Bruce Shapiro's US politics, and the stories told by tree rings

Our regular US political commentator on the Cornell University sexual assault case, the failed execution of Christa Pike, and the dire outlook for the Republicans, four weeks before the midterms.

Valerie Trouet, a paleo-climate scientist, compares tree rings from living trees with historical and archaeological wood to reconstruct climate patterns going back thousands of years. It enables her to look at how climate has influenced wars, empires and natural disasters.

Guests:

Bruce Shapiro, contributing editor with The Nation magazine and Director of the Global Center for Journalism and Trauma

Valerie Trouet, professor in the Laboratory of Tree-Ring Research at the University of Arizona. Book 'Tree Story: The History of the World Written in Rings'