To Discover a Living Planet
Who-how-where about the Gaia Theory of James Lovelock
This article by Jon Bjarnes is based on his book ‘Leve som elver’
published by Artemis Forlag in Norway 2002.
Wiltshire, Southern England 1970. Two men are out walking in the rain.
They are neighbours and have something to talk about. One of them,
William Golding, is close to 60. 14 years later he is going to get the
Nobel price in literature for his book ‘Fluenes herre’, a story about
English school boys who got stranded on a desolate island and became
quite gruesome..
The other has just passed 50. His name is James Lovelock, he is
originally a medical doctor, but has worked also in other fields and has
among much else invented an electronic detector that is used to detect
traces of chemicals created by man in tiny concentrations. At the end of
the 1950’s this detector was used to identify traces of insecticides
like DDT in most living species. Later Lovelock used it to identify
chlorfluocarbons in the Antarctic atmosphere. This discovery became the
basis for the discussion whether gases made by man could destroy the
ozone layer protecting the Earth from ultraviolet radiation from the sun.
Life makes the environment favourable for life
Now, however, Lovelock has something new on his mind. Some years earlier
he got an idea. And this idea he is now together with some others
working to develop into a theory. But still they have no name for the
theory. Perhaps Golding might have a suggestion.
Lovelock explains it in general terms: The necessary conditions for life
on Earth, as for example temperature and the chemical composition of the
sea and the atmosphere, are actively regulated by living creatures. This
regulation makes the system fairly stable and causes conditions in
general to be favourable for the continuation of life on the planet. The
regulation may in fact remind us about the regulation we observe in
living beings. Perhaps the Earth in a way is a living being?
But, what about the name? Lovelock would prefer a short name for his
theory of no more than four letters.
“Gaia”, suggested Golding.
Gaia was the ancient Greek name for Mother Earth, which gives life, but
may also take it.
Lovelock accepted it on the spot. The living Earth had got a name, or
perhaps rather found back to its old name.
Why is there water on the Earth?
We may safely assume that the first biological life on Earth developed
under water. No living organisms can exist without water. I remember I
was told that I consist of 70 % water. The same holds for the surface of
the Earth. That makes our planet an exception in the neighbourhood. No
one of the other planets in our solar system have more than traces of
water. But our Earth is blue!
And wet. But why? Nobody is able to give the complete explanation. But
briefly told the story runs like this:
If we do like the astronomers and assume that time and space came into
being through a giant explosion some 12-15 billion years ago, we are
going back to a point in our galaxy some 5 billion years ago, and a
supernova had just exploded. The debris from the explosion is looking
for something to attract to. What we now call the Earth arises, first as
a cloud of gas – poorly organized we may say. The radioactive lump
rather gives a nasty impression, but it pays no heed to our depreciating
ideas, future as they are. In time gravitation and centrifugal forces
find time and occasion to sort the content. The Earth gets a body of
fixed elements and an atmosphere of gases. It starts to look like
something, but it is still a long way ahead.
The players in this work of assorting it out, are atoms. Atoms are of
different kind which later have got names and numbers, and today are
called elements. They continually form different combinations with each
other. Two of the most common elements are oxygen and hydrogen. Both are
gases. Hydrogen is the lightest of them all. Great quantities of them
are available. They meet and connect to each other, three and three they
form water, a liquid we know as H2O which is the material for tears and
blood.
As it has been told, a cloud arose from the earth and watered its whole
surface.
In addition to this water that was home produced the Earth also receives
ready made water from the neighbourhood. It is still quite a lot of
disorder in the solar system and there is a heavy incidence of comets.
Small and large heavenly bodies crash into the planets. Many of them are
like snow balls, consisting mainly of ice crystals.
Well. Time is getting older. We are now arriving at a time starting some
4 billion years ago. Our planet has got water and seas. The same applies
– according to space scientists – to our neighbouring planets, Mars and
Venus. They have also taken part in the snow ball war of the comets and
have home based hydrogen and oxygen atoms have found each other.
Looking some 2 billion years forwards. Let us think there has been a
game going on: which of the neighbouring planets is the best to keep the
water? Now the game is over. Mars and Venus turn around as arid planets
in the evening sky. Only the Earth has got a pale blue colour and is as
wet as ever before. Something must have happened.
Looking back, we are once more some 4 billion years earlier than our
present 21st century. Water has collected in deep basins in the crust of
the Earth. It is a lot of water. We may indeed call it a sea. The sun
rises above the horizon in the east, looking down into the depth of the
sea, creating sloping walls of light. We may imagine how it changes
during the day as the planet turns itself against the rays of the sun.
Then, something impossible happens, something untold and unfathomable.
