Mass Extinction Event On the Horizon? (broadcast Friday, August 15th, 2008)

Carcasses of Southern Yellow-legged Frogs in Sixty Lake Basin in Sierra Nevada, California. The frogs died of chytridiomycosis, an amphibian disease caused by a particularly virulent fungus. Vance Vredenburg / UC Berkeley

Scientists studying many different parts of the planet's ecosystems are warning that Earth may be on the verge of a sixth major mass extinction event. In a series of papers published this week in the Proceedings of the National Academy of Sciences, researchers examining biodiversity around the globe paint a gloomy picture for the planet's species. Warning signs include recent mass die-offs of amphibians and declining fisheries.

Over the course of the Earth's history, there have been at least five major extinction events -- the End Ordovician, Late Devonian, End Permian, End Triassic, and End Cretaceous. But are we facing a sixth major extinction period -- and is there anything that can be done about it? In this segment, Ira talks with biologist Paul Ehrlich about what is driving biodiversity loss and what can be done to reverse the trend. Teachers, find more information about using Science Friday as a classroom resource in the Kids' Connection.