Non-Fiction Reviews

Gaia

Published on December 6, 2023

Gaia 1

The earth as seen from Apollo 17 (1972)

‘Viewed from the distance of the Moon, the astonishing thing about the Earth, catching the breath, is that it is alive,’ wrote the biologist Lewis Thomas in 1974. His words were quoted prominently at the start of James Lovelock’s book The Ages of Gaia. While working with NASA in the mid-1960s, Lovelock developed the now famous Gaia hypothesis, the most fertile of all the scientific insights that have flowed from the sight of the whole Earth from space. ‘The outstanding spin-off from space research is not new technology,’ he wrote when introducing the first Gaia book, Gaia: A New Look at Life on Earth, in 1979. ‘The real bonus has been that for the first time we have had a chance to look at the Earth from space, and the information gained from seeing from the outside our azure planet in all its global beauty has given rise to a whole new set of questions and answers.’ Lovelock felt that this also took humankind right back to the ancient concept of Mother Earth: ‘Ancient belief and modern knowledge have fused emotionally in the awe with which astronauts with their own eyes and we by indirect vision have seen the Earth revealed in all its shining beauty against the deep darkness of space.’

The Gaia hypothesis has been called ‘the most widely discussed scientific metaphor of the Age of Ecology’. As originally formulated, it proposed that ‘the Earth’s living matter, air, oceans, and land surface form a complex system which can be seen as a single organism and which has the capacity to keep our planet a fit place for life.’ More simply, ‘the Earth . . . is actively made fit and comfortable by the presence of life itself ’. Even more simply, the Earth is alive. Despite initial resistance from sections of the scientific community, Gaia has consistently made headway, going from hypothesis to scientific theory and acting as a model for holistic thinking in the sciences. ‘Can there have been any more inspiring vision this century than that of the Earth from space?’ exclaimed Lovelock, looking back. ‘We saw for the first time what a gem of a planet we live on. The astronauts who saw the whole Earth from Apollo 8 gave us an icon that has become as powerful as the scimitar or the cross.’

The living Earth

‘Our recognition of living things, both animal and vegetable, is instant and automatic,’ James Lovelock has observed. As early as 1969 the microbiologist René Dubos related how the sight of the Apollo 8 Earth images ‘made me realize that the Earth is a living organism’. Eugene Odum, the pioneer of ecosystem ecology, used the Earthrise picture in his textbook Fundamentals of Ecology and kept a poster of it on his office wall. Dubos however went further, suggesting that the Earth’s natural systems were self-repairing, and the Earth adaptable and resilient. Humankind was part of all this, not separate from it: ‘Earth and man are thus two complementary components of a system, which might be called cybernetic, since each shapes the other in a continuous act of creation.’ Dubos developed what he called ‘a theology of the Earth’, arguing that ‘a truly ecological view of the world has religious overtones’. Lovelock appreciated Dubos’s way of thinking, particularly what he called the ‘concept of man as the steward to life on Earth, in symbiosis with it like some grand gardener for all the world’.

While whole Earth thinking in the natural sciences was given a boost by the sight of the Earth, it was not created by it. In the 1950s the palaeontologist and philosopher Loren Eiseley contemplated the ways in which science had come to understand the world as the product of gradual natural processes, rather than of Old Testament style cataclysms. ‘Like the body of an animal,’ he suggested, ‘the world is . . . destroyed in one part, but is renewed in another.’ Donald Worster has identified a long-standing tradition of ‘seeing the Earth as a single living organism’, and observes: ‘that the Earth was sick, and that the sickness was our doing, was a spreading idea after World War Two’. This tradition had been revived earlier in the twentieth century by the agriculturalist Liberty Hyde Bailey, who wrote: ‘The Earth is holy …. We are here, part in the creation.’

Humankind, he felt, had been given dominion but not ownership of the Earth; sadly,‘our dominion has been mostly destructive’.He even wrote of ‘the mothership’ of the Earth, although he was referring to motherhood rather than spaceships.

