STANFORD – There is no doubt that Earth is undergoing the sixth mass extinction in its history – the first since the cataclysm that wiped out the dinosaurs some 65 million years ago. According to one recent study, species are going extinct between ten and several thousand times faster than they did during stable periods in the planet’s history, and populations within species are vanishing hundreds or thousands of times faster than that. By one estimate, Earth has lost half of its wildlife during the past 40 years. There is also no doubt about the cause: We are it.
We are in the process of killing off our only known companions in the universe, many of them beautiful and all of them intricate and interesting. This is a tragedy, even for those who may not care about the loss of wildlife. The species that are so rapidly disappearing provide human beings with indispensable ecosystem services: regulating the climate, maintaining soil fertility, pollinating crops and defending them from pests, filtering fresh water, and supplying food.