The international community is negotiating a new global climate agreement to be applicable from 2020 onwards. Parties aim at signing the agreement in December 2015, at the Conference of Parties (COP) in Paris. Until then, countries are already preparing proposals for their individual contributions, their Intended Nationally Determined Contributions (INDCs). The INDCs will, besides other elements, include mitigation contributions as central elements. Negotiations under the ADP have advanced and more concrete discussions are taking place, with the objective to finalise the new climate agreement in December 2015. Many Parties and other stakeholders have expressed additional ideas and concrete suggestions on how to design mitigation commitments under the 2015 agreement. Further research has emerged on design options and priorities of individual countries. This report is a synthesis of the research and re-evaluates the options previously considered in this project (Vieweg et al (2014)) in the light of the negotiation process up to today. The mitigation related design elements considered are:

• Participation and differentiation of countries;
• Types of commitments, including also the compulsory character of the commitments and time aspects;
• Guidance on ambition of the commitments to assure adequacy of global and individual countries’ efforts;
• Transparency of commitments.

For each of these elements, this report illustrates the current status of the negotiations and explains the implications of the options on the table. It further gives some recommendations on how the elements could be designed in an effective and equitable way.