The dinosaurs were killed during the Fifth Extinction — which scientists suspect was caused by an asteroid. Now, we are living through an epoch that many scientists describe as the Sixth Extinction, and this time, human activity is the culprit. As one scientist put it: We're the asteroid.
Elizabeth Kolbert is the author of the new book The Sixth Extinction. It begins with a history of the "big five" extinctions of the past, and goes on to explain how human behavior is creating a sixth one — including our use of fossil fuels and the effects of climate change.