Climate change is increasingly characterized as a security issue. Yet we see nothing approaching consensus about the nature of the climate change–security relationship. Indeed existing depictions in policy statements and academic debate illustrate radically different conceptions of the nature of the threat posed, to whom and what constitute appropriate policy responses. These different climate securitydiscoursesencourage practices as varied as national adaptation and globally oriented mitigation action. Given the increasing prominence of climate security representations and the different implications of these discourses, it is important to consider whether we can identifyprogressivediscourses of climate security: approaches to this relationship underpinned by defensible ethical assumptions and encouraging effective responses to climate change. Here I make a case for an ecological security discourse. Such a discourse orients towards ecosystem resilience and the rights and needs of the most vulnerable across space (populations of developing worlds), time (future generations), and species (other living beings). This paper points to the limits of existing accounts of climate security before outlining the contours of an ‘ecological security discourse’ regarding climate change. It concludes by reflecting on the challenges and opportunities for such discourse in genuinely informing how political communities approach the climate change–security relationship.