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James Lovelock The Ages of Gaia. A Biography of our Living Earth,
first edition 1988, second edition 1995, 2000.
Oxford University Press, paperback, 255 pages. Reviewed by Gert Korthof, 3 Oct 2004.
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| Gaia | |||
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In his 1979 book Gaia Lovelock wrote that plants produce oxygen because it benefits life as a whole.
That version of the Gaia hypothesis was teleological (goal directed), because it involved impossible foresight and planning,
and Lovelock did not propose a mechanism.
No wonder it was strongly criticised by biologists and especially neo-Darwinists.
Richard Dawkins pointed out that
"if plants are supposed to make oxygen for the good of the biosphere, imagine a mutant plant which saved itself the costs
of oxygen manufacture." (1)
Indeed, the non-oxygen producing mutant would soon become the dominant form, and oxygen production would vanish from the earth.
"This was a final condemnation. Teleological explanations are a sin against the
holy spirit of scientific rationality." (2).
Lovelock reacted to this and other criticisms by developing the daisy model.
The daisy model was non-teleological (no goal involved).
Black and white daisies in the model regulate the temperature of the earth by reflecting few or
much sunlight,
thereby cooling or heating the earth's atmosphere.
The definition of Gaia is:
The original observation that triggered the Gaia hypothesis is that the earth's atmosphere is in a chemical disequilibrium. If methane reacts strongly with oxygen, then how can it be measurably present in the atmosphere? The cause is the constant input of methane from micro-organisms. The most dramatic feature is the level of oxygen in the earth's atmosphere. The 21% oxygen is now necessary for life, but when life originated on earth oxygen was absent. Oxygen did not arise from extraterrestrial or geological sources, but was produced 2.5 billion years ago by life itself as a toxic by-product. Eventually the rest of life adapted to oxygen. Contrary to the earth's atmosphere, the 'dead' atmosphere of Mars is the atmosphere of a dead planet. But there is more. Apart from the presence of oxygen, there is the observation of the constancy of the oxygen level over hundreds of millions of years. Any theory of life on earth, including the theory of evolution, needs to integrate this knowledge. Another factor is the constant temperature of the atmosphere of our planet.
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| The meaning of Gaia | |||
| Lovelock introduced atmospheric science into (evolutionary) biology. The lesson is that tiny micro-organisms can have an enormous effect on the earth's atmosphere. This lesson is missing in most evolution textbooks. Richard Dawkins justly criticises Gaia's self-regulating capacity, but he is not interested in the amazing effect of micro-organisms. There is neither oxygen nor atmosphere in Douglas Futuyma's textbook! (3). Strickberger however, (4) has an elaborate discussion of oxygen. When organisms have created the habitability of our earth in such a significant way it ought to be incorporated in the theory of evolution. The question remains how the constancy has to be explained. Explaining it by 'homeostasis' is not a real explanation, since there is still no mechanism. Secondly, 'homeostasis' strongly suggests a living organism, because there is no homeostasis without an organism. The statement 'maintained at an optimum by homeostasis' and this maintenance is performed by the biosphere itself" is no explanation, because it reintroduces the notion that Gaia is alive, which Lovelock rejected earlier. Homeostasis makes only sense within an organism. Indeed the expression "the atmosphere as a circulatory system" (5) reveals that Lovelock uses the analogy of the blood system and its properties. However, there is a big difference between homeostasis of the blood system and of oxygen in the earth's atmosphere. Good analogies invite good questions. Wrong analogies invite wrong questions, but at the same time could produce new discoveries. Does Daisy world explain homeostasis? An indication of Lovelock's doubt is the odd remark that his theory need not be true to be useful. | |||
| Is Gaia alive? | |||
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Both Lovelock and Margulis claimed in their earlier writings that Gaia is a living organism,
and later changed changed to claims that are more moderate.
According to Margulis, Lovelock defended that "the earth is a organism" (6).
Margulis: "I cannot stress strongly enough that Gaia is not a single organism"
(7).
