Are we tru­ly in the midst of a human-caused sixth mass extinc­tion, an era of “bio­log­i­cal anni­hi­la­tion”? Many sci­en­tists and pop­u­lar sci­ence writ­ers say yes, using terms like “Holocene” or “Anthro­pocene” to describe what fol­lows the Ordovi­cian, Devon­ian, Per­mi­an, Tri­as­sic, and Cre­ta­ceous peri­ods. Peter Bran­nen, the author of extinc­tion his­to­ry The Ends of the Earth has found at least one sci­en­tist who thinks the con­cept is “junk.” But Bran­nen quotes some alarm­ing sta­tis­tics. Chill­ing, even. “Until very recent­ly,” he writes, “all ver­te­brate life on the plan­et was wildlife. But astound­ing­ly, today wildlife accounts for only 3 per­cent of Earth’s land ani­mals; human beings, our live­stock, and our pets take up the remain­ing 97 per­cent of the bio­mass… almost half of the Earth’s land has been con­vert­ed into farm­land.” This state of affairs does not bode well for the mil­lions of remain­ing species get­ting edged out of their envi­ron­ments by agribusi­ness and cli­mate change. We learn from extinc­tions past that the plan­et rebounds after unimag­in­able cat­a­stro­phe. Life real­ly does go on, though it may take mil­lions of …