Highlights

Abstract

Keywords

۱٫ Introduction

۲٫ Methodology

۳٫ Barriers and strategies for NBS finance in different ecological domains

۴٫ General barriers and strategies for financing urban NBS

۵٫ Barrier 1: coordination across public and private financiers for urban NBS

۶٫ Barrier 2: valuation and accounting for the multiple benefits of urban NBS

۷٫ Conclusion: a framework for enabling urban NBS finance

۸٫ Limitations and avenues for future research

Declaration of competing interest

Acknowledgements

Appendix A. Supplementary data

References

Abstract

Obtaining public and/or private finance for upscaling urban nature-based solutions (NBS) is a key barrier for reaching urban sustainability goals, including climate mitigation and adaptation. We carry out a systematic review of the academic literature to understand the key barriers and corresponding strategies for financing urban NBS. First, we report on specific financing challenges and strategies found for NBS uptake in four urban ecological domains: buildings, facades and roofs; urban green space (parks, trees); allotment gardens (including urban agriculture); and green-blue infrastructure. Across domains, we identify two overarching barriers of NBS finance: (1) coordination between private and public financiers and (2) integration of NBS benefits into valuation and accounting methods. We discuss strategies found in the literature that address these barriers; here, two things stand out. One, there is a large variety of valuation strategies that does not yet allow for an integrated accounting and valuation framework for NBS. Two, strategies aimed at coordinating public/private finance generally look for ways to encourage specific actors (real estate developers, residents) that benefit privately from an NBS to provide co-financing. We visualize our findings into a framework for enabling (public and/or private) finance for upscaling urban NBS.

۱٫ Introduction

Nature-based solutions (NBS) are a form of eco-innovation that specifically promote nature as a means for providing solutions to climate change (mitigation and adaptation), bad air quality, loss of biodiversity, vulnerable coastlines and other threatened ecosystems, food insecurity and health, social and economic deterioration/injustice (Kabisch et al., 2016, p. 2; Nesshöver et al., 2017, p. 1216–۱۲۱۷). The European Commission additionally emphasizes NBS as a way to realise socially inclusive green growth (European Commission 2015). In general, NBS are recognized for their ability to simultaneously deliver multiple benefits (‘solutions’) to urban sustainability goals, such as biodiversity, climate change mitigation and adaptation, as well as social wellbeing (Kabisch et al., 2016).

NBS are realised in different urban ecological domains such as green buildings, facades and roofs, green space connected to grey infrastructure (playgrounds, street trees), parks and urban forests, allotments and community gardens as well as of different types of green-blue spaces such as lakes, urban drainage systems, permeable surfaces and wetlands. Derelict and former industrial areas and brownfield sites can potentially be re-developed as urban NBS. This diversity of NBS illustrates that NBS are adapted to place-based conditions (Dorst et al., 2019); each ecological domain or context can provide a unique set of services, benefits and values for different urban stakeholders, ranging from ecological services such as climate mitigation and water management to social and economic benefits, such as social cohesion and economic development. Urban NBS often represent local public goods (Besley and Coate 2003)—benefitting primarily those citizens in the area where they are located.