Who governs climate adaptation? Getting green roofs for stormwater retention off the ground

Abstract

Green roofs are an innovative solution for urban stormwater management. This paper examines governance arrangements for green roofs as a ‘no-regrets’ climate adaptation measure in five cities. We analysed who governs green roofs, why and with what outcome. Our results show that hierarchical and market arrangements co-exist in the various stages of the policy process. Cities with a higher prevalence of hierarchical arrangements have substantially higher implementation rates for green roofs. Although private sector involvement is crucial for raising efficiencies, a significant level of public responsibility taken by local governments appears to be salient for unleashing the potential of green roofs.

Keywords:

• climate adaptation
• responsibilities
• governance arrangements
• green roofs
• cities

Acknowledgements

This research is funded by the Dutch Knowledge for Climate Research Programme ( http://knowledgeforclimate.climateresearchnetherlands.nl/). The authors would like to thank Clare Barnes and Tina Newstead for the English language check, and the three anonymous referees for their very helpful comments.

Notes

1. Various studies show that rainfall retention of green roofs ranges from around 30% to nearly 90%, depending on the depth and material of the substrate, the vegetation used and the slope of the roof (see e.g. van Woert et al. 2005, Mentens et al. 2006, Villarreal 2007).

2. Green roofs prolong the roof life (Wong et al. 2003, Kosareo and Ries 2007); insulate buildings from both heat and cold, thus reducing energy bills for heating in the winter and air conditioning in the summer (Wong et al. 2003, Sailor 2008); insulate against noise (van Renterghem and Botteldooren 2011); have higher (perceived) aesthetic values than a regular roof (White and Gatersleben 2011) and might therefore raise the value of a property.

3. In the (environmental) governance literature, deliberative network arrangements are claimed both to enhance and to reduce democratic values such as legitimacy and democracy (for a discussion see e.g. Bogason and Musso 2006, Lemos and Agrawal 2006, Juhola and Westerhoff 2011).

4. The supplementary materials (online only) consist of a detailed overview of the respondents and the interview guide.

5. In Chicago, primarily the Department of Zoning and Planning and the Mayor's office; in Rotterdam, primarily the departments of water management and of Rotterdam Climate Proof; in Stuttgart, primarily the department of Urban Planning. In Basel, the Canton authorities are the main public actor, in particular the ‘Stadtgärtnerei’ (the urban greening department); and in London the Greater London Authority, the Environment Agency and the planning departments of the 33 boroughs.