Ethics is highly relevant to grand technological interventions into basic planetary systems on a global scale (roughly, “geoengineering”). Focusing on climate engineering, this chapter identifies a large number of salient concerns (e.g., welfare, rights, justice, political legitimacy) but argues that early policy framings (e.g., emergency, global public good) often marginalize these and so avoid important questions of justification. It also suggests that, since it is widely held that geoengineering has become a serious option mainly because of political inertia, there are important contextual issues, especially around the paradoxical question, “What should we do, ethically speaking, given that we have not done, and will continue not to do, what we should be doing?” Taking such issues seriously helps to explain why some regard geoengineering as ethically troubling and highlights the largely neglected threat of interventions that discriminate against future generations (“parochial geoengineering”). We should take seriously the risk that, far from being simply a welcome new tool for climate action, geoengineering may become yet another manifestation of the underlying problem.