Beating around the bush: A scoping review of trade-offs for just planning and governance of urban nature-based solutions

Urban nature-based solutions (NBS) are increasingly embraced by academics and practitioners for their ability to contribute to sustainability by addressing various urban challenges such as air quality, urban heat stress, urban flood mitigation, biodiversity loss, and social cohesion. Research in the literature places a significant focus on the identification of synergies and win-win scenarios of urban NBS. However, this has caused a blind spot in necessary research on trade-offs. Specifically, the existing research on trade-offs lacks a holistic overview of empirical evidence on urban NBS trade-offs from diverse fields of research, and current discussions on trade-offs inadequately reflect on the political nature of the choices and consequences of trade-offs when planning and governing for and with urban NBS. This paper addresses these issues by providing an overarching typology of urban NBS related trade-offs and the environmental justice implications thereof through a scoping literature review of empirical research on urban NBS trade-offs from different fields of research. The review provides an overview of the variable understandings of trade-offs of NBS, the usage of spatial and temporal scales when addressing them, and categorizes trade-offs according to stages of the planning cycle. We identify three main groups of urban NBS trade-offs, namely, rigid, governance, and functional trade-offs, and illustrate their different manifestations across the planning cycle. The typology sheds new light on research of urban NBS trade-offs by explicitly placing an environmental justice perspective on the types of trade-offs, and linking these types with the planning cycle. Thereby, this paper contributes to a new understanding of urban NBS trade-offs for planning and governance by illuminating the implications of choices for who or what is recognized, participates, and benefits from nature in the city.