Is the Gaia theory a good idea?

Materials World magazine
,
1 Jun 2006

Imagine you are a student with GCSEs in geology, geography and biology and view the massive white cliffs of Dover on returning from a school trip to France. You would be impressed by the sheer scale of the cliffs and would recall that much of Southern England consists of chalk, as does a large part of France. You would know that chalk consists mostly of the carapaces and skeletons of minute marine organisms. Much limestone also has an organic origin, so it will be obvious to you that life has a profound influence on the Earth’s landscape.

The carbon in the calcium carbonate, the main ingredient of chalk and limestone (and coral reefs), has been extracted from the sea and the atmosphere, and this sequestration is augmented by the formation of the fossil fuels – coal, oil and gas, which also owe their origin to living organisms. Thus life processes are responsible for the carbon in the atmosphere (mostly as carbon dioxide) being kept to a very low level.

Another form of life – green plants – is responsible for the oxygen which constitutes about 21% of the atmosphere, and for maintaining it at that level in spite of the many processes, for example, combustion, which serve to diminish the concentration of this highly reactive element.

 

The Gaia theory

All these, admittedly, amazing facts would be known to an intelligent sixth-former, but it is just this information which prompted James Lovelock in 1979 to propose his now highly-regarded Gaia hypothesis. This assumes that if you take all the living things on the Earth together it is possible to regard them as a coherent whole, a sort of super-organism which takes over the management of its inanimate environment on a global scale.

Gaia maintains the environment constant, much as a human body keeps its temperature constant and its own internal environment in balance. In other words Lovelock claims that Gaia is subject to a form of homeostatic regulation.

However, Richard Dawkins has pointed out that homeostatic adaptations in individual bodies evolve because those with improved homeostatic apparatus pass on their genes more effectively than those with inferior homeostatic apparatus. There being only one Gaia, no such competition and evolution are possible, so the analogy breaks down.

Dawkins has also suggested that the Gaia Hypothesis is teleological, and that it contains the suggestion that plants produce oxygen because it benefits life as a whole. Were we to discuss Gaia in terms of the Anthropic Cosmological Principle then it would fall within the ‘strong’ rather than the ‘weak’ classification, that is, that the Universe evolves in conformity to an overall design.


Global warming and nuclear power

Lovelock has recently written another book, The revenge of Gaia: why the Earth is fighting back – and how we can save humanity. He concentrates on the very real threat of global warming and he strongly supports nuclear power as a partial solution to this problem.

Unfortunately, he continues to personalise Gaia – note ‘revenge’ in the title. This is how he describes mankind’s prodigal use of fossil fuels, ‘With breathtaking insolence they [that’s us] have taken the stores of carbon that Gaia buried to keep oxygen at its proper level and burnt them. In so doing they have usurped Gaia’s authority and thwarted her obligation to keep the planet fit for life…’.

It is hard to take Lovelock seriously when he writes like that. I hope to return to Gaia in a future column and to describe how microscopic life played a part in the creation of some natural nuclear reactors almost two billion years ago.

 

Further information

Gaia theiory

The Revenge of Gaia: Why the Earth is Fighting Back – and How We Can Still Save Humanity by James Lovelock