Policy mixes for mainstreaming urban nature-based solutions: An analysis of six European countries and the European Union

Nature-based solutions (NBS) are multifunctional and cost-effective innovations delivering urban sustainability, but they are not yet mainstream in urban development. This can be explained by persistent structural conditions in the urban infrastructure regime, resulting in barriers such as lack of collaborative governance, inadequate knowledge and limited funding availability. In this paper we argue that (supra)national governments could play an important role in breaking down these barriers by employing policy instruments and strategically combining these into policy mixes targeting multiple regime structures. By means of an empirical analysis across six European countries and the European Union (EU), we provide an overview of regulatory, financial and soft (supra) national policy instruments supporting urban NBS mainstreaming and how these are combined in policy mixes across cases. In addition, we investigate policy mix comprehensiveness by mapping the extent to which these target each of the relevant urban infrastructure regime structures underpinning barriers to urban NBS mainstreaming. We demonstrate that, with the exception of the EU, none of the studied cases employs a fully comprehensive policy mix. We conclude that by strategically adopting policy instruments with the aim of crafting a comprehensive policy mix, obstacles in pathways to urban NBS mainstreaming could be overcome.