The Sixth Extinction

“The Sixth Extinction”

The history of life on Earth alternates long spans of massive slow change punctuated by periods of catastrophic transformation. Normally, change comes so slowly that it remains imperceptible. Species adapt to shifting environments over innumerable generations and go extinct just as gradually. But fast, drastic planet change leaves organisms no time to adapt. For example, Earth changed in an instant 66 million years ago when a six-mile-wide asteroid crashed into the planet near Mexico and wiped out vast amounts of life, including the dinosaurs. This was the most recent of five “mass-extinction events” over the past 500 million years. Today, the planet faces a sixth extinction. Now the agent of destruction is humanity itself.

“The Lost World”

In 1739, a group of soldiers camping near the Ohio River discovered a marsh filled with gigantic bones. The men carried away a 3.5-foot femur, a colossal tusk and teeth weighing10 pounds each. At the time, science had no concept of extinction. Naturalists assumed that the organisms then alive were the only ones that ever lived. They could not classify the unusual bones from Ohio. In 1796, French...