Chikyuu to no Yakusoku is a single-episode educational OVA from 2018, produced as a non-commercial work rather than for theaters or television. It belongs to the "Save our mother earth" project, whose aim is to raise public awareness of global warming. The project takes its name from essays on environmental issues by the late Tezuka Osamu, and its anime has been screened in schools and communities across many parts of Japan.