

The sum of planetary life, Gaia, is an emergent property of interaction among organisms, the spherical planet on which they reside, and an energy source, the sun. Furthermore, Gaia is an ancient phenomenon. Trillions of jostling, feeding, mating, exuding beings comprise her planetary system. Gaia is a tough bitch and is not at all threatened by humans. Planetary life has survived for billions of years before humanity was even the dream of a lively ape with a yearning for a hairless mate.

Politicians need a better understanding of global ecology. We need to be freed from our species-specific arrogance. No evidence exists that we are "chosen", the unique species for which all the others were made. Nor are we the most important one because we are so numerous, powerful and dangerous. Our tenacious illusion of special dispensation belies our true status as upright, mammalian weeds.

In popular culture, the confused idea of Gaia strikes mythological chords. Gaia resonates with our longing for significance in our short Earth-bound lives. We have, for centuries, personified nature. It is unfortunate that Gaia theory has been used for this vaguely spiritual agenda by mystics, and some of the more scientifically-illiterate environmentalists. But the planet is not human, nor does it belong to humans.

Now, a new scientific organisation, Gaia: the Society for Research and Education in Earth System Science, is bringing the lessons of global biology to a wider audience. Few of us will ever be able to get the unique perspective provided by seeing the Earth from space, but the Gaia society will help us share the planetary perspective of those who have. The urgency for developing the larger, interconnected perspective facilitated by Gaia has never been more pressing.

Despite our very recent appearance on the planet, humanity combines arrogance with increasing material demands, even as we become more numerous. Our toughness is a delusion. Have we the intelligence and discipline to vigilantly guard against our tendency to grow without limit? The planet will not permit our consumption of resources and production of wastes to continue to increase.

Runaway populations of bacteria, locusts, roaches, mice and even wild flowers always collapse. They choke on their own wastes as crowding and severe shortage ensue. Diseases follow, taking their cue from destructive behaviours and social disintegration. Even herbivores, if desperate, become vicious predators and cannibals. Cows will hunt rabbits or eat their calves, many mammals will vie for the meat of their runted litter mates. Population overgrowth leads to stress, and stress depresses population overgrowth - an example of a Gaian-regulated cycle.

We people eat just like our planet mates. We cannot put an end to nature; we can only pose a threat to ourselves. Runaway climate change and further intensification of industrial agriculture would do just that. But the notion that we can destroy all life, including the bacteria thriving in the water, tanks of nuclear power plants and deep-sea volcanic vents, is ludicrous. Many species, especially those in the four non-animal-kingdoms - plants, fungi, protoctists and bacteria - do not need humans to take care of them. The assertion made by some politicians and propagandists that, by preserving biodiversity, we can somehow preserve the whole planet's life is just a further example of our big-headed delusion. However close humanity itself may be to causing its own extinction, or at best its irrevocable disintegration, most other species will carry on regardless. It's just the delusion of our culture that we will conquer death.

I hear our non-human brethren sniggering. "Got along without you before I met you, gonna get along without you now," they sing. Most of them, the microbes, the whales, the insects, the seed plants and the birds are still singing. The tropical forest trees are humming to themselves waiting for us to finish our arrogant logging so they can get back to their business of growth as usual. And they will continue their cacophonies and harmonies long after we are gone.

Lynn Margulis is co-president of Gaia, the Society for Research and Education in Earth System Science, at the University of East London