Now, as McKibben observes, we are blasting Earth's inhabitants with ever-increasing levels of ultraviolet light as our industrial gases consume stratospheric ozone. And while the rising curve of species extinctions may be "local," they're hardly "natural." There was no magic moment; we are remaking the Earth by degrees.
That makes what is happening no less tragic for those of us who value wildness for its own sake, not for what value it confers upon mankind. I, for one, cannot wish upon either my children or the rest of Earth's biota a tame planet, a human-managed planet, be it monstrous or--however unlikely--benign. McKibben is a biocentrist, and so am I. We are not interested in the utility of a particular species, or free-flowing river, or ecosystem, to mankind. They have intrinsic value, more value--to me--than another human body, or a billion of them.
Human happiness, and certainly human fecundity, are not as important as a wild and healthy planet. I know social scientists who remind me that people are part of nature, but it isn't true. Somewhere along the line--at about a billion years ago, maybe half that--we quit the contract and became a cancer. We have become a plague upon ourselves and upon the Earth.