Nature-based Building Blocks (NB3) Framework to support upscaling restoration through NbS in coastal adaptation: Theory, practice, and lessons learned

Coastal landscapes cover only four percent of Earth’s land surface but host around thirty percent of the global population and support key ecosystems that deliver up to two thirds of global ecosystem-service value. Despite their ecological and socio-economic importance, these landscapes face increasingly entangled pressures, including sea level rise, coastal squeeze, biodiversity loss, and pollution. Nature-based Solutions (NbS) are increasingly recognized among promising adaptation strategies to these pressures, yet their implementation remains largely confined to small-scale pilots. The urgent need to scale up NbS for long term, large scale coastal adaptation continues to lag behind due to the intertwined complexities among biophysical, ecological, and socio-economic systems. To address this gap, we developed the Nature-based Building Blocks (NB³) Framework as a transdisciplinary, participatory approach in bridging successful pilot-scale NbS to large-scale coastal restoration. Co-developed across nine restoration pilots within the EU H2020 Rest-Coast project, the framework draws on two complementary, stakeholder-based methodological foundations-the Participative Downscaling Approach and the Input-Process-Output Model-to identify spatially explicit Coastal Units that integrate locally relevant biophysical, ecological, and socio-economic knowledge. Applying the framework across the pilot sites yielded an inventory of Nature-Based Building Blocks to support decision-makers in navigating coastal complexities when developing future upscaling strategies for their pilots. Adding to this inventory, participative practices across diverse coastal contexts revealed key insights into disciplinary gaps and participation biases that inform NbS upscaling research and implementation. The framework shows further potential for scaling out to other ecosystems, such as peatlands and wet forests (in ongoing collaboration with the EU Waterlands project), and scaling across geographical contexts, with an upcoming stakeholder-driven application in the Gediz Delta, Turkey.