This article explores relationships of youth power in a set of threads leading to the potential of today's youth activism to combat the climate crisis. Following an introduction featuring Sweden's Greta Thunberg, the threads are these: First from an American context is history of youth development, with one emphasis on the construction of adolescence. Second is learning experience about the US environment with its own national 'exceptionalist' history. Third is the role of inspiring youth movements, from history and contemporary times. Fourth is a turn to climate activism by youth as central to democracy. One general thematic about youth power across the article is that it oftentimes takes on a mythical character.