A key aspiration for an Ecological Civilization is living well within a postgrowth or degrowth economic system. While the extent of our planetary overshoot is now well documented, policymakers and educators have been slow to imagine how the education system can, on the one hand, help shrink the carbon and material footprints of humanity and, perhaps, just as importantly, develop new conscious and unconscious thinking about life on a “finite” planet (Daly and Farley 2004). As is argued in this chapter, confronting planetary limits is an important first step in developing an ecological or postgrowth subjectivity, which in turn shapes a suitable educational approach for an ecological civilization. A deep understanding of planetary limits has several key features: resource overshoot, no easy technological solutions, impossible to decouple economic growth from emissions, and ex nihilo credit as the key driver of growth and climate change. A postgrowth or degrowth approach to economics is critically engaged with these fundamental problems and the flow-on effects that construct so many of us as rampant and individualistic consumers. Far from being a return to the “stone age,” as some poorly informed critics sometimes assert, degrowth thinking is now emerging as a critical starting point for addressing the destructiveness of economic growth and finding ways to “live well” on a finite planet. Such an approach wrestles with fundamentally pragmatic questions about what human flourishing means within planetary limits and carefully considers how we might build a civilization within these limits. From a postgrowth perspective therefore, many Enlightenment pillars of modernity that supported the old economic growth model are thrown into a new light, including previously fundamental ideas about agency, society, nature, and progress itself (Irwin 2008; Hamilton et al. 2015). These Enlightenment concepts have been key to the premise of universal education and are therefore a site for critique in reconceptualizing the nature of a postgrowth subjectivity and, following on from this, the approach needed for education within an ecological civilization.