This article develops a series of speculative propositions for an immanent environmental ethics that is responsive to the challenges of the Anthropocene epoch. The article is framed within a new materialist approach to environmental education, and specifically works to re-imagine the notion of justice in terms of performative gestures, multiplicities, processes, and speculative thought experiments. Drawing on Whitehead's speculative philosophy in conjunction with recent new materialist thought, the article proposes the concept of 'doing little justices' as a way of enacting micropolitical interventions into everyday patterns of environmental thought, learning, sociality, and behaviour. The concept of 'little justices' is further elaborated through the analysis of vignettes that problematise issues of climate change, human exceptionalism, ecological sovereignty, and environmental justice with university students in the fields of education and the philosophy of law. The article concludes that an immanent ethics cannot be reduced to a set of predetermined values or prescriptions for environmental education, but should proceed through a speculative process of creative experimentation and negotiation in the pursuit of unforeseen openings and potentials for co-existence.