The article examines the ecological crisis as a cultural and mythological phenomenon and as a major source of myth-making in science fiction of the late twentieth and early twenty-first centuries. The study is relevant due to the growing prominence of environmental issues in contemporary science fiction and their role in articulating collective fears and hopes related to global threats. The paper aims to identify and classify ecological mythologemes that emerge amid the crisis of the anthropocentric worldview. It outlines theoretical approaches to the concept of the mythologeme and argues for its specific functioning in science fiction, where mythological models of world perception are correlated with scientific conceptions of reality. Particular attention is paid to the mythologemes of ecological apocalypse, vengeful/autonomous nature, the lost paradise, and the posthuman world, as well as to the transformation of the image of humanity from an agent of catastrophe to a possible savior. The study employs myth-critical, cultural-historical, and comparative-typological methods, incorporating elements of ecocriticism.