Episode 1: The immediate crisis (26 min.)
Though McKibben describes himself as "exuberated and exhilarated and optimistic in many ways," he acknowledges his career "as a professional bummer-outer" and must first lay out the climate change problem before turning to reasons for hope. "Climate change is the most current, immediate crisis," McKibben says in this recording of his Sept. 11 keynote address at the Muddy Boot Organic Festival at St. Philip Neri Parish in Portland, Ore. "We do not have the time we thought we had even a few years ago." (photo by Karen Stein)
NCR staff writer Teresa Malcolm was at the Muddy Boot Festival. Read her story here: A spiritual, ecological celebration 
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About Bill McKibben
Bill McKibben came to prominence as an environmental author and activist in 1989 with The End of Nature, regarded as the first book on climate change for a general audience. Since then, he has written extensively on global warming and alternative energy, and his ideas often come with a spiritual influence (he is active in the Methodist church). Beginning in 2006, he led the organization of the largest demonstrations in the United States against global warming -- a movement that has gone global with the 350 campaign.
Timed to culminate before the U.N. climate change meeting in Copenhagen, Denmark, in December, the 350 campaign draws its name from the number scientists say is the safe limit of CO2 in the atmosphere for life to continue as human beings have known it: 350 parts per million.
A Web-based movement through 350.org , the campaign is working to rally people across the globe for a Global Day of Climate Action this Oct. 24.
The U.N.'s current goals for a climate change treaty are not strong enough to bring the CO2 number back down to 350, McKibben says. "The real negotiation is human beings on the one hand and physics on the other hand," he told the audience at St. Philip Neri Parish's Muddy Boot Festival Sept. 11. "And that's a tough negotiation because physics and chemistry actually are not going to haggle. They've stated their bottom line: Their bottom line is 350. You want a planet like the one you were born on, 350 is our final offer."
The goal of the 350 campaign is to make the voices of ordinary people loud enough so that they will be heard, all focusing the attention on "the most important number in the world."