Sierra Club Radio - July 6, 2013

This week on Sierra Club Radio:

- Fortune contributing editor Marc Gunther talks with us about his new piece in Sierra magazine on Warren Buffett's coal problem

- Avital Andrews shares green snacking tips for yummy eco-friendly dips and spreads

- Author Tim Gallagher talks with us about his book Imperial Dreams: Tracking the Imperial Woodpecker through the Wild Sierra Madre