Much has changed since the European Commission published in 2011 “The roadmap for moving to a competitive, low carbon economy in 2050.” The Paris Agreement created a new global framework to address climate change, and many of the assumptions—including technological and scientific ones— on which the 2050 roadmap was built have changed. In March 2018, the European Council invited “the Commission to present by the first quarter of 2019 a proposal for a Strategy for long-term EU greenhouse gas emissions reduction in accordance with the Paris Agreement.” This technical paper accompanies a shorter policy paper, and is the outcome of a year-long effort, which included a series of stakeholder engagements in five EU capitals at the beginning of 2018. It is produced under the project “Developing the EU Long-Term Climate Strategy, ” a joint initiative of Bruegel and the European Roundtable Climate Change and Sustainable Transition (ERCST/ICTSD). The technical paper seeks to explore the choices that need to be made across the main issues that might need to be included in the development of a new EU long-term climate strategy, as well as the analyses of potential trade-offs implied by these choices.