and then daniel beaty, "transforming pain to power," putting his difficult childhood into perspective. he is touring a new play he wrote about paul robeson titled "the tallest tree in the forest." we're glad you joined us. those conversations coming up right now. ♪ ♪ >> and by contributions to your pbs station from viewers like you. thank you. ♪ ♪ tavis: there have been five epics where catastrophic events have wiped out life on earth. the fifth extinction was caused by an asteroid wiped out the dinosaurs. elizabeth kolbert who covers the environment for "the new yorker" says we're living in the middle of another mass extinction, this one, though, caused by human activity. her tome is called "the sixth extinction," an unnatural istory and the result of years of research. elizabeth, thanks for being on the program. >> thanks for having me. tavis: starting in an unlikely place which is this notion of why there is so much debate. you have scientists, you have researchers, you have best selling texts about the reality of what we're enduring today and yet on capitol hill and beyond because