This week in the Planet Earth Podcast - Richard Hollingham talks to one of the scientists behind the discovery of the ozone hole to find why it's still there; how research on starlings on an island famous for its sweaters could help bird conservationists; and why forest fires in North America affect people thousands of miles away in Europe.

• The Ozone Hole, Starlings in Fair Isle, Forest Fires - Naked Scientists Science Podcasts and Science Radio Shows
• Ozone Depletion and Behavioural Change - Planet Earth Online - Interviews
• Rainfall, Cloud Dwelling Bacteria and The Ozone Hole - Naked Scientists Science Podcasts and Science Radio Shows
• Volcanic pollution, the Ozone Hole and the Greenhouse Effect - The Atmosphere Show - Naked Scientists Science Podcasts and Science Radio Shows
• What Makes Mucus Green? - Podcasts
• Pushing Back the Pain Barrier - Podcasts