by Noel Charlton
Institute for Environment, Philosophy & Public
James Lovelock has developed the "Gaia Theory" over the last
twenty-five years as a scientific claim that the earth’s "biota",
tightly coupled with its environment, acts (and has acted since life
on earth developed any complexity) as a single, self regulating
living system in such a way as to maintain the conditions that are
suitable for life. The system includes the near-surface rocks and
atmosphere. In particular, it regulates the chemistry of the oceans,
composition of the atmosphere and surface temperature.
More about the theory
Lovelock was working with NASA in the 1960s as a consultant to the
"life on Mars" Viking spacecraft project. Questions about whether
Martian life, if any, might be in any way comparable to life on
earth, about how life can be recognized, indeed, about what life is,
led him to see that a reduction or reversal of entropy in a planet’s
systems would necessarily be a sign of life. In particular, the
atmosphere of a planet with life would be different from that of a
dead planet. The consequent reassessment of earth’s own atmosphere
revealed it to be a "highly improbable" mixture of gases which could
only be maintained if it was "manipulated on a day-to-day basis" by
life on the surface. And so the hypothesis was born.
Lovelock tells the story of how the Gaia hypothesis was named.
Walking with novelist neighbor William Golding, he explained his
excitement about the idea. Golding, thinking of the ancient Greek
earth-mother goddess and of her dual character of caring supporter
of beings who "fit" and ruthless annihilator of those who do not,
suggested the name. Lovelock heard Golding as saying "gyre" and,
thinking of cyclical weather-systems or the behavior of circling
birds, thought it was not a bad idea. The two continued at cross
purposes until Golding said:
"I don’t know what the blazes you’re
talking about, Jim….". As Lovelock said (Schumacher College, 1996)
"It has caused quite a lot of misunderstanding but you don’t turn
down a gift like that from a wordsmith like Golding."
The Gaia theory suggests that, in some sense, the
earth is "alive".
"I recognize that to view the
Earth as if it were
alive is just a convenient, but different, way of organizing the
facts of the Earth. I am of course prejudiced in favor of Gaia and
have filled my life for the past twenty-five years with the thought
that Earth may be alive: not as the ancients saw her—a sentient
Goddess with a purpose and foresight—but alive like a tree. A tree
that quietly exists, never moving except to sway in the wind, yet
endlessly conversing with the sunlight and the soil. Using sunlight
and water and nutrient minerals to grow and change. But all done so
imperceptibly, that to me the old oak tree on the green is the same
as it was when I was a child."
(in "Gaia: The Practical Science of
Planetary Medicine", Gaia Books Limited, London, 1991, p.12.)
The idea of a living earth is ancient.
"We shall affirm
that the cosmos, more than anything else, resembles most closely
that living Creature of which all other living creatures, severally
or genetically, are portion; a living creature which is fairest of
all and in ways most perfect."
Gaia, goddess and earth mother, the
Anima Mundi - the "world soul", the idea of "spirit" in things - we
have only lost this understanding since Descartes and the coming of
objective science. There were some advocates of a living earth even
in the scientific period: James Hutton (earth as a super-organism, a
physiological system), Lamark, Goethe, Humbolt and the (little known
until recently) Russian scientist Vladimir Vernadsky who introduced
the concept of the biosphere, recognized matter as "living", life as
"a geological force" and the atmosphere as an extension of life.
Evidence and an example
Lovelock claims that there is strong evidence to suggest an overall
systemic control of the earth’s,
The processes are complex and the
following notes are simplistic reductions.
there has been a 25% increase in heat from the sun
since life began but surface temperature has remained approximately
the present highly unstable mixture of reactive gases
(79% nitrogen, 20.7% oxygen, 0.03% carbon dioxide with traces of
methane and other gases) could not be maintained without constant
replacement or removal by the biota. The early earth had an
atmosphere with more carbon dioxide and, at that stage, the
consequent greenhouse effect warmed the earth beneficially.
Subsequent increase of methane, then oxygen - all produced by biota
and cycled through oceans and rocks has been maintained by evolving
species. Now carbon dioxide is minimized in the atmosphere by
biological pumping down of carbon. Without greenhouse gases our
present surface temperature would be about minus 19C.
has been maintained at about 3.4% for billions of
years. Cells cannot tolerate salt concentrations much above 5%.
Salinity is at least partly controlled by evaporate beds/lagoons
where marine life causes limestone deposits, later buried. This
process may be involved in initiating the movement of tectonic
plates with consequent removal of salts to land masses.
One example of the complex processes which
Lovelock sees as
maintaining conditions suitable for life is that involving the
Coccolithophores. These and other ocean algae are key agents in the
great cycle of carbon from its introduction to the atmosphere by
volcanoes, the weathering of limestone rocks accelerated by
life in the soil (which also draws down carbon from the air), the
combination of these as calcium bicarbonate which, washed into the
oceans, is used by algae to form shells which eventually fall to the
sea floor to be buried, so locking away the excessive carbon
dioxide. Additionally the Coccolithophores release a gas (DMS) which
is important in forming the condensation nuclei around which clouds
form. Increased cloud cover reflects sunlight, so controlling
surface temperature. There is some evidence that concentrations of
ocean algal blooms are increasing. This may be a Gaian response
to the present global warming.
