The Gaia Hypothesis: Is the Earth Alive?

Examining the Gaia hypothesis proposing that the earth is alive and behaves like a living system.

| May/June 1986

Earth alive theory

Lovelock is saying that the evolution of life and the evolution of the planet have not been separate phenomena but one single, tightly coupled process.


More than one astronaut looking back at our planet has been awed into concluding that this blue and green globe is, in fact, a living being. Of course, many native peoples the world over have always believed (and functioned on the premise) that the earth is alive.

And now contemporary scientists are talking more and more about the Gaia hypothesis: the proposition that, in some ways, the planet does behave like a living system. (Gaia pronounced "Guy-uh" — was the Greek goddess of the earth.)

"What's that?" you say. "Scientists are saying the earth is alive?" Well, the honest answer to that is "No, but  . . ." And the "but" becomes quite fascinating.

The Gaia Hypothesis: Is the Earth Alive?

British scientist James Lovelock, the person most responsible for the Gaia hypothesis, was working for NASA when he first reached his living system insight questioning is the earth alive? Surprisingly, though, at the time he was creating tests to detect life on Mars!

Lovelock had taken the approach that, rather than have satellites take minute soil tests on the red planet (using what he described as "glorified flea detectors"), scientists should look at Mars' atmosphere to see if it has any concentrations of gases that could exist only if they were maintained by living organisms. To test that idea, Lovelock looked at the atmosphere of our own planet. Sure enough, earth's air contains large quantities of highly reactive gases — such as oxygen and methane — that naturally break down into other compounds. "If chemical thermodynamics alone mattered," he wrote, "almost all the oxygen and most of the nitrogen in the atmosphere ought to have ended up in the sea combined as nitrate ion."

This simple discovery later developed into one of Lovelock's original arguments for Gaia: Something is maintaining numerous reactive gases in our atmosphere in an equilibrium steady state. (Mars, by the way, flunked the "active atmosphere" test.)

mother earth news fair


More than 150 workshops, great deals from more than 200 exhibitors, off-stage demos, inspirational keynotes, and great food!