Despite news reports that highlight danger, the world is actually a much safer place for children than it once was. Accidental death rates for children were much higher in the early 19th and 20th centuries. And yet, children who were once encouraged to go outside and play, are now highly supervised in organized sports and spend more time watching television than playing outdoors. On this Earth Day, Host Charity Nebbe talks with historian Pamela Riney-Kehrberg about her new book "The Nature of Childhood: An Environmental History of Growing Up in America since 1865." In it, Kehrberg looks at when parents became scared to send their children outside to play, and what that fear has cost us.