Globe Hackers would like to recommend the following podcast. Please have a listen - it's time well spent.
You will find detailed show notes at Skepticality.
We need to know how to discuss this topic with people who are not convinced that human activity has any major effect on our climate, other species, and the ecology of the Earth. It's of vital importance, or dare I say our future depends on all of us having a very good understanding of these issues.