This lecture discusses the role of social leverage in sustainability, emphasizing the importance of collective action in addressing global challenges. It begins by defining sustainability beyond environmental concerns, linking it to sociopolitical issues such as democracy and human rights. The instructor highlights the significance of ordinary practices and the potential for social forces to transform institutions through collective efforts. Historical cycles of mobilization are examined, showcasing how social movements have evolved over time. The lecture also addresses the concept of collective action, differentiating between individual and concerted efforts to advocate for change. Various forms of collective action, including protests and social movements, are analyzed, illustrating their impact on institutions and public policy. The discussion culminates in the exploration of recent mobilizations, particularly in the context of climate change, and the emerging dynamics of youth-led movements. The instructor emphasizes the need for a dynamic understanding of collective action processes, encouraging participants to engage actively in sustainability efforts.