 In The Life and Death of Planet Earth,
authors Peter Ward and David Brownlee trace the entire history of our
planet, from its formation 4.5 billion years ago (8 billion years after
the Big Bang) to its inevitable demise 7.5 billion years from now, when
our sun expands just before its death and its heat incinerates our
entire galaxy. They argue that while short-term weather is highly
unpredictable, longer-term phenomena are less complex and hence very
predictable. We are, they assure us, half way through the brief
one-billion-year period during which our planet can support any plant
or animal life, after which it will revert to a hellishly hot planet
capable of supporting only the bacteria from which all complex life
evolved.
The charts at right show, from top to bottom, (a) major events in the
full 12 billion year life of Earth, (b) magnified 10 times, the 1
billion year period that supports complex life forms and its five known
major extinction events (the last of which extinguished the dinosaurs),
and (c) magnified 1000 times, our species' brief stint on the planet.
The red line shows the average Earth surface temperature, to the best
of our knowledge, and the pale green band is the temperate range that
can support plant and animal life. All of the blips to the left
represent ice ages. The ones that go all the way to -70C are 'snowball
Earth' periods when the planet was completely covered in ice miles
thick. The smaller ones are partial glaciations, which mysteriously
ceased about 250 million years ago and then started up again about 2.5
million years ago and are expected to continue, every 100,000 years or
so, for another 2 to 10 million years, after which the planet will
again inexorably heat up to unbearable levels. We are on the cusp of
another ice age, perhaps in 5,000 years, and the only thing scientists
can't agree upon is whether our human-made destruction of the ozone layer
will delay it a few thousand years, or accelerate it. They can agree
that global warming will bring cataclysmic change, violent and unstable
weather, and huge changes to our planet's topography.
Ward and Brownlee claim not to believe fully in Gaia theory, because
the behaviour of our planet does not fully meet the scientific
conditions necessary to qualify it as an 'organism' (e.g. it does not
reproduce). But as I read the book I began to understand why all life
on Earth does act, usually, in harmony and cooperation in collective
interest, just as the organs of our bodies do. The
task of regulating Earth's temperature is such a massive and
constantly-challenging job that it takes all of us, working together,
to succeed at it. In Darwinian terms, individual life-forms
competing strictly in their own self-interest will continually fail to
survive the sharp temperature changes their selfishness allows. Only a
life model with global awareness, respect and cooperation can sustain any of us
in this temperature-fragile environment. Plant and animal life evolved
a half billion years ago as a 'conscious' mechanism to perpetuate
itself by regulating the temperature of its host planet. And it has
done that awesome task remarkably well: Despite extinction events like
meteor impacts, massive volcanic eruptions and ice ages, complex life
has endured on our planet and re-regulated the planet's temperature
remarkably quickly for half a billion years, and may be able to do so
for another half a billion if some arrogant and selfish species like
humanity doesn't mess it up.
In the blink of an eye since humans emerged on the planet, and more
specifically in the even briefer period since we built civilization, we
have extinguished more species of life on the planet and transformed the
life-sustaining biosphere more severely and quickly than any of the
previously recorded extinction events. Civilization detached humanity from
the global consciousness that regulated Earth's temperature, and
allowed us to pursue a selfish, reckless, and environmentally
destructive course. Our biosphere -- the respiration of all plants and
animals on the planet, the movement of the ocean currents and
atmosphere, regulates Earth's surface temperature astonishingly well,
and adapts to or quickly recuperates from external events and anomalies
(like movement of the continental plates, meteor impacts, large-scale
volcanic activity, changes in our orbit around the sun, the tilt and
wobble of the planet's axis, and our planet's periodic passage through
vast amounts of cosmic debris and dust). But our burning of fossil
fuels, pollution of the air and water, and diminishing of the planet's
forest cover and desertification of much of the planet's surface are
throwing a monkey-wrench into this finely-tuned mechanism of
regulation.
Even if we are somehow able to regain our global consciousness and work
with the rest of Gaia to regulate Earth's temperature in all our
interests, we are still only a half billion years from the time when
this self-regulation mechanism will be inadequate to cope with the
sun's ever-growing heat and the continuous depletion of carbon dioxide.
By that time all plant and animal life on the planet will die off, and
our blue, green and occasionally white planet will turn permanently
brown and red, a twin of Mars. And then the heat will evaporate the
oceans bringing the end of even microbial life, so that by the time our
galaxy collides in 3.2 billion years with Andromeda the planet will be
virtually lifeless.
So we are very much like an organ in the human body acting up so
irresponsibly that we are putting the whole body at risk. The analogy
is startling, as the authors point out:
You are made of more cells than
there are stars in the Milky Way galaxy, and each cell is a miniature
city with its own highways, factories, waste-processing plants, and a
coil of DNA recording the genetic instructions necessary to make a copy
of you. The cells in turn have combined to make a complex organism that
can move, eat, breathe, reproduce, repair itself, think and dream. Yet
as astonishing as our biology is, we are also mortal, forever in peril
of disease, puncture, and the inevitable dissolution caused by wear and
tear of time. Our home planet is similarly complex and similarly
marvelous.
How arrogant, how foolish we are, to believe that the world revolves
around us, that it is here for our benefit! What will it take for us to
rediscover the wisdom that all other life instinctively knows, that our
purpose is to do our small part to help regulate the temperature and
well-being of the whole organism of which we are inextricably a part,
this astonishingly rare and vibrant and wondrous blue-green ball, for
the benefit of all life, for the brief period we have the privilege to
be alive as a part of its awesome and finite history?
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MADE IN CANADA
trust your
instincts 
