What Earth's past can teach us about climate change and our future

When we talk about climate change, we usually talk about the future, like how much sea level and temperatures are expected to rise.

But Michael Mann wants to look at the earth's past to take lessons on climate change. His new book is “Our Fragile Moment: How Lessons from Earth’s Past Can Help Us Survive the Climate Crisis.”

Mann is director of the Center for Science, Sustainability and the Media at the University of Pennsylvania. He joins host Peter O'Dowd.