What do we really know about climate change?

In this episode of John Hook's Newsmaker Saturday, we're looking into the science surrounding climate change. It's the singular issue that seems to be driving nearly all our big public policy decisions right now from energy to national security to our relationship with the planet. The questions are, do we really have a handle on warming? What's causing it? How big of a problem is it? Are the dire warnings outpacing the actual threat? Roger Pielke, Jr. is a professor of environmental studies at the University of Colorado Boulder, one of the world's leading authorities on natural disasters and climate change.