Climate change is an environmental and existential issue of great urgency, especially for today’s youth. Until recently, the French national school curriculum had not given students much opportunity to learn about climate change (CC), its causes and repercussions, and mitigating measures to reach sustainable climate conditions. This article describes a six-week participatory, experiential workshop that brought together two groups of French students (one age 10 and the other age 16) to learn and teach each other about CC. Older students learned about the Conference of the Parties, COP21 Paris agreement and the IPCC climate findings and recommendations. Together the two groups developed greater understanding about CC, and proposed concrete environmental actions that they could undertake at home and in their local district to reduce greenhouse gas (GHG) emissions. We examine four products of their collaboration:● slide presentations that they created jointly, ● students’ written reflections on learning about sustainability and CC, ● the group’s list of proposed personal and family actions to decrease their carbon footprint, and ● notes from a meeting with local governmental officials. We draw inferences from these sources, and extract two recurrent themes in the students’ learning. These themes highlight a mismatch between youth’s sense of urgency to respond to the climate emergency and the older generation’s sluggish pace of addressing it. This article is a qualitative case study of a successful attempt to raise students’ awareness of sustainability and climatic issues, and to involve them in thinking collaboratively with others about the tasks ahead to address the problem of climate change from a local perspective.