Nobody really knows and we have to take all kinds of reservations. It
must have been something not easy to grasp. Atoms have come together and
certain molecules have united into chains in new and previously not
tested ways. And when one chain of molecules is broken down, new chains
are forming. A kind of creature is forming. And when the sun shines, the
creature absorbs certain substances, excreting some, but combining
others and building up a surplus. The creature is growing. But that is
not all to it. It divides into two. And these two again divide into four.
All of them are digesting the light from the sun, and they increase.
Life has begun.
What does this life have to do with preserving water on the planet? It
is here Gaia comes into being, at least according to James Lovelock. He
thinks that water and life owe it to each other that they still are on
our planet – and of course that we are there.
Explanation follows. But to start with the beginning, we have to take a
look at the atmosphere on our planet to be able to compare ourselves
with our neighbouring planets.
Are there any citizens of Mars?
Washington May 25th 1961. The new American president John F. Kennedy
presents an extraordinary speech to Congress about the challenges facing
the USA. There are some. Communists are pressing forwards in country
after country, the race against the Soviet Union in military armament,
never easy to tell who is in front, and now the upcoming rally into
space, the largest arena of all. A few weeks earlier Jurii Gagarin had
climbed into space with the rocket Vostok I and landed safely after two
hours in space as the first man to escape the gravity of the Earth. And
before that the Russians had succeeded landing a probe on the moon.
In 1961 the Americans felt really at a bottom. But Kennedy mobilizes in
his speech the USA to meet the challenge. There are no limits to what a
free society like the Americans can achieve only they go together. And
he ambitiously sets the aim: within the decade of the 1960’s an American
will land on the moon, and he will also safely return to the earth.
The first consequence of this presidential message was a great surge in
American research in space science and technology. During the 1960’s the
American space engagement grew rapidly. The expedition to the moon was
its first gigantic project. But this was only the first station, and the
Russians had already been there. What about Mars?
For such future prospects the free world needed the best brains
available. One of these was the Englishman with a medical education and
the invention of the electron-detector, i. e. our man, James Lovelock.
His task in NASA was to figure out the chances that we might encounter
life on Mars. If we managed to land a space probe safely at the surface
of the red planet, how should we ascertain whether there was life there?
During the fall of 1965 he was sitting together with the philosopher
Dian Hitchcock in Pasadena, California, trying to figure out how to
proceed. The two of them took as their starting point that it would be
possible to measure the contents of the atmosphere of a planet without
having to go there. Perhaps it might be possible to predict the chances
for life on Mars by determining which gases the atmosphere contains.
All living beings exchange matter with the surroundings. In order that
this may be possible there must be at least one medium in which this
exchange may take place. And since there so far were no signs of water
on Mars, Lovelock and Hitchcock thought that signs of such an exchange
might be found in the atmosphere of Mars.
The two of them accordingly started comparing the atmosphere of
different planets. The Earth is in this respect markedly different from
the neighbouring planets, Mars and Venus. While the atmosphere of the
Earth is dominated by nitrogen and oxygen, the atmosphere of the other
planets consists mainly of carbon dioxide. From a chemical point of view
the atmosphere of the Earth is instable: It contains reactive gases and
has a great potential to react with other substances. The atmospheres of
Mars and Venus, however, are chemically much more stable. Those gases
which have the potential to react with each other, have already done so.
The reactive gases in the atmosphere of the Earth are in general
continuously being excreted by living beings. It there is life on Mars
we would expect its atmosphere to contain such reactive substances. But
this was not found. In 1968 the two scientists therefore advised NASA
that they should save their efforts looking for living beings at Mars.
Today several unmanned expeditions have visited Mars and so far none of
them have found signs of life, as Lovelock and Hitchcock had predicted.
An improbable atmosphere
If he did not quite manage to convince NASA about the conditions on
Mars, Lovelock had got something new to think about.
From a chemical point of view the atmosphere of the Earth is quite
improbable. It contains diverse substances that ought to have reacted
with other substances in the air or at the surface of the earth. The
explanation is not that these substances do not react with each other,
but that living beings continually release them anew into the atmosphere.
The atmosphere of the Earth was accordingly not created one time for
all. The remarkable fact was that its composition was that stable. As
far as Lovelock could ascertain the content of oxygen in the atmosphere
had been at almost the same level for 200 million years. What could be
the explanation of this remarkable stability?
Lovelock decided to have a great look at this earthen planet. Perhaps
there are examples of other stable systems that only may be explained if
we take living beings into consideration?
He found a lot of them. The weather is one of them. In spite of some
variations the temperature has been more or less the same for almost 4
billion years. During this time the sun has increased its radiation 25
%. When the temperature of the earth has not increased correspondingly,
it is because of how the Earth has ‘answered’ through ‘regulation’ of
the greenhouse effect.
