Meet Gaia

Like many female deities found in religions across the world, this Ancient Greek goddess of the Earth is feminine and nurturing. But try and cross her by refusing to live in harmony with nature, and you’ll see her ruthlessly cruel side.

The beginnings

In the 1960’s, a young scientist named James Lovelock was analysing the composition of the atmosphere on Venus and Mars. By this method, he was trying to establish whether there was a possibility of life on those planets. He and his team believed that if the composition of the atmosphere was close to equilibrium (i.e. all the possible chemical reactions have taken place), it was an indicator that there was no life, as living organisms are obliged to use the air as a source of raw materials and as a depository for their waste products. The findings supported their hypothesis; the atmospheric compositions of Mars and Venus were relatively stable, compared to that of the only living planet we know, the Earth. The atmosphere of the Earth was an extraordinary and unstable mixture of gases.

But wait. Surely it can’t be THAT unstable if the chemical composition remains relatively constant over prolonged periods of time! Life would never have developed if the pioneer plants had to continuously adjust themselves to different gases.

This paradox made Lovelock come up with a new, unorthodox theory, which when it was first outlined in 1971 was hardly well received. But recognition has grown over time. If the composition of the Earth’s atmosphere was highly unstable, but consistent, it must have been REGULATED, right?

The Theory

Lovelock used the name of the ancient Greek goddess (due to the obvious metaphorical parallels) to describe Earth ‘viewed as a single physiological system, an entity that is alive at least to the extent that, like other living organisms, its chemistry and temperature are self-regulated at a state favourable to its inhabitants’.

The concept of an Earth which is ‘alive’ seems ridiculous. But then, what is LIFE? The physicist’s answer would be:

‘Life is a peculiar state of matter that reduces its internal entropy (measure of proximity of a system to equilibrium) in a flux of free energy, and is characterized by an intricate capacity for self-regulation’.

Well, we’ve already established that Gaia does regulate itself.
The biochemist’s answer would be:

‘A living organism is one that takes in free energy, such as food and oxygen, and uses this energy to grow according to the instructions coded in its genes.’
 
The Earth certainly uses solar energy and conducts a kind of metabolism on a planetary scale. The latter part of the answer referring to genes was the argument that Dawkins employed in his book The Extended Phenotype, claiming that there is no way for genes to express themselves on the planetary scale. However, physicists have acknowledged for a long time that the microscopic properties of the atoms and their parts are linked with the large-scale properties of the universe. The evolution of the universe depends upon the properties of the atoms from which it is composed. Thus, while the planet doesn’t have a genome, its properties are manifested due to something a lot smaller and simpler.

But the neo-Darwinists (disciples of Darwin who have combined the great theory of evolution with the discoveries of modern genetics) would say:

‘An organism is alive when it can grow and reproduce; any errors of reproduction are corrected in the process of natural selection.’

That too is right, as far as our knowledge of astronomy and geophysics goes.

Some argue that Gaia is not alive like you and me, as it has no sense of purpose, can’t move by its own free will or make love. But neither can many bacteria.

At the end of the day, Lovelock isn’t asking anyone to become converts to a new Earth religion or suspend their common sense – all he is presenting is an alternative to the conventional wisdom that the Earth is a dead planet made of inanimate rocks, oceans and atmosphere that is merely inhabited by life.

And if all these arguments still fail to impress you, just acknowledge them for the purpose of the argument: Gaia is poorly and declining in health. While conventional science is attempting to heal her, it is too slow in its research and implementation. Instead, the remedy Lovelock suggests is a holistic approach.

Humans are pathogens

 Well, we all know that since Homo Sapiens started cutting down forests to create land for agriculture, invented combustion engines and decided to drill oil out of the depths of the Earth, the state of the biosphere has been going downhill. We do think about ecology, but let’s be honest, only insofar as we ourselves are concerned; no one apart from a few eccentrics cares much about any other living organisms, let alone the Earth itself.

 For the past few millennia we have believed ourselves to be God’s chosen species, but are we really more than the most destructive event in our planet’s biological history? Have we become the leukaemia of the earth, slowly but surely pushing our luck?

