At first glance Greta Thunberg, a Swedish teenager, seems a very unlikely candidate to become arguably the world’s best known environmental activist. Yet despite her youth and lack of advanced degrees or political authority, she has inspired millions of people to join in the effort to combat climate change. Certainly Thunberg is unique in her global reach, but even a cursory history of women’s environmental leadership reveals countless women operating far outside the bounds of conventional government, yet making a meaningful impact.