As Super Tuesday is in full swing, we dig down into a key issue for the Democrats: climate. Paul Polman, the former CEO of Unilever, tells Amanpour why investing in climate solutions could unlock economic growth. Environmentalist Bill McKibben was one of the first to sound the alarm on the climate crisis over twenty years ago - he lays out how divestment efforts are affecting the fossil fuel industry. Then Robert Bullard, the author and celebrated environmental scholar, sits down with our Walter Isaacson to highlight how climate change is intrinsically linked to race and segregation. He explains how minority communities in Houston suffer most from pollution.To learn more about how CNN protects listener privacy, visit cnn.com/privacy