now a theory that purports Earth’s life as its means of self-regulation.
It is called the Gaia hypothesis, and it was purveyed first by a
man named James Lovelock in the early 1970’s. The main idea
is that all organic and inorganic components of the earth’s
biosphere regulate its temperature, chemical makeup, nutrient cycling,
and atmospheric pressure—everything essential to life’s
continued existence. It claims the earth as being one organism,
and all the interactions of all the organic and inorganic elements
of the biosphere are designed to maintain a balance of the conditions
that best support life.
Life sustains the atmospheric and surface environment,
thus sustaining itself.
And it has been for about 3 billion years! The single
largest environmental pollution event in the history of the earth
occurred approximately 2 billion years ago when a partnership of
two particular kinds of bacteria was forged. Environmentally, oxygen
was present in inorganic forms as the product of the many reactions
taking place on the incredibly volatile young planet. The aforementioned
chimerical symbionts used oxygen to produce cellular energy
through a series of reactions at a rate eighteen times faster than
their contemporaries. This, in turn, encouraged the oxygen-producers
to succeed, as the waste from one set of reactions became the food
for another and so on. Many of the then-present species/types of
bacteria evolved out.
So began the environmental shift from virtually anoxic
to significantly oxygenated, and the literal growth of the inhabitants
of the planet; two bacterial cells together are bigger than one
alone. Countless interactions had been attempted and failed to that
point, but this particular relationship stuck. Call it pollution,
as it resulted in a total shift of environmental makeup. Call it
whatever you want, but we can obviously see that an oxygenated environment
(that Gaia has sustained since its creation) makes the most evolutionary
sense for us here on the planet. There are 2 billion years of evidence
that support this idea.
To further simplify, we can use a fantastic model
created by Lovelock and his colleagues to illustrate a planet’s
Gaian regulation of only one variable, temperature. Imagine a planet
that is covered in nothing but black and white daisies. The black
ones absorb heat and warm the surface of this Daisyworld whereas
the white ones reflect heat and lower the surface temperature. The
white plants grow better at higher temperatures, say, 20 degrees
Celsius, where the black ones grow best at 5-10 degrees Celsius.
Neither can grow beyond 40 degrees Celsius. Daisyworld is located
as far from its sun as is the Earth, and like our sun, it increases
its luminosity and hence temperature over time.
Before any growth of daisies, the temperature is close
to 5 degrees Celsius, a condition that favors the black daisies.
As they grow and cover vast areas of the planet’s surface,
the surface temperature of those areas increase. Eventually, the
conditions of warmed areas of planetary surface favor the white
daisies, which start to grow as well. The two species would eventually
find a balance where they could be equally successful over a range
of solar luminosity, regulating the temperature of the surface of
the planet, but maintaining a set of conditions that was favorable
to their continued existence. This is a terribly oversimplified
illustration of Gaian theory, but it does a good job expressing
The oxygen concentration of our atmosphere has changed
very little over the last 2 billion years, which coincides with
the fossil record to show when life proliferated on our planet.
Currently our planet’s atmosphere is made up of 21 percent
oxygen gas. If it were to increase to 25 percent, huge fires would
ignite with even the smallest flame. If it were to decrease to 13
percent fires would not start at all. Three billion years ago, our
sun was 30 percent less bright. Though the conditions in our little
corner of space have changed significantly over the last 2 billion
years, the chemical makeup of earth’s atmosphere has not.
There is a huge amount of support of the Gaia hypothesis from high-level
scientists the world over, and though its scope is, in my opinion,
beyond being proven, I find it to be an incredibly refreshing take
on the nature of things on our beloved planet.
The idea that the planet acts in its own best interest
can and should lend perspective to our place here. Gaia includes
us all; it does not bear any of the same prejudices that we do.
Gaia will find a way to regulate itself, with many forms of wonderful
life. What the hypothesis does, philosophically speaking, is give
meaning to every breeze and blade of grass, where most current dogma
places importance on faith and things which cannot be grasped and
therefore questioned. I, think it is time for us collectively to
stop placing our very real faith in things intangible, and instead
look at what actual beauty does surround and, yes, include us all.
Take a nice deep breath and thank Gaia you’re alive.
1. Margulis, Lynn, and Olendzenski,
Lorraine, editors. Environmental Evolution. Effects of the Origin
and Evolution of Life on Planet Earth. Cambridge, MA: The MIT
Press, 1992, pp. 295-324.
2. Margulis, Lynn, and Sagan Dorian. What is Life? New
York, NY: Simon and Scheuster, 1995, pp. 90-115.