This lecture was based on research for the Global Commission on the Economy and Climate. It presents the findings of the cities research programme of the Commission’s New Climate Economy (NCE) project which LSE Cities is leading. The overall aim of NCE is to provide independent and authoritative evidence on the relationship between actions which can strengthen economic performance and those which reduce the risk of dangerous climate change. It has been repeatedly argued that cities have a unique opportunity to build a different model of economic growth – one which achieves the benefits of growth but with significantly reduced greenhouse gas emissions alongside co-benefits such as improved health. And it is commonly understood that this will require a focus on actions that are systematically important for how cities function, including decisions around urban form, city design and transport. This lecture featured some of the core findings and arguments that were recently published in the first NCE publication ‘Better growth, better climate’ and position the role of cities as part of a global green economy transition.