As opposed to the Gaia Hypothesis.

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, a paleontologist at the University of Washington and a scholar of the earth's great extinctions, calls his model the Medea Hypothesis, after the mythological Greek sorceress who killed her own children. The name makes clear Ward's ambition: To challenge and eventually replace the Gaia Hypothesis, the well-known 1970s scientific model that posits that every living thing on earth is part of a gargantuan, self-regulating super-organism.

Ward holds the Gaia Hypothesis, and the thinking behind it, responsible for encouraging a set of fairy-tale assumptions about the earth, and he'd like his new book, due out this spring, to help puncture them. He hopes not only to shake the philosophical underpinnings of environmentalism, but to reshape our understanding of our relationship with nature, and of life's ultimate sustainability on this planet and beyond.

It's an intentional exaggeration justified, at least in Ward's mind, by the equally nonsensical Gaia mentality that has insinuated itself into the popular mind and resulted in crack pot policies. His science is disputed as well. The paleontology cited by Ward is unsettled as there are other theories for the extinction events.

Ward cheerfully concedes that he may be proven at least partly wrong. . .

At the very least, Ward hopes to shape the image of the earth in the public imagination, and by extension in public policy. Beneath much environmental regulation lies the basically Gaian belief that, when faced with a brewing global problem like climate change, our best response should be to try as much as possible to take ourselves out of the equation, to reduce our carbon emissions to the point where we're no longer a factor in the feedback loops. Trying instead to manage something as hopelessly complex as the climate is seen as an act of Frankensteinian hubris.

Ward, however, argues that this way of seeing things only makes sense if one assumes that the earth will, once righted, inevitably return to the set of conditions most suitable for our continued survival. History, he argues, suggests it very well may not. Faced with a planet where life is almost guaranteed to wipe itself out - and take us with it - he is urging us to be active, and occasionally intrusive, guardians.

I have some sympathy for the general idea that the earth is anything but a benign cradle for human kind. If we are to endure as a species it will have to be done with wit and energy, and if we are to remain civilized it will take great wit and great energy since the planet has seldom been as cozy as it has been for the past few millenia.

"The longevity of the biosphere can only be sustained through large-scale geoengineering," Ward argues. Without our firm hand, he believes, "the earth will go to hell in a handbasket," just as it has again and again in the past.

His claims are irrefutable in the long run, but it is less clear that there is an immediate need for a "firm hand", and quite certain that we do not now have the knowledge to do such management on a large scale. It makes sense to begin developing more mature views than the Gaia nonsense, and there is immediate practical benefit to opposing most of the policies spawned by such nonsense.

One benefit of a more accurate view of the earth's life history might be greater recognition of the local effects of humans. Much of what is commonly thought of as pristine natural wilderness is human created or at least heavily altered by humans. The significance is that to maintain such "wilderness" requires continued human management rather than the neglect advocated by Gaians. The only way that the Gaia meme works is if humans have an active role, and the only way that the system continues to function within our comfort zone is if we make it so. Easier said than done, but it must be said.