In the 1920s the Russian biologist Vladimir Vernadsky had developed the concept of the biosphere. Vernadsky too had been inspired by the view of the Earth from space, although in 1926 he had to imagine it. His book The Biosphere opened with these words: ‘The face of the Earth viewed from celestial space presents a unique appearance, different from all other heavenly bodies. The surface that separates the planet from the cosmic medium is the biosphere.’ Defining it as ‘the envelope of life where the planet meets the cosmic milieu’, he wrote: ‘the biosphere plays an extraordinary planetary role . . . the Earth’s structure is a harmonious integration of parts that must be studied as an indivisible mechanism.’ Lovelock did not know of Vernadsky’s work until later; a full English translation was only published in 1998, when he was hailed as ‘the first person in history to come to grips with the real implications of the fact that Earth is a self-contained sphere’. The term ‘biosphere’ went back still further, having been used in the late nineteenth century by the Austrian geologist Eduard Suess. At the start of his book Suess imagined an observer from outer space ‘pushing aside the belts of red-brown clouds which obscure our atmosphere, to gaze for a whole day on the surface of the Earth as it rotates beneath him’. He called his book The Face of the Earth.

Visual thinkers, it seems, are prone to big ideas. ‘When I first saw Gaia in my mind I felt as must an astronaut have done as he stood on the Moon, gazing at our home, the Earth,’ wrote James Lovelock, recalling the origins of the Gaia hypothesis. Still at that point no one had seen the whole Earth. The Gaia hypothesis was, however, triggered by the space programme, in what at first seems an unlikely way: by the search for extraterrestrial life.

In the earlier 1960s Lovelock had been employed by NASA to design experiments to detect life on Mars, for a Mars lander to be called Voyager. Lovelock proposed that rather than looking for life directly in the soil, Voyager should look for it indirectly by testing the composition of the atmosphere. His ideas were rejected; so was the Voyager project itself by Congress when a Mars orbiter seemed to show that Mars was all rock and desert. Scientists had to make do with data from Earth-based infrared telescopes, which in 1965 showed that the atmospheres of Mars and Venus consisted mainly of carbon dioxide; there was none of the exotic chemistry found on Earth. These results confirmed Lovelock’s hunch that a live planet would have a live atmosphere; as he later put it, ‘the dead are more stable than the living.’ The health bulletin on Mars, then, was ‘stable, but dead’. But if so, what was keeping the Earth’s much more complex atmosphere stable and fit for life? Discussing the question with the astronomer Carl Sagan, Lovelock learnt that the Sun had been growing gradually hotter over the lifetime of the Earth, yet he knew that the Earth’s temperature range had remained broadly stable. This was Lovelock’s eureka moment: ‘Suddenly the image of the Earth as a living organism able to regulate its temperature and chemistry at a comfortable steady state emerged in my mind.’

Lovelock’s thinking as it emerged from his background in the physical sciences was fleshed out in collaboration with the Boston microbiologist Lynn Margulis, whose research indicated that all forms of life on Earth had developed from the most primitive single-celled organisms. Her grand thesis was that life on Earth had developed not through competition alone but through the relationship between different forms of life, which she called ‘symbiotic evolution’. Margulis also had a space connection, having earlier been married to Carl Sagan. Lovelock’s suggestion that the composition of the atmosphere was influenced by biological activity fell on deaf ears at a conference at Princeton in May 1968. Back home in his Wiltshire village, Lovelock discussed his concept of the Earth as ‘a cybernetic system with homeostatic tendencies’ with his neighbour, the novelist William Golding, wondering what to call it. ‘I need a good four-letter word,’ he mused. Golding suggested ‘Gaia’, the Greek Earth goddess. The Gaia hypothesis was first published in Carl Sagan’s space journal Icarus and in the pages of Stewart Brand’s CoEvolution Quarterly.