Age: 51
Occupation: Writer, environmental activist
The former New Yorker writer and author of a number of award-winning environment books led the online insurgency that forced President Obama to block the Keystone oil-sands pipeline. McKibben — not a professional environmentalist or activist but a cross-country-skiing Sunday-school teacher who lives in a cabin in Vermont — has quite suddenly laid claim to being the most influential voice in the green community. But while he's great at mobilizing the choir, can he really convince people across the partisan divide?