Mass Extinction: Life at the Brink

Mass extinctions have occurred five times in our world's long history. Narrated by Jeffrey Wright, filmmaker Sarah Holt's PBS/Smithsonian Channel documentary notes these extinctions happen when climate change is "great enough, fast enough." Are we now—as Elizabeth Kolbert asks in her Pulitzer Prize-winning The Sixth Extinction--on the brink of yet another global catastrophe? Mass Extinction examines two previous extinctions (described as "murder mysteries"), the most well-known being the disaster that occurred 65 million years ago, when an asteroid six miles wide hit the Earth near the Yucatán Peninsula at tremendous speed, making an impact that was equivalent to 100 million nuclear bombs. All of the dinosaurs and 50-60 percent of other species died, either from the initial event, or from the ensuing years of acid rain, a compromised ozone layer, and a prolonged period when debris in the atmosphere blocked the Sun, withering plants and starving animals. The "silent witnesses" to this holocaust are found in the rocks, where layers of fossils simply disappeared above a certain boundary. Less well known is the "great dying" of the Permian age, which has been traced to massive volcanic eruptions in what is now known as Siberia (the volcanoes released climate-changing gases and carbon dioxide, making life impossible). Today, in the "age of mammals," humans are the trigger, not just a part of nature but now a "force of nature." Exploding populations, greenhouse gases, ocean acidification, rising sea levels, loss of fish species and coral reefs, all could be signs of an impending doomsday. Scientists believe that the extinction may have already begun and is a "virtual certainty" by the end of this century if action isn't taken now (doing nothing is like "watching the train wreck happen"). A timely wake-up call, this is recommended. Aud: H, C, P. (S. Rees)