The Gaia Theory: The Earth as a Single System


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The Earth from space: Courtesy NASA/Goddard Space Flight Center

The Gaia hypothesis, which takes its name from the Greek word for the Earth, was set out by the climate scientist James Lovelock in 1979.

Lovelock initially worked with NASA in attempts to identify whether life existed on Mars.

It was the contrast between the static nature of our neighbouring planet and the dynamism of our own which led to the development of what has come to be known as the Gaia theory.

What is the Gaia Theory?

The Gaia theory regards the earth as, in essence, a single organism, and everything on the planet as a part of that organism. This does not merely mean all living things, or even all organic matter, but postulates that the planet, with its rocks, plants, animals and atmosphere, is essentially what the Gaia Theory website describes as “a single, living, self-regulating system.” The implications of this are that all the various components of the Earth’s system play a part in regulating the overall biosphere so as to maintain an optimum situation for the living system. Various feedback mechanisms operate so as to maintain the earth as a place where life can continue – for example, atmospheric temperatures have adapted to overcome increasing incoming radiation from the sun. Temperature is not the only factor affected. The Gaia theory also looks at other variables such as the salinity of the oceans and the hydrological cycle (which affects rainfall). It should be noted, however, that not all scientists accept Gaia without question. A discussion in the Open University course Earth and Life notes that there are distinctions between the balances within organisms and the physical feedbacks which can also operate. Demonstrating the Gaia Hypothesis >>

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