Climate change threatens major disruption to cities around the world, including from extreme weather events, as well as impacts on infrastructure and resource flows. Simultaneously, cities are framed as sites that offer innovative solutions to climate change via transitions from carbon intensive to low carbon systems of energy, habitation, transport, food, water and waste.

This paper explores how knowledge of global climate change is re-scaled to local levels through city making discourses and practices such as municipal carbon accounting, and conversely how local experiments in low carbon transitions are framed as mobile and replicable solutions to a suite of urban and climate related issues.

Specifically, the author questions how carbon neutrality is being scaled, negotiated and contested in two concrete sites and situated practices of sustainable city making in the cities of Melbourne and Copenhagen. The CH2 office building in Melbourne, and the Nordhavn precinct in Copenhagen, are sustainable building projects aligned with wider municipal goals for community-wide carbon neutrality. Although not commensurate in terms of size, cost, duration and the like, these projects both embody wider visions of the carbon neutrality city held by the respective local governments. The analysis of these projects as ‘urban carbon assemblages’ draws attention to relations between people, ecologies, and technologies as spaces of disruption and innovation, rather than in technologies themselves. These relations are fundamental to how local experiments in low carbon transition play out, underlining the importance of fostering (rather than ignoring) local attachments in local climate governance.