Multi-scale analysis of green infrastructure morphology for climate change adaptation

Nature-based Solutions, even if not identified as such, are becoming more and more popular in land planning, especially in cities. Conserving and restoring green infrastructure in urban context is now recognised as being a good practice in the face of climate change adaptation: ecosystem services provided by green spaces can help reduce urban heat island effect and risks of flood, improve resilience of ecosystems to preserve biodiversity and enhance human well-being through access to nature. Simultaneously, cities have to face another challenge: containing land take and urban expansion. The European Commission, in its Roadmap to a Resource Efficient Europe (2011), claimed the “aim to achieve no net land take by 2050”, a goal already transcribed in French law since 2021. Hence, the competition for land use which already existed between housing, industry, roads and recreational purposes will only become fiercer and have to include a new competitor: Nature-based Solutions. In this context, the ability of optimizing the implementation of such solutions – through the different scales at which they provide ecosystem services (building, neighbourhood, city and landscape) – is becoming primordial. Where should we conserve or restore green spaces in priority to ensure the providing of the ecosystem services needed for urban climate change adaptation? This question implies a multi-scale spatial analysis of the impact of green infrastructures on cities. To do so, the question of urban form is tackled by focusing on what is between buildings and streets, where green infrastructure can be deployed and woven into the urban fabric. To establish a multi-scale typology of green infrastructures based on their morphologies, classical approaches are combined with mathematical tools such as fractal analysis for characterizing their dispersion or graph theory for characterizing their connections, essential when studying biodiversity issues. This typology, associated with ecosystem services and biodiversity assessment for different French case studies (including the conurbations of Niort and Dijon), could help understand how to spatially implement Nature-based Solutions within cities, and be integrated into land-planning scenarios.