The international climate community puts increasing hope into climate solutions at urban scale. Research also increasingly emphasizes the role of cities in climate change mitigation. A main trope of research has been identification of climate action in specific cities, through case studies. These empirically-grounded and bottom-up insights contrast with a dominant strand in climate mitigation research that makes use of global models to explore long-term low-carbon futures, where local solutions can often be minimally represented. The time is ripe to put the scientific investigations on urban climate solutions on more systematic foundations by structuring insights on causal interventions and processes across different time scales, individual behavior and policy choices, and by upscaling urban solutions to a global scale, by typologies or otherwise.