Bill McKibben

Bill McKibben is founder of the global climate campaign 350.org. His latest book is "Eaarth: Making a Life on a Tough New Planet." He is also the author of "Long Distance: Testing the Limits of Body and Spirit in a Year of Living Strenuously," "The Age of Missing Information," "The End of Nature" and other books.

Handout photograph shows the Keystone Oil Pipeline is pictured under construction in North Dakota
Global warming hits home Bill McKibben
President Barack Obama and Mitt Romney