Nature-based solutions and green roofs: are Italian citizens willing to pay? A survey investigation in three metropolitan areas

The large-scale installation of green roofs and other nature-based solutions in urban environment can provide multiple benefits for the sustainable development of cities. The implementation of these solutions, in facts, contributes to runoff mitigation during intense rainfall events, to urban heat island reduction, to biodiversity increase and to air quality improvement and it ensures an added aesthetic value. Although these solutions have been largely investigated from a technical perspective to ensure an efficient and effective installation and maintenance, it is also fundamental to evaluate citizens’ perception and willingness to pay. This aspect is crucial for policy makers and urban planners, since without societal interest and approval, these solutions are difficult to implement. In this context, we explore citizens’ interest and willingness to pay for private and public installations of green roofs and other nature-based solutions in three Italian metropolitan areas (i.e., Cagliari, Palermo and Turin), characterized by different climate and socio-economic conditions. Using an online anonymous survey, we investigated how socio-economic background and climate conditions could affect the perception of the most common environmental issues and the interest for urban nature-based solutions. Results highlighted an overall higher interest for green solutions on public spaces than on private ones. Most of the citizens are willing to financially contribute, with an average of 71 €/year, to the construction and maintenance of green roofs and nature-based solutions in public spaces, while the high costs limit the willingness to pay for green solutions on private properties. Results deriving from this study could provide essential insights for decision makers and urban planners to properly define green investments and incentivization policies, fostering the creation of sustainable and resilient cities.