As we now so well know through the debate about manmade climatic effects,
certain gases in the upper atmosphere will act like the walls in a
greenhouse. The light from the sun is allowed in, but the heat is
checked on the way out. Most well known of these greenhouse gases is
carbon dioxide. But there are several others as well. All gases with 3-4
atoms per molecule will have a similar effect.
The day life on Earth started, the atmosphere of the Earth contained a
large percentage of carbon dioxide. But in time the green plants
developed. They eat carbon dioxide. And they convert it into new carbon
compounds which become plant material. This plant material subsequently
enters the soil and later become carbon containing rocks. The content of
carbon dioxide in the atmosphere has as a result decreased, from perhaps
10 to 30 % when life first arose on the planet, to only a small fraction
of a percent now.
The art to conserve hydrogen
And then, it is the question of how to keep the water? As we have seen
there is reason to believe that there was water on all the planets,
Mars, Venus and the Earth, from the beginning. But water is a compound
that not necessarily remains forever, and especially not at young
planets with lots of volcanic activity.
It is possible to break the connection between the oxygen and the two
hydrogen atoms in the water molecule. Hydrogen is the lightest gas of
all, and if it is set free it will just vanish into the upper part of
the atmosphere and into space. The gravitation of the planets is not
strong enough to keep it.
This is what might have happened to our neighbouring planets. Volcanic
activity produced a lot of lava and at the surface this lava hardened
into new rocks. These rocks contained minerals which reacted with the
oxygen in water, releasing the hydrogen that would simply escape. In a
matter of time more and more hydrogen vanished into space, and there
simply would not remain sufficient to produce new water.
According to Lovelock, the same thing might have happened at the Earth,
if not life had taken a part in it. The free hydrogen reacted with
organic material, either as organic refuse or living micro organisms.
Bacteria were eager to colonise the volcanic stones and they knew how to
bind the hydrogen and keep it trapped. Living beings thus managed to
take care of the hydrogen and thereby preserve water on the planet.
The more Lovelock searched, the more examples he found. Here is not the
space to list them all, but you will find them in his books we give
references to. It looked to him that life was involved, directly or
indirectly, in all the essential chemical circulations of the planet,
either to start them, or if it was necessary to keep them going. And
apparently this effect of living beings had a bearing on the sum of
these processes, keeping them surprisingly stable.
Next question was: what does this mean? Lovelock had an idea: this
reminded him of something he had seen before.
As in the body, so also on the Earth.
What is life? What is actually characterising something alive? And what
is making us different from something that is not alive?
In 1972 James Lovelock was ready to publish for the first time his idea
that the Earth was a kind of organism.
If he had been hoping for a fast recognition he should have let it be.
But he felt the idea was sound and that it might be important.
The studies of the chemical circulations of the Earth and how
temperature was stabilised reminded Lovelock of properties of belonging
to a human organism which none of us will deny being alive. James
Lovelock had a medical education and a doctorate in medicine. In
medicine it is common knowledge that there are a large number of
self-regulating systems. The temperature may increase, but not too much,
the content of various minerals in the body fluids is kept relatively
constant, etc. We have a common name for this the somewhat unmusical
name of ‘homeostasis’. Homeo means the same and stasis means state. In a
dictionary we find it defined as a ‘physiological equilibrium of the
organism’ where several different processes take part working together
to provide stability. If we look at the separate parts of the body, for
example the glands, these have the task to provide the body with
specific substances. If there is too much or too little of one of these,
the organism will suffer. The activity of the different organs therefore
has to be regulated. For this purpose the organism utilises a complex
system of feedback mechanisms. In general a feedback mechanism in the
body functions this way: if a gland for example is producing too much of
a hormone, another organ will react and produce something that will
reduce the activity of the gland to keep the hormone production stable.
Similar regulating effects arise when it is not the internal state, but
changes in the outside environment that causes a threat to internal
stability. When it gets warm we start sweating and the blood vessels in
the skin dilate to let more heat escape from the body. And when it gets
cold the blood vessels contract to keep the warmth in the body, and we
start trembling to increase muscle work and the combustion of fats and
carbohydrates in the body. As a result we keep the body temperature
fairly constant whether it is a higher or a lower temperature outside as
long as this is within reasonable limits. The body is a self-regulating
system where all the parts or part systems respond to such regulation.
It was systems with such properties Lovelock thought he had found
evidence for in the great circulations of the Earth. The chemical
circulations of the planet depend on the activity of large numbers of
living organisms. The sum of all this activity creates a system which
keeps itself in order. The living beings themselves contribute to create
a stable environment, a kind of homeostasis of the Earth. This means
that the Earth itself behaves like a living organism where living beings
play essential parts.
What is life?
In large parts of the scientific world this was, to say it mildly, not
very proper science. The reaction from most academic establishments was
silence. But the idea somehow did take hold and had an appeal both
outside and inside proper academic circles. Slowly also the critics came
out. We shall take up some of their arguments here.
