Deadline 2020 was written for C40, a network of the world’s megacities committed to addressing climate change. The report presents a detailed pathway of what C40 cities need to do to play their part in converting the COP21 Paris Agreement from aspiration into reality. Research and analysis for this report has identified C40 cities’ share of the remaining global carbon budgets to 2100, for 1.5 and 2 degree temperature rise scenarios. The work outlines some of the city-specific action pathways necessary to meet the target trajectories, laying out clearly the pace, scale and prioritisation of action needed between now and the end of the century.