This article traces a genealogy for the various strands of contemporary psychology which are concerned with global environmental change, including conservation psychology, ecopsychology, and other subfields and interdisciplinary concentrations. Focusing on a network of psychiatrists, psychologists, and other researchers based at a research center founded in Cambridge, Massachusetts in 1982, the article explores what those who first turned to the psychological causes and implications of climate change and other kinds of global environmental disruption had learned from their studies of nuclear-era psychology. The explorations of these researchers and practitioners in systems psychology, depth psychology, and political psychology, elicited by the first truly planetary crisis of the modern world, the threat of general nuclear war (which, apart from the enormous damage done at Hiroshima and Nagasaki and during weapons tests, remained largely theoretical), were applied to a new planetary crisis which was already unfolding: global environmental degradation. As they completed this pivot from the nuclear threat to the environmental crisis, at the end of the Cold War, using the language of the psychology of survival, these researchers displayed the form and function of what might be called a planetary psychology-of psychological theory and practice which broaches the planetary context of the individual psyche.