"Bill McKibben and Colbert Talk Keystone XL and Climate"
Funny stuff. McKibben knows how to deal with Colbert: Go with the flow (wherever the absurdist host takes it) but stay on your talking points.
The result is Colbert was nicer to McKibben then he is to many such guests. But then Colbert is an optimist: He says with the tar sands, the climate would be half full … of carbon.