Challenges to sustainability arise from the interplay between interacting planetary and human systems and are inevitably embedded in social contexts. Addressing the complex, solution-resistant problems of sustainability thus requires both scientific understanding of the Earth system and consideration of the human values, norms and institutions that that drive unsustainable lifestyles. Geoscience educators who wish to address sustainability issues in their teaching may be comfortable with the scientific aspects of sustainability, but feel less prepared to engage students in exploration of its social, economic, and ethical dimensions. Case analysis is a commonly used cross-disciplinary method for ethics instruction that can provide opportunities for students to grapple with open ended problems, develop awareness of ethical dilemmas related to sustainability issues, consider multiple perspectives. and hone their critical thinking and collaborative problem-solving skills. In this presentation we will: 1) outline a way to conceptualize sustainability that synthesizes scientific, social, and ethical perspectives and 2) present case study analyses, focused on population growth and the climate school strike controversy, to help geoscience educators connect these cross-disciplinary concepts to their classroom practice.