Saturday, February 28, 2009

The Medea Hypothesis

In this line of thought, the workings of the natural world, honed over billions of years of evolution, have reached a dynamic equilibrium far more elegant - and ultimately durable - than the clumsy attempts humankind makes to alter or improve them.

According to the paleontologist Peter Ward, however, nothing could be further from the truth. In his view, the earth's history makes clear that, left to run its course, life isn't naturally nourishing - it's poisonous. Rather than a supple system of checks and balances, he argues, the natural world is a doomsday device careening from one cataclysm to another. Long before humans came onto the scene, primitive life forms were busily trashing the planet, and on multiple occasions, Ward argues, they came close to rendering it lifeless. Around 3.7 billion years ago, they created a planet-girdling methane smog that threatened to extinguish every living thing; a little over a billion years later they pumped the atmosphere full of poison gas. (That gas, ironically, was oxygen, which later life forms adapted to use as fuel.)

The story of life on earth, in Ward's reckoning, is a long series of suicide attempts. Four of the five major mass extinctions since the rise of animals, Ward says, were caused not by meteor impacts or volcanic eruptions, but by bacteria, and twice, he argues, the planet was transformed into a nearly total ball of ice thanks to the voracious appetites of plants. In other words, it's not just human beings, with our chemical spills, nuclear arsenals, and tailpipe emissions, who are a menace. The main threat to life is life itself.

"Life is toxic," Ward says. "It's life that's causing all the damn problems."

Ward himself believes that the only help for the planet over the long run is management by human beings - whether that means actively adjusting the chemical composition of the atmosphere or using giant satellites to modify the amount of sunlight that reaches us. As Ward sees it, the planet doesn't need our help destroying itself. It will do that automatically. It needs us to save it.
Interesting. Hopefully his new book The Medea Hypothesis will explain these ideas in more depth and have the data to back them up.

This TED Talk he gave was also fascinating, especially the part on hydrogen sulfide.

via Boston Globe

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