And "Rather than state "Earth is alive", we prefer to say that Gaia is a hypothesis about the planet Earth, its surface
sediments, and its atmosphere" (8). Before we can answer the question Is Gaia alive?, we need to know to what life is. Lovelock recognises the need for a definition of the concept 'life'. He observes that the Dictionary of Biology has no entry for 'life'! In general biologists avoided the question, he says. However, I disagree that no one has yet succeeded in defining life. Lovelock did not know Gánti's definition. Lovelock attempts to define life, but misses the dual nature of life (metabolism-heredity). On the other hand he quotes Schrödinger's definition: living systems have boundaries and are open systems at the same time. This is a dual nature from another perspective. In the context of thermodynamics: life is a self-organising system characterised by an actively sustained low entropy. Because Lovelock overlooks the importance of 'minimal life' in defining life, he fails to give a thorough and satisfactory definition. A probable cause is his focus on planetary biology and symbiosis (life exists in communities and collectives). The lack of a good definition of minimal life prevents a good understanding of problems inherent in the origin of life. For example when discussing the origin of life, he states "The first living cells may have used as food the abundant organic chemicals lying around; also the dead bodies of the less successful competitors..."(9). However, by definition, the first forms of life could not have used dead bodies. Secondly, Lovelock seems to dismiss the criterion of reproduction for reasons unclear to me. I guess in order to maintain the idea that Gaia is alive notwithstanding the obvious fact that Gaia does not reproduce. Only individual organisms reproduce. Just because the atmosphere is in disequilibrium, improbable, anomalous and these properties are caused by living organisms, does not mean that the earth itself is alive.
Whether or not the earth is a self-regulating superorganism, the fact that
tiny creatures can influence and even create the earth's atmosphere (with huge dimensions relative
to the size of microbes themselves), is interesting enough.
I agree that the earth's atmosphere cannot be understood by physics and chemistry alone, but biology is needed
to explain its anomalous nature (chemical disequilibrium).
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| Daisy world: a computer model | |||
Lovelock developed the Daisy world computer model as an answer to the apparently justified criticism
that Gaia was teleological (goal directed). He wanted to show that ordinary natural processes
can account for the constancy of the earth surface temperature despite the increasing luminosity of the sun
during the last billion years.
Regrettably, I did not find a good explanation of the model and no information about the assumptions of the model
in this book, although there is information about the output of the computer model.
So it is impossible to evaluate his Daisy model from the information in this book.
According to Lynn Margulis the Daisy world model shows that the daisies cool their world despite the warming sun
(10).
From other sources describing the daisyworld model I come to the tentative conclusion that it is an unrealistic
model because
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| Nuclear radiation is as dangerous as breathing oxygen | |||
Two additional remarks. Radiation causes an extra amount of damage above the oxygen damage level. We cannot say "I stop breathing for some time, because I need all my resources to repair radiation damage". Furthermore, Lovelock's argument assumes 'normal' doses of radiation. Of course the body cannot deal with a high dosis of radiation during short periods of time (nuclear accidents!). Accidents are a reality of our society and so when evaluating the health risks of radiation, we cannot ignore accidents. Lovelock should have given the reader a more complete and balanced analysis of this controversial issue. To establish the basic similarity between radiation and oxygen damage is in no way sufficient to establish the safety of nuclear power plants. He should have consulted more than just one expert. Lovelock makes personal attacks on radiation biologists and government scientists. Notes
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| Copyright ©G. Korthof 2004 | First published: 3 Oct 2004 | Updated: - Notes/FR: 31 Jul 2009 |
James Lovelock is a visionary character, a colourful person and an independent scientific thinker and inventor.
Lovelock is widely known for his Gaia theory. The earth is a superorganism,
consisting of both living organisms and a non-living environment.
Gaia has the ability to self-regulate climate and chemistry of the earth.
Lovelock invented instruments to detect chloro-fluoro-carbons and found them present in the
atmosphere, but initially judged them not dangerous for human health.
Later Lovelock developed the daisy-world computer model to prove that organisms could
self-regulate the earth's climate and that daisy-world does not contradict neo-Darwinism.
He proposed ideas how to make Mars habitable,
and claimed that radioactivity is as dangerous as breathing oxygen.
