Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future

More than 200 million years ago, a cataclysmic event known as the Permian extinction destroyed more than 90% of all species and nearly 97% of all living things. Its origins have long been a puzzle for paleontologists, and during the 1990s and the early part of this century a great battle was fought between those who thought that death had come from above and those who thought something more complicated was at work.

Paleontologist Peter D. Ward, fresh from helping prove that an asteroid had ...