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story:The birth of Environmentalism

scene:James Lovelock and Gaia theory

James Lovelock, creator of the Gaia theory picture zoom © Photo EFN – Environmentalists for Nuclear Energy

In 1960, a young scientist called James Lovelock invented the electron capture detector. His work with it led to the development of the Gaia hypothesis, a philosophy which has been extremely influential for the environmental movement.

The electron capture detector

The electron capture detector is a highly sensitive device for measuring air pollution. Lovelock’s work with the detector resulted in a greater understanding of the way human activities damage the atmosphere. For example, in the summer of 1967 he measured the supposedly clean air blowing off the Atlantic onto the west coast of Ireland and found that it contained chlorofluorocarbons (CFCs), now known to cause ozone depletion.

Impressed with Lovelock’s innovations, NASA invited him to join their team in 1961. He soon became involved with their quest to find evidence of life on Mars.

Is there life on Mars?

Lovelock compared the atmosphere around Mars with Earth’s atmosphere. He realised that the Martian atmosphere was stable and ‘chemically dead’, while Earth’s atmosphere contained a ‘highly improbable’ mixture of gases that were constantly circulating. The pump driving this circulation was life itself.

Gaia theory

This epiphany led Lovelock to elaborate his renowned but controversial theory, the Gaia hypothesis, in 1972. Now called the Gaia theory, Lovelock’s idea was named by his neighbour, the novelist William Golding, after the Greek Earth Goddess.

The idea that Earth was alive gained special resonance after the 1960s when space flights allowed Earth to be viewed as a complete entity for the first time. picture zoom © NASA

The theory suggests a holistic view of the world, where all life on Earth interacts with the physical environment to form a complex system that can be thought of as a single super-organism. Lovelock believes that Earth is a self-regulating system able to keep its climate and chemical composition comfortable for living organisms. In particular it regulates the chemistry of the oceans, composition of the atmosphere and surface temperature. The system includes all living organisms as well as the near-surface rocks and atmosphere.

While the Gaia theory attracted many supporters, it also received a great deal of criticism. Some argued that Lovelock’s notion of a self-regulating Earth implied that it was behaving with a sense of purpose.


In response to his critics Lovelock developed the Daisyworld mathematical model. Daisyworld is an imaginary planet on which only two species live, light daisies and dark daisies. The planet maintains the conditions for its survival simply by following its own natural processes. When the model is run, the daisy populations adjust themselves in response to changing conditions on the planet, demonstrating the principle of self-regulation.

James Lovelock's theory constitutes a new way of viewing the world within a scientific framework. While Gaia might not provide all the answers, it has an important place in the history of the development of environmental awareness.

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James Lovelock, creator of the Gaia theory
The idea that Earth was alive gained special resonance after the 1960s when space flights allowed Earth to be viewed as a complete entity for the first time.
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