The Paris Agreement on Climate Change, Sustainable Development Goals, New Urban Agenda, and Sendai Framework for Disaster Risk Reduction are seeking to construct a new development trajectory. These global commitments both require – and will be supported by addressing climate change in cities. In this Plenary, we exchange knowledge, lessons, and experiences on the impacts of climate change on cities and how cities (their local governments, businesses, and citizens) are adapting and responding to climate change. The Theme 1 Plenary seeks to map the mitigation and adaptation knowledge needs and the gaps being experienced by cities in the context of realizing global commitments. Through interactive dialogue, the Plenary addresses the costs and benefits of climate action and inaction; the underpinning of ethics, equity, and climate justice in the context of climate change, the role of city residents as agents of change, and the imperatives for actions that achieve low carbon, climate-resilient urban pathways, and sustainable development.