LULU GARCIA-NAVARRO, HOST: Now, there is no reasonable question that climate change is fueling these events and others around the globe, but there are questions about the details - why, even though the big picture is clear, the local effects of a warming planet are occasionally surprising. Michael Mann is a distinguished professor of atmospheric science at Penn State University, and the author of "The New Climate War: The Fight To Take Back Our Planet." We turn to him now because, you know, he's got a pretty good track record on climate predictions. MICHAEL MANN: Well, it's a bit frustrating. As a climate scientist, the last thing you want to see is your predictions come true. And unfortunately, you know, despite the fact that decades ago we warned that if we continue to add carbon pollution to the atmosphere through the burning of fossil fuels that we would see not just an overall warming of the planet, the melting of ice and sea level rise, but more extreme weather events. And now the signal of climate change in the weather has emerged from the noise. What that means is that we can actually see climate change in the individual extreme weather events that are playing out right now across the northern hemisphere this summer. This is climate change.