This paper explores options for a hybrid approach in the 2015 global climate change agreement, focusing in particular on mitigation efforts. This emerging approach seeks to balance national flexibility and international discipline to produce greater ambition. The paper looks at the rationales for a hybrid approach, ways to design hybridity into an international agreement, and how top-down and bottom-up approaches have figured in the UNFCCC’s evolution. It also examines the types of top-down features that could complement nationally determined contributions to promote greater ambition, including a long-term goal as a benchmark for evaluating countries’ efforts, reporting and review procedures to promote transparency and accountability, and provisions for updating or initiating the next round of commitments. It also considers cross-cutting issues such as timing, the overall structure of the agreement, the differentiation of countries’ obligations, and ways to make the 2015 agreement dynamic and, in turn, durable.