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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 to legend, he left her and in revenge she killed their two children.
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http://www.terradaily.com/reports/Earth_Perhaps_Not_Such_A_Benevolent_Mother_After_All_999.html