We welcome Peter Brannen to the program for the final installment of our two-part interview. Peter is a journalist, and his work has appeared in publications such as The Atlantic, The New York Times, The Washington Post, and Wired.  His book The Ends of the World, about the five major mass extinctions in Earth's history, was published in 2017. Today we’ll conclude our discussion of his latest title, The Story of CO2 is the Story of Everything: How Carbon Dioxide Made Our World, which is published by Ecco.