<p>Cities are leading efforts to mitigate emissions and adapt to climate change, yet most comparative studies capture static outcomes rather than the dynamic processes that drive urban transitions. This paper introduces the concept of core dynamics as the finest recurring causal feedback structures that serve as building blocks that collectively shape a city’s transition trajectory. Each core dynamic consists of causal interlinkages among actors, instruments, enabling conditions, outcomes, barriers, and triggers. We propose a framework and derive an initial set of core dynamics from an illustrative base case (Copenhagen) through causal mapping and comparative analysis and then examine their recurrence in two contrasting cases: Canberra and Shenzhen. Our proof-of-concept analysis reveals some common mechanisms of change across diverse urban contexts. Although a larger scale analysis is required to validate and quantify core dynamics across cities, by shifting from static to dynamic process-based comparison, our approach provides systemic insights into not only what cities achieve, but also how and why effective transitions occur. It can therefore help identify common leverage points for more targeted policy transfer.</p>