Bill McKibben is founder of Third Act, which organizes people over the age of 60 for action on climate and justice.

His 1989 book The End of Nature is regarded as the first book for a general audience about climate change, and has appeared in 24 languages. He’s gone on to write 20 books, and his work appears regularly in periodicals from the New Yorker to Rolling Stone. He serves as the Schumann Distinguished Scholar in Environmental Studies at Middlebury College, as a fellow of the American Academy of Arts and Sciences, and he has won the Gandhi Peace Prize as well as honorary degrees from 20 colleges and universities. He was awarded the Right Livelihood Award, sometimes called the alternative Nobel, in the Swedish Parliament. Foreign Policy named him to its inaugural list of the world’s 100 most important global thinkers.