Imagining Gaia, the Earth, as 'one great, living organism'

The World - Living on Earth

Written By: Steve Curwood

Published: May 20th, 2021

James Lovelock's hypothesis could unlock a whole-systems approach to protecting the amazing life forms on Earth.

Over 50 years ago, scientist James Lovelock hit upon the idea that Earth is a complex, self-regulating organism. At the suggestion of a friend, novelist William Golding, he called his idea the Gaia hypothesis, after the Greek goddess who symbolizes Earth.

Simply put, the Gaia hypothesis says that Earth is a living system and uses similar mechanisms that living creatures use to stay alive, by constantly regulating temperature, chemical and physical inputs and outputs and adaptation through evolution.

Lovelock, who turned 101 in 2021, came up with his idea in the 1960s, when NASA asked him to see if his inventions in chemical analysis could detect life on other planets by looking at their atmospheres.

Venus, our nearest neighbor at 25 million miles closer to the Sun than Earth, is literally a hot mess, with steady surface temperatures of nearly 900 degrees Fahrenheit and an atmosphere of mostly carbon dioxide laced with bits of sulfur droplets — not hospitable for life forms we know.

Mars, 100 million miles further from the Sun than Earth, is a bit less hostile to life, with days of searing heat and nights of deep cold. It also has an atmosphere overwhelmingly made up of carbon dioxide, with just tiny traces of oxygen.

Lovelock’s insight came when he realized that the bigger question was not, "Is there life on those other planets?" but rather, "Why is there life here on Earth?"

Like Venus and Mars, Earth has strong volcanos that, over time, have spewed out huge amounts of carbon dioxide. These volcanos should have created a hothouse or a desert on Earth. But something has kept carbon dioxide levels in a sweet spot: just four hundredths of a percent of the Earth’s atmosphere, enough to keep it warm, but not too warm, for life, while the oxygen needed for animals is in great abundance — and that something is life itself.

About a billion years after Earth was formed, photosynthesis evolved. Photosynthesis is how plants, algae and other organisms convert sunlight into chemical energy and break down CO2 into its elements, carbon and oxygen. Over millions of years, plants and algae sequestered in their cells all that carbon from volcanos, and when buried in the ground or under the sea, some of it eventually became coal and oil.

Four times in Earth’s geologic history, giant eruptions of volcanoes belched out so much CO2 they set off mass extinctions. A separate mass extinction was linked to an asteroid strike that likely shut down a lot of Earth’s photosynthesis and allowed CO2 levels to rise.

After each of these cataclysmic events, Earth had to start sequestering carbon again, as life evolved to adapt to new conditions. So, when we drill and dig up fossil fuels today, we are upsetting a balance the Earth works hard to keep. But if we keep those fossil fuels in the ground, we help support the living planet.

Many scientists have helped advance the Gaia hypothesis — now known as Gaia theory — over time. One of the most public voices is Stephan Harding, a former student of James Lovelock. Harding is now a deep ecology research fellow at Schumacher College in England.

In sum, he says, every living plant and animal on Earth interacts with nonliving rocks, atmosphere and water to make the planet an independent, living organism.

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