This is an excerpt from a recent chat on humanity's growth spurt and the #Anthropocene age of Earth history it's creating -- between David Biello, the TED curator of science and author of "Unnatural World," and Andy Revkin, who's written extensively on the Anthropocene and is moving from the New York Times and Pace University to ProPublica.org. A transcript and the rest of the talk are here thanks to Heleo.com: heleo.com/conversation-david-biello-and-andrew-revkin-on-why-we-should-stay-hopeful-in-the-face-of-climate-change/11818/