New book suggests Earth perhaps not such a benevolent mother...( In the past 50 years it has become ...)

In the past 50 years it has become commonplace to think of Earth as a nurturing place, straining mightily to maintain equilibrium so that life might continue and flourish.

The Gaia hypothesis, named for the ancient Greek goddess of Earth, even put forth the idea that our planet behaves as a kind of giant organism, with its complex systems finely tuned to compensate when one system gets out of kilter.

But actually it is the Gaia view that is out of kilter, says Peter Ward, a University of Washington paleontologist who has looked closely at conditions that existed during numerous mass extinction events in Earth's history.

In a new book, he suggests the planet ultimately is inhospitable to life, and that life itself might be the primary reason. Rather than Gaia, he invokes the darker Medea from Greek mythology.

"The Medea hypothesis says life is already shutting down Earth as a habitable planet. Not just the diversity of life, but the actual biomass," Ward said. "Life keeps evolving, and there are unintended, often negative, consequences."

"The Medea Hypothesis: Is Life on Earth Ultimately Self-Destructive?" was published in April by Princeton University Press. In the 208-page book, Ward argues that humans have to use engineering to manage their environment or face potential extinction if the Earth is left to manage itself.

"The engineering I'm talking about is not girders and sky shields. It's engineering microbes to take over food production and energy production," he said.

Microbes have undergone evolution, a sort of natural engineering, throughout Earth's history, he said, and humans have the ability to guide such changes to clean the environment, for example, or regulate carbon dioxide in the atmosphere.

Like Gaia, Medea is a mythological character, though she is decidedly much darker in nature. Medea was married to Jason at the time he pursued the Golden Fleece but, according t
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