THE AGES OF GAIA
James Lovelock (1988)
The Gaia Hypothesis:
First proposed 15 yrs ago by British scientist James
Lovelock and named after Gaia, the Greek Earth goddess, it proposes the
revolutionary principle that the Earth is alive. According to the Gaia Hypothesis, life shapes and controls the
environment, rather than the other way around.
The two have evolved together and every individual life form, from
microbe to man, is involved - simply by its own life processes - in homeostatic
systems that have evolved to operate on a global scale.
In 1910, Vernadsky, a Ukrainian scientist, described
the biosphere as "the envelope of life, i.e. the area of living matter
(biosphere) can be regarded as the area of the earth's crust occupied by
transformers which convert cosmic radiations into effective terrestrial energy;
electrical, chemical, mechanical, thermal, etc."
The Gaia hypothesis supposes that the atmosphere, the
oceans, the climate, and the crust of Earth are all regulated at a state
comfortable for life because of the behaviour of living organisms. Specifically, it states that the
temperature, oxidation rate, acidity, and certain aspects of the rocks and
waters are at any time kept constant, and that this homeostasis is maintained
by active feedback processes operated automatically and unconsciously by the
biota. Solar energy sustains
comfortable conditions for life. The
conditions are only constant in the short term and evolve in synchrony with the
changing needs of the biota as it evolves.
Life and its environment are so closely coupled that evolution itself is
Gaia, not the organisms or the environment taken separately.
Earth atmosphere comprises: CO2 - 0.03%
Nitrogen - 78.0%
Argon
- 1.0%
Methane
- (1.7ppm)
Lovelock makes reference to the computer models of
Daisyworld showing the solar radiation reflective/absorptive power of
foliage/water crystals/ice caps in cloud formations to smooth out the earth's mean
temperature, notwithstanding an increasing solar intensity of 30% during the
3.6 billion yrs since micro life commenced – (total age of Earth being 4.5
billion years).
Reference
is made to evolution not being a gradual process, but rather greatly influenced
by periodic catastrophes (e.g. approx. 30 strikes by planetoids, up to 10 mi in
diameter and travelling 60 x sound speed, releasing 1000 x energy of all
present nuclear weapon stocks, creating 200 mi craters and destroying up to 90%
of all living organisms).
The first life forms started from the molecular
chemical equivalent of eddies and whirlpools, with single cells evolving over
time into photosynthesizers which could tap the sun's energy to convert their
own food from the available minerals. In time, cyanobacteria became able to
break the strong bonds binding oxygen to hydrogen (creating 'free' oxygen) and
oxygen to carbon (creating add'l free oxygen plus carbon which in the form of
calcium became skeleton material). Bacteria used carbon dioxide as food, and
discharged organic matter and oxygen (much as the photosynthesis of plant life
today). The oxygen initially was used
in converting (oxidizing) minerals such as iron and sulphur into usable
elements, later animal life evolved which could use the oxygen and thereby
complete the gas cycle.
Since the beginning of Gaia’s cyclic self-sustaining
system, the oceans have maintained a fairly constant salinity, called 0.6 molar
(about 4% salt by weight). The salinity of the blood of whales, humans, mice
and most fish, whether dwelling in the ocean or in fresh water, is identical,
approx. 0.16 molar (1% salt:water by weight).
In a well vegetated region, the soil contains 10 to 40
times the CO2 content of the atmosphere, since the vegetation pumps
it out of the air (via leaves/grasses), deep into the soil thru the roots,
where it reacts with rock particles to free mineral elements, forming calcium
carbonate and silicic acid, etc. which move with the ground water to the sea
where these minerals are used by marine animals to form their shells and
bones. Over time, sedimented limestone
and silica (from the shells) is deposited onto the sea floor and through plate
tectonics becomes the stuff of mountains which in time weather down and again
free the carbon dioxide from its "sink".
Acid rain and smog, while dangerous to local ecology
and maybe fatal to humans in the end, would not bring Gaia itself to her knees
on the long term.
Ozone depletion is not seen as a disaster since the effect
of moderately excess solar radiation can be controlled naturally by variations
in skin pigment, whereas radiation deficiency results in rickets and
osteomalacia. The problem with CFC's
has more to do with greenhouse effect.
The downside effects of nuclear energy are acceptable
bearing in mind it is non-polluting, compared to fossil fuels.
Gaia, the Living Earth, will endure thru its own
systems – ridding itself of humans and other life forms, if necessary, in order
to survive.
In ancient times, belief in a living
Earth and in a living cosmos was the same thing. Heaven and Earth were close and part of the same body. As time passed and awareness grew of the
vast distances of space and time through such inventions as the telescope, the
Universe was comprehended and the place of God receded until now it hides
behind the Big Bang, claimed to have started it all. At the same time, as population increased so did the proportion
forced to lead urban lives out of touch with Nature. In the past two centuries we have nearly all become city
dwellers, and seem to have lost interest in the meaning of both God and
Gaia. As the theologian Keith Ward
wrote in December 1984:
"It is not that people know what God is, and have
decided to reject Him. It seems that very
few people even know what the orthodox traditional idea of God shared by
Judaism, Islam and Christianity, is.
They have not the slightest idea what is meant by the word God. It just has no sense or possible place in
their lives. Instead they either invent
some vague idea of a cosmic force with no practical implications at all; or
they appeal to some half-forgotten picture of a bearded super-person constantly
interfering with the mechanistic laws of Nature."
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