The Gaia Theory has been attacked, particularly by
thinkers W. Ford Doolittle and Richard Dawkins. They challenge
Lovelock to show how organisms could produce concerted action,
arguing that there is no way that natural selection could lead to
altruism on a global scale. This, they argue, would require
foresight and planning on the part of the organisms, such ability
would need to be built into their genetic structure. They find it
impossible to see how the feedback loops which Lovelock says
stabilize the Gaian system could have evolved. They argue that, as
Gaia can’t reproduce herself, she cannot be alive in any meaningful
sense. They also claim that the theory is not scientific because it
is impossible to test it by controlled experiment. Lovelock offered
The Daisyworld model as mathematical evidence to refute most of
The Daisyworld model
Daisyworld is a computer model of a hypothetical planet with
characteristics similar to Earth including a rising input of solar
heat. On its surface are, evenly scattered, the seeds of only two
species: black daisies and white daisies. Early in the life of the
planet conditions are cool; only at the equator is it warm enough
for seeds to germinate and there the black daisies have the
advantage as they more readily absorb what heat there is. As solar
input rises the black daisies spread away from the equator and white
ones gain a hold in the increasing warmth. When heat increases to
the point where black daisies are overheated they can survive only
near the poles, the rest of the surface being covered by the highly
reflective white daisies. Surface temperature is initially increased
by the absorptive black daisies, then stabilized for a long period
by increasing concentrations of the heat reflecting whites.
Eventually the increasing solar heat is too much for even the
whites; these die and the planet becomes too hot for life.
Lovelock points out that, in this model, the effects beneficial to
life are obtained by means of natural selection only - there is no
need for purpose, altruism, teleology or anything beyond normal
genetic process. In subsequent models grey daisies, herbivores and
their predators have been added. These have proved more stable than
other models that do not take environmental feedback into account.
Gaian theory inevitably raises the issues of "teleology": whether
non-human beings, ecosystems or genetic and evolutionary processes
can have any sort of "purpose" and what that means.
that his theory demands responsiveness in the system(s) but not
awareness, foresight or intention. The action of organisms is always
automatic but natural selection "chooses" those that are fitted for
the conditions - as in Daisyworld. Questions, however, remain. Why,
for instance, should the needs of coccolithophores be exactly what
will serve to take CO2[NGC1] (excessive for other planetary life)
out of the atmosphere? If the system is in control, does this gives
ontological status to the system itself? Is the whole system somehow
able to value the continuance of "life"?
In Lovelock’s view humanity is peripheral, though dangerous, to the
life systems of the planet. Our anthropocentric concern is to
preserve the earth as we want it. Lovelock believes that ideas of
stewardship of the planet are absurd and dangerous "hubris": "We’ll
never know enough…….. The answer is ’hands off". The large plants
and animals are the icing on the cake; the basis of life - what
matters for a living planet - is the microbiological.
Micro-organisms drive the system and we cannot influence them. We
are probably incapable of destroying life on Earth. We can refrain
from doing what we see is damaging but little more. This raises
profound questions about responsible action for individual humans
and social groups. Is value related to the continuance of life in
general, to the experience of humans or of sentient animals? Why
does it matter if species are destroyed?
Gaian thinking suggests an alternative to the view that the world is
mechanistic, best understood by reducing everything to "parts", that
life has come about by chance operation of the laws of physics and
chemistry, that evolution is a matter of ruthless competition and
that the natural world is there to be exploited. The new view shows
the living world as interconnected, in some sense meaningful. What
follows from instituting a new metaphor for the old "world as
machine" one? David Abrahm’s paper in "Gaia in Action" (see reading
list at bottom) suggests that the change to an organic metaphor removes the
assumption of an external "maker" who is in some way like a human
creator of machines. This undermines our assumption that we can
treat nature as a machine and allows recovery of our sense of being
encompassed by and immersed in the world as participants. In his
introduction to the same book, Peter Bunyard suggests that
world has more to do with co-operation than competition, with
integration of organisms and environment rather than struggle and
competition. This provides, he says, fertile metaphors for
community. Lancaster’s own Kate Rawles follows this with a paper
which asks what ethics follow from the Gaian view.
Does it imply
that ethical concern extends beyond humans to other sentient beings?
To the planet?
What sort of obligations and
responsibilities could this meaningfully involve?
Does Gaia theory
suggest that there are specifically environmental goals and values?
Does it tell us how we ought to act?
Does it depose humans from
their assumed position at the "apex of evolution" and, if so, what
There are further implications. The
Gaian view may make it possible
for humans to see themselves as significant (because conscious and
self-reflexive) parts of a symphonic interaction. Could the whole
earth as a single life preserving system command our respect, awe,
even reverence? Could an understanding of Gaia become the focus for
attitudes we have called "religious", thus influencing change in
human impact on the planetary process? Lovelock has written
Gaia is a religious as well as a scientific concept, and in both
spheres it is manageable… God and Gaia,
theology and science, even
physics and biology are not separate but a single way of thought".
("The Ages of Gaia", pp. 206, 212. See reading list
Bunyard, Peter (ed.),
"Gaia in Action: Science of the Living Earth", Floris Books, Edinburgh, 1996. The most recent anthology of Gaian
writing including contributions by Lovelock, Lynn Margulis, Brian
Goodwin, Elisabet Sartouris and Kate Rawles.
Lovelock, J. E.
"Gaia: a New Look at Life on Earth", OUP, Oxford, 1979. New edition
with updated Preface, 1987.
"The Ages of Gaia: A Biography of our Living Earth", OUP, Oxford,
1988. New edition, 1996.
"Gaia: The Practical Science of Planetary Medicine", Gaia Books
Ltd., London, 1991. (In USA: "Healing Gaia: Practical Medicine for
the Planet", Harmony, New York. 1991.)
Margulis, Lynn, & Sagan, Dorian,
"What is Life", Simon & Schuster,
New York, 1995.
The computer "game" Sim Earth (Maxis Inc.) provides entertaining
opportunities to play with the Daisyworld concept and more complex