“A biogeographic scan of Earth’s principal habitat shows that a full representation of its ecosystems and the vast majority of its species can be saved within half the planet’s surface. At one-half and above, life on Earth enters the safe zone. Within half, existing calculations from existing ecosystems indicate that more than 80 percent of the species would be stabilized.”

This passage provides the crux of Wilson’s argument. The extent of destruction caused by human activities is so severe and far-reaching that traditional conservation efforts, which focus only on the most endangered species and habitats, are not enough to slow and eventually halt mass extinctions. Rather, we need an emergency solution that meets the magnitude of the problem: Only by preserving at least 50 percent of Earth’s surface as nature preserves can we hope to save the majority of life and stabilize both the planet’s biosphere and our own future.

“‘The Anthropocene,’ far-distant geologists might say, ‘unfortunately married swift technological progress with the worst of human nature. What a terrible time it was for people, and for the rest of life.’”

Most epochs within the Cenozoic era last at least several million years. The final epoch of this era, recognized by geologists, is the Holocene. It began around 12,000 years ago and is marked by the retreat of glaciers, climate amelioration, and the spread of humans around the world. In a flash of geological time, humans have altered the climate and environment to such an extent, through both technological advances (e.g., factories that result in increased pollution and machinery that can clear an entire section of a rainforest in a matter of weeks) and preferences for short-term decisions over long-range planning, that some researchers argue we should end the Holocene and replace it with a new geological epoch, the Anthropocene.