text:  It's Here and Now. For many people, life follows a conventional course, learning, earning, and then retiring. But because we're living longer than we used to, lots of older people are reinventing themselves in surprising and inspirational ways, designing a third act. We've been featuring some of these stories, and today we hear from climate activist Bill McKibben, who designed his own third act, an effort to recruit people over age 60 to help save the planet and democracy.