This paper opens a discussion on the viral entanglements of childhood and climate change within the posthuman ecologies of educational systems. Working through the conceptual figuration of the ‘climate child imaginary’, we draw on empirical work from a three-year collaboration with 135 children and young people (age 9-14) investigating the experiential impacts of climate change on their everyday lives and educations. The project was open-ended and directly responsive to the creative sensibilities of young people, leading us to explore the potentials of children’s art, film-making, poetics, philosophy, and fiction in developing posthuman imaginaries of climate change education. To our knowledge, this was the first large-scale participatory project to address children’s experiences of climate change through their own creative practices, pivoting on the contested concept of the Anthropocene to engage with climate change outside of conventional nature/culture binaries. Drawing on our forthcoming book, we focus on how children’s ecological art and fiction came to infect the systemic infrastructures of formal schooling like a virus, while also spreading beyond schools to take hold in community libraries, university galleries, and other public spaces. We aim to demonstrate how children’s creative practices can generate an alternative milieu through which educational systems are encountered differently, on terms that are affective, sensorial, and ecological rather than logocentric and universalising. We propose that speculative and artistic modes of inquiry can enable children to work as para-academic researchers and educators, capable of introducing finely tuned pedagogical interventions into educational systems in direct response to critical posthumanist and decolonial concerns. Our project might then be understood as an experiment in working collectively with children and young people to propagate alternative variants of climate change education in the cracks of educational systems, as irreparable and yet fertile ruins of capitalistic-colonial devastation. Crucial to this argument is the reconsideration of children and young people as researchers, artists, writers, scientists, educators, and thinkers who are viscerally attuned to critical issues of social and environmental injustice. We offer this paper as a distinct call for children and young people to actively reshape the very possibility conditions of educational systems through critical speculation and the co-creation of alternative social futures.