THE LIVING EARTH 217
conducive to more complex forms
of life. Eventually, the equilibrium
conditions that exist on Earth
today were established.Saving the planet
As Lovelock elaborated on the
theme, the scientific establishment
gradually began to accept the Gaia
hypothesis. In the 1980s, a series
of “Gaia conferences” attracted
scientists from many different
disciplines, willing to explore the
mechanisms involved in regulating
Earth’s environment to achieve
homeostasis. Later, more attention
was devoted to looking at the
implications of the hypothesis
in the face of climate change.
Human activity had been shown
to disturb Gaia’s system, but the
issue was now whether its
regulatory mechanisms could
withstand further pressure—or
whether Earth was facing another
irreversible tipping point.
Environmentalists, who had
been among the first to embrace
Gaia, reacted with dismay to the
theory that the human species may
precipitate a catastrophic change
in Earth’s equilibrium. The rallying
cry of Green activists became
“Save the planet!” but this was at
odds with the fundamental idea of
Gaia. Although the destruction
of natural habitats, the excessive
burning of fossil fuels, the depletion
of biodiversity, and other human-
made threats were likely to have
severe consequences for many
species—including humans—
the planet, according to the Gaia
hypothesis, will survive and find
a new equilibrium. ■Nuclear power stations produce
plentiful “clean” energy, but also toxic
waste. James Lovelock believes Earth
is able to absorb and overcome the
waste’s radioactive effects.An algal feedback loop
In Gaia theory, feedback loops keep Earth in
balance. One example is the effect that sea algae called
coccolithophores have on keeping the planet’s climate in
check. When the algae die, they release a gas, dimethyl
sulphide (DMS), that helps to create clouds.Lots of clouds mean
heat from the Sun
is reflected back
into space.Fewer clouds mean
more heat from the Sun
reaches Earth.Cooler temperatures
mean lower algal
growth and
less DMS gas.Warmer temperatures
mean higher algal growth
and more DMS.More DMS
means
more cloud.Less DMS
means
fewer clouds.US_214-217_Gaia.indd 217 12/11/18 6:25 PM