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Geo-Engineering Could Save the Planet … and in the Process Sacrifice the World

Having unintentionally warmed the planet, we may have little choice but to intentionally cool it back down. But at what cost?

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That's a concern of James Lovelock, founder of the Gaia theory. Lovelock's new book, The Vanishing Face of Gaia , warns that climate change will wreck civilization. Still, he doesn't think that geo-engineering provides a way out. "If we can't predict what's happening now, how can we predict what's happening in 50 years with some kind of artificial mechanism?" he said to me in a conversation this summer. "It's just moonshine. I think that if we ever take on the task of trying to manage the planet completely -- if we succeed with geo-engineering and we have to run the planet ourselves, doing what the system now does for free -- that we will be on a course for extinction. Because we can never manage it. We haven't learned to live with ourselves yet."

As Lovelock points out, the political and ethical issues are compounded by an epistemological predicament: No one knows how the planet would react. Geo-engineering is unlike any experiment in history in that the subject is the entire globe. On a closed system floating in space, there is no laboratory to test ideas.

"I think geo-engineering is less an ethical question than a methodological question," Martin Bunzl, a philosopher who works closely with Robock, said to me. "Could you answer the risk analysis with enough assurance to deploy at a large scale? The burden of proof is on the proponents to tell us we know enough about how the atmosphere works."

Take the sulfur aerosol proposal. Would stratospheric injection of SO2 rip a hole in the ozone layer? Would it decrease the amount of energy that solar panels capture or, far more troublesome, affect how plants grow? What if it caused a massive drought in Africa? These are the known unknowns. More worrisome are the unknown unknowns -- the consequences we can't even imagine.

"The difference with large-scale geo-engineering is that you can't actually proceed in the normal way that science proceeds: lab to field tests to increased levels of deployment," Bunzl says. "Because you don't have a model that models the whole world system well enough. You can only deploy the whole thing. Or you are trying to make an inference from a small-scale deployment? What will the consequences be at full strength?"

Without a laboratory, any test to see how the atmosphere would react is already a manipulation of the atmosphere. "The problem with sulfur insertion is that you can't get results until you get to a certain strength, and you can't do it without involving the whole atmosphere," Bunzl says. Or, put another way: The only way to investigate the results of tinkering with the sky is to tinker with the sky. The experiment is itself a fait accompli.

The epistemological checkmate means that the very term "geo-engineering" is flawed. Fixing the climate isn't like repairing a bridge or building a skyscraper. The planet is neither an engine nor, in the metaphor used at the beginning of this essay, a supercomputer. It's an enormous living system, intricate beyond the scale of human understanding, our impressive discoveries notwithstanding. A machine has certain parts that work in expected ways: Even when moving, an engine is static. That's why it's reliable. Earth is different: It is, by nature, ceaselessly dynamic. So we can't be certain about the outcome of a given input. Despite all our fancy computer modeling, we will never know for sure how the atmosphere will respond to manipulation.

More than an endeavor of science, geo-engineering would be an act of faith.

Beyond the political and scientific questions lies a much larger moral, even spiritual, problem: Do humans have the right to undertake such a monumental task?

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