One might argue that leukaemic cells do not debate their destructive role, nor consider a change of behaviour that might curb their own numbers. But then we’ve got to ask ourselves how much our debating has actually achieved – it’s true that the leaders of some countries have signed some papers [1], but one only has to look at the figures to see how far we are from achieving our goals – in 2010 the European emissions of greenhouse gases are predicted to be 0.3% greater than in 2004.[2]

The rules of Gaia are such that organisms that harm their environment do not survive for long; so it’s in our own interests to help her.
 

The Dummies’ Guide to Planetary Medicine

Ecosystems = Organs?

Conventional science defines an ecosystem as ‘a stable, self-perpetuating system, composed of a community of living organisms occupying a non-living environment’. According to this view, the ecosystems don’t alter the environment, but merely adapt to it. The Gaia theory suggests that the ecosystem and the environment are tightly-coupled forces interacting with each other, with each one shaping and affecting the other.

The natural ecosystems make up the whole of Gaia. In some ways they correspond to our organs, such as the liver, the blood, the skin and the lungs. Each has its partial independence, vital to the system, but is unable to exist except as part of that system.

Homeostatic Responses

Homeostasis is an organism’s tendency to stabilize its normal body state, its internal environment. It is essential to understand that it is not a permanent, fixed state of constancy, but a dynamic state of constancy; think of dynamic equilibrium in chemistry or no net change in biology. Here are just a couple of very basic examples of the factors that Gaia has kept relatively constant for us throughout the millennia – the relative abundances of carbon dioxide and nitrogen. [3]

Carbon dioxide

Carbon dioxide is the key metabolic gas of Gaia, influencing climate, plant growth and oxygen production. It cycles through the system from its source (volcanic output) to its final sink (burial as Calcium carbonate). Its abundance in the air is dependent upon the rates at which it leaks into and is pumped out from the air.

Some ‘pumps’ out include

• Plants: the process of photosynthesis takes Carbon dioxide out of the atmosphere and fixes it as organic compounds
• Rain: Carbon dioxide dissolves in the rain, thus making it acidic, and falls on basalt rocks forming calcium bicarbonate
• Some algae (e.g. coccolithophores): take Calcium bicarbonate to make skeletons of Calcium carbonate

Some ‘leaks’ in include

• Respiration by animals and plants: we breathe in mainly oxygen and breathe out mainly Carbon dioxide, as I’m sure you all know.
• Volcanic activity: carbon dioxide is always leaking out due to volcanic activity. 
• Weathering of rocks: Carbon dioxide reacts with Calcium silicate rocks such as basalt, resulting in the products of Calcium bicarbonate and Silic acid.

Nitrogen

Nitrogen is a component of all amino acids and thus proteins, making it essential for any life. The nitrogen cycle consists of 5 important processes.

1. Assimilation: plants take Nitrogen from the soil and make organic molecules out of it.
2. Ammonification: organic matter in the soil is converted into Ammonia.
3. Nitrification: conversion of Ammonia to Nitrate by other organisms.
4. Denitrification: certain types of bacteria convert Nitrate to Nitrogen gas
5. Nitrogen fixation: soil bacteria reduce atmospheric Nitrogen to Ammonia

A good test of a homeostatic system is its ability to respond to disturbance and injury. Gaia has survived at least 3.8 billion years, having experienced in that time a full set of challenges. One of these is a particularly famous case story.

Case Study: The near-fatal marasmus

Marasmus, a condition of malignant debilitation sometimes occurs after severe shock. Metabolism and normal physiological function fade away until even the power to conduct even the minimal homeostasis required for life is lost.

Gaia as a system has on at least one occasion survived a near-fatal marasmus. Around 65 million years ago, a meteorite hit the planet [4], causing the extinction of some 90% of species present, including the dinosaurs.

It is essential to bear in mind that they didn’t die overnight, but (as it is currently believed) failed in the competition for resources in the changed and hotter world which they just weren’t adapted to.

Why are we talking about it? Gaia managed to alter her environment, increased or decreased some equilibrium points of a few systems, but survived. The homeostatic mechanisms were strong enough to maintain the environment constant enough for some of the species to survive and evolve through the newly-established selection pressures.