First of all, said the critics of Lovelock, it was not possible to claim
that the Earth did correspond to our criteria for life.
Although most of us have intuitive ideas about what makes living beings
differ from what is not alive, the definition of ‘life’ raises some
problems, and it may sometimes be difficult to decide whether something
is alive or not. At the beginning of the 1970’s when Lovelock wrote his
first articles about Gaia, the following criteria were generally
accepted as crucial to tell whether a being was alive, or not. First of
all it had to have an organised structure. That might possibly be
accepted for our planetary globe. The second criteria were that it had
an exchange of matter with the surroundings. That could not easily be
said about the Earth, although it did exchange energy with the
surroundings, receiving light from the sun and radiating thermal energy
into space. But it was at the third point Gaia really failed. To be a
living being Gaia had to propagate itself, either by cell division or by
having ‘sex’ with a neighbouring male planet.. If not, they argued, Gaia
could not be alive.
The answer of Lovelock to these arguments was that these criteria were
formulated by biologists studying animals and plants, fungi and micro
organisms. Gaia might well be alive, said Lovelock, although it did not
have all of those properties we find studying living beings in earthly
biology. (A quarrelsome person might have said that Gaia is not alone in
being without sexual partners to propagate, what about a man who has
been sterilised or a woman who has passed the menopause. It may be too
early to write out a death certificate for such reasons!)
Perhaps more serious arguments came from scientists who took Lovelock’s
idea more seriously. They wanted him to reformulate his main thesis. He
had originally postulated that the conditions for life on this planet is
“actively regulated” by living organisms. The critics asked what he
meant by this: Did Lovelock actually believe that for example micro
organisms anticipate ecological problems and plan their activity to
neutralise these.
Lovelock had never really meant it that way, but he realised the critics
had a point. He refined his theory working further on developing models
fro self-regulating systems and developed a new version of his original
idea. The Earth is a system where the development of living organisms
takes part in regulating the environment, including the climate and the
chemical composition of this environment.
The Whole organises the parts
While Lovelock at first had described the living beings as active
partners in the self-regulation of the planet, he now states that the
Earth as a whole is regulating itself. In its present form the Gaia
theory postulates that the planet is a self-regulating system where
living beings are automated parts of these larger systems. The
blue-green sea weeds in the ocean do not plan to produce lots of oxygen
in order that this later may support higher forms of life. It only
happens this way, and not differently. It this is not due to chance, the
kind of law that makes this probable and preserves stable conditions
over very long time, must somehow depend on properties of the whole
system. Lovelock substantiates this by developing models of an imaginary
planet with simplified ecosystems. The system acts on its parts. The
parts have their parts to play, and it is the whole that organises them.
The behaviour of the individual creatures are dependant on the
environment they themselves are parts of.
Such perspectives provoked arguments of a third type. The behaviour of
living beings already had their explanation, and this was quite
different.
It is a long tradition in science to explain great things from small
things. This principle is termed reductionism because it gives
explanations which reduce something to something else. A snow crystal
for example may be explained on the basis of frozen water molecules. As
regards explaining how living beings behave it is today believed this
can be done on the basis of the genes. The instincts that make living
beings behave as they do is explained by their urge to propagate. And
the aim of propagation is preserve the genes and make them multiply.
Some have gone so far to talk about ‘egoistical genes’ and claim that
they use the individuals for their aim that is to preserve themselves
through the next generations, in what we have to call an atmosphere of
sex and violence. Nature is a fight for survival, and just some breeding.
According to the Gaia theory of Lovelock, this can not be the whole
story. It is no guaranty that a kind of organism which is spreading its
genes as effectively as possible, will become a success in evolution.
Such an organism will put no limits to its success. All species affect
their environments in different ways. All of them create waste and no
one can live from their own refuse. They therefore risk creating a
situation that is dangerous fro themselves. In addition to spreading
their genes in an effective way, Lovelock adds one condition: they must
not change the environment in a direction that is hostile to life. If
one specie should be so dominating that the environment is threatened,
it will be decimated. If you do not function in the context of the whole
it is no place for you.
From part to the whole
In the science of reductionism it is customary to try to understand
things on the basis of the parts they consist of. In Lovelock’s approach
it is significant to try to understand things by concentrating on the
wholeness of which they are parts. The difference has to do with a
difference of perspective. The problem is that it may be hard to
determine which perspective is right and which is wrong. The question is
perhaps what we really are ready for.
Now soon 40 years after the first articles were published the idea of
the Gaia theory has at least reached a very great number of people. A
Google search in February 2008 gave 186 600 hits on ‘Gaia theory’. A
search on books available on the internet gave 718 books – all more or
less inspired by Lovelock. We cannot believe otherwise that that the
debate will continue
Jon Bjartnes
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