While Erwin’s argument that a mass extinction is not yet under way might seem to get humanity off the hook—an invitation to plunder the earth further, since it can seemingly take the beating (the planet has certainly seen worse)—it’s actually a subtler and possibly far scarier argument. This is where the ecosystem’s nonlinear responses, or tipping points, come in. Inching up to mass extinction might be a little like inching up to the event horizon of a black hole—once you go over a certain line, a line that perhaps doesn’t even appear all that remarkable, all is lost. “So,” I said, “it might
...more