The Human Plague

Coming back to the metaphor, imagine a planetary physician receiving his/her old patient Gaia for a regular check-up. At first glance, she is a comfortable, older planet. However, the atmospheric Carbon dioxide is above the level believed to be acceptable for her age, and there is a suspicion of fever. In addition, the ‘skin’ surface (land) shows a number of bare patches.

Most telling of all is the great abundance of atmospheric CFCs, gases that are never made by the natural chemistry of living organisms. The physician knows that this shows the presence of a highly organised social species, one that has developed an advanced chemical industry.

As with human diseases, there can be four outcomes:

• Destruction of the invading disease organisms
• Chronic infection
• Destruction of the host
• Symbiosis: a lasting relationship of mutual benefit to the host and invader

Back to the real world then. The last outcome would obviously be in our species’ interests. There was, in fact, a time when we lived in harmony with Gaia, back when our ancestors lived in small groups of hunyer-gatherers. The moment we moved onto agriculture and began using fire (i.e. began to sustain our own personal environment at the expense of Gaia’s), the contract was broken. Now as a consequence of population growth and the development of our capacity to displace the rest of planetary life, we threaten both ourselves and our planet.

Now what?

When it was mentioned at the beginning of the article that Lovelock proposes a ‘holistic’ approach to treating Gaia, the term wasn’t really explained. ‘Holistic’ means relating to or concerned with wholes or with complete systems, rather than with the analysis of, treatment of, or dissection into parts; holistic medicine attempts to treat both the mind and the body.

The role of doctors often involves prevention, rather than the treatment of diseases, by pointing out the ways in which a patient can make his or her life healthier. To be honest, it’s always the same: no smoking, minimal drinking, physical exercise, good diet and sufficient sleep. In the same way, Lovelock argues, the role of a good planetary physician (we’re back to the metaphor now) is to persuade the human population of the advantages of living well with Gaia and of taking care of it in a way similar to the way we would take of our bodies.

We must be cautious of the ‘cures’ designed for Gaia. Recent suggestions have included:
• Applying medication to oceans, to stimulate the growth of algae, which would remove the excess Carbon dioxide from the air.
• Irrigating the oceans with Iron chloride solutions, dispensed from supertankers, thus fertilizing the algal blooms and removing enough Carbon dioxide from the air to allow us to continue burning fossil fuels.

These seem like an equivalent of taking thyroid hormones in the hope of increasing metabolic rate. What these quick fixes ignore is the fact that both the human body and the planet consist of more than the one mere system that is of interest to us, in this case the carbon cycle and metabolic reactions. To attempt control of the whole self-regulating body from outside by increasing or decreasing a feedback loop in these multiple feedback systems is rarely successful, and carries with it a risk of dangerous and unpredictable instability. Does DDT ring a bell?

We all know what it is that we have to do – curb greenhouse emissions, turn the lights out, etc. And we better start acting sooner rather than later, or we’ll damage the planet to the extent that keeping the environment acceptable for habitation will become our full-time job (think of a patient who needs full-time care because many of its systems are run down).

And to conclude…

If we accept that we humans have a finite individual lifespan and that no one can ever be immortal, then maybe we should keep in mind the thought that our species also has a limit for its span on Earth.

Gaia is a big girl and has seen worse. She will get over this somehow, if only by getting rid of the annoying parasites that have been exploiting her resources for the past few millennia. Gaia will survive. We might not.

Endnotes
[1]http://news.bbc.co.uk/1/hi/sci/tech/4269921.stm
[2]http://environment.guardian.co.uk/climatechange/story/0,,1933867,00.html#article_continue
[3]Stating that the relative abundances have been kept constant is somehow misleading – the Earth’ atmosphere has changed a great deal since its ‘birth’. Its general composition hasn’t, however, changed much since mammals and our far-fetched ancestors evolved.
[4]There is still some debate as to where exactly it landed, but it’s generally believed to have been around present-day Mexico.

References
‘The Revenge of Gaia’ by James Lovelock
 
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