Yale Environment 360: Author Bill McKibben first warned about global warming and its implications for the planet in his 1989 book, The End of Nature. But in the last few years, it has become the focus of his work as an organizer of 350.org, an advocacy organization promoting global action to tackle climate change. In an interview with Roger Cohn, McKibben described why he is working fulltime on the issue, why he thinks a citizens movement is essential for giving President Obama the “political space” …