Prospects for a circular bioeconomy in urban ecosystems: Proposal for a theoretical framework

The interconnectedness of value chains, the different motivations of actors, and the complexity of urban ecosystems (UE) have given rise to calls for more comprehensive approaches to diagnosis urban sustainability. In this regard, the circular bioeconomy (CBE) is attractive for, in theory, it ensures regenerative capacity and offers the possibility of improving the resilience of ecosystem services. However, there is a risk that the delineation of the narrative will be limited to issues narrowly defined by key actors, without considering value creation beyond financial. This paper explores how the alignment of CBE principles can support the services provided by UE, considering their socio-ecological needs. To this end, we propose an adaptive theoretical framework supported by a qualitative and comparative analysis of the current scientific literature. The main contributions of the paper are: (i) propose an original structure using the nature-based solutions (NbS) concept as background and (ii) provide a new typology built from the biophysical boundaries, drivers, barriers, strategies, and indicators identified. The framework presents itself as an instrument capable of guiding further research in the thematic area, facilitating the identification of trade-offs, benefits, and co-benefits, and represents a step forward in the search toward generalisation, reducing uncertainties and utopian notions that mould the CBE.