The existential threat posed by climate change presents a challenge to all those concerned about the next generation. This Element reviews and discusses its implications for the development of children (ages 0-12) today and in the future, and for the parents, teachers, researchers, and professionals who have responsibility for children. This Element adopts a bioecological model to examine both the direct impacts on children's physical and psychological well-being as well as indirect impacts through all the systems external to the child, emphasizing the greater vulnerability of children in the Global South. Given evidence of well-founded climate anxiety, this Element examines children's coping strategies and discusses the key roles of caregivers and schools in protecting and preparing children to face current and future challenges with knowledge, hope, and agency as central themes. This Element highlights many under-researched areas and calls for action by all those caring for and about children's future.