This chapter examines the position of the UN Security Council within the institutional framework on environmental peacebuilding. It starts with an analysis of the UN's peacebuilding architecture, which assigns complementary roles to the Security Council, the General Assembly and the Economic and Social Council, based on each organ's respective function within the UN system. The chapter then turns to the practice of the Security Council with respect to 'conflict resources' on the one hand and environmental degradation more broadly on the other. This analysis demonstrates major differences in the substantive contributions by the Security Council with respect to 'conflict resources' on the one hand and to climate change and other ecological threats on the other. It argues that the institutional division of responsibilities between the three main UN organs provides a powerful rationale for explaining these differences.