Ozone threat not solved, scientists say. From Zurich, lead author Dr. William Ball says Earth's ozone shield against harmful radiation continues to weaken - despite an improvement of big ozone holes over the Poles. It's possible our smog is the last protection. But wait. Another study from University of California Berkeley says a weakened ozone shield 251 million years ago drove the mass extinction of forests, and all life that depended on them. Lead author Jeffrey Benca: we underestimate the risk of harm from thinning ozone,& misunderstand the hidden process of mass extinction.
Interviews by Alex Smith
Snatch of music from Dana Pearson
In the Affiliates version, there is a break and re-intro at 27:29 for stations needing to insert station ID or announcements.