This report, written by Dr Tim Braunholtz-Speight, Prof. Carly McLachlan and Harry Barton, provides a summary of key themes and questions that emerged from discussions at the online International Round Table on Accelerating Climate Mitigation at City Level hosted by CAST, The Tyndall Centre for Climate Change Research and the Greater Manchester Combined Authority (GMCA), giving an indication of the pressing issues and current approaches being adopted by those at the forefront of making climate change mitigation happen at city and regional scales.