“Spongetown” Christiania as an urban living lab: Nature-based solutions for resilient, circular, symbiotic, and regenerative transitions in urban waters

Rising sea levels and stormwater flooding threaten coastal ecosystems like wetlands, exacerbating urban sustainability challenges. Urban Living Labs and NBS propose decentralised, community-driven approaches emphasising resilience, circularity, symbiosis, and regeneration. This study examines Freetown Christiania, a pioneering community-led urban laboratory and countercultural enclave within Copenhagen’s socio-technical-ecological systems, as they pursue SDGs within planetary boundaries. We analyse Christiania’s urban niche using participatory observation and sociotechnical frameworks—including Actor-network Theory, the Multi-Level Perspective, and Sociotechnical Imaginaries. We investigate NBS innovations, such as reed bed systems, constructed wetlands, green roofs, and green-blue infrastructure, which exemplify Christiania’s integrated urban water management—innovations reshaping Copenhagen’s grey infrastructure path dependency, driven by Danish agendas and Sino-European sponge city partnerships.

Identifying key actors, drivers, barriers, and scenarios, our thematic analysis codes problems, interests, and strategies to articulate a proposal for expanding Christiania’s NBS niches through urban planning and governance. Findings highlight Christiania’s contributions to NBS in wastewater treatment, habitat preservation, biodiversity monitoring, and sustainability ideology. The Freetown bridges community-led innovations with municipal and international strategies, positioning itself as a potential pilot for further integrating socio-technical, techno-economic, socio-ecological, and institutional design approaches to urban and coastal sustainability.

We propose a replicable multi-criteria methodology for territorial transitions in Copenhagen, the Baltic, and globally. Based upon IUCN and DGNB standards, we outline criteria for urban NBS proposals developed with Christiania’s Building Office and local stakeholders. These criteria inform scenario planning in our project, “Spongetown Christiania,” forecasting trajectories and pathways for local governance of infrastructure, urban renewal and development.