The views expressed herein can in no way be taken to reflect the official opinion of the European Union. The agreement is to be adopted by 2015 and come into effect from 2020. An effective agreement would include quantitative mitigation commitments from all major emitters and result in concrete actions to reduce greenhouse gas emissions while catalysing long-term transformations to low-carbon and climate-resilient economies. The aim of this paper is to explore what mitigation commitments put forward under the 2015 agreement might look like, what guidance might be agreed regarding the type of commitments proposed, and which “rules of the game” would need to be agreed before draft commitments for the post-2020 period are put forward.