A common theme in speculative fiction concerns technological overreach. All manner of scenarios have been developed by science fiction authors and filmmakers, warning of the potential for subjugation, obliteration, or alienation as technologies grow in power and scale. Yet within environmental circles, even though the dangers inherent in technological development are well appreciated, environmental challenges are coming to be defined more and more as technical matters to be resolved via technological means. This article explores some of the meaning and limits of this contemporary environmental techno-optimism, through engagement with the “Culture” novels of Iain M. Banks. The Culture novels chronicle a space-faring, post-scarcity civilization, and stand as a kind of best-case extension, in environmental terms, of humanity’s present technological trajectory. The article wrestles with the potential for great benefit but also extraordinary risk that comes with treading down Banks’ path and outlines the kinds of questions that must be asked and answered in an increasingly technology-saturated world. The article distills lessons from comparing Banks’ novels to the “Biosphere 2” experiment. It also explores a few of the ways in which speculative fiction might be deployed in the classroom to better equip students and citizens to wrestle with existing and emerging technologies and their implications.