Can policy instruments enhance the benefits of nature-based solutions and curb green gentrification? The case of Genova, Italy

New policy solutions are necessary to make cities more liveable in a future that will be hampered by climate change, urbanization, landscape fragmentation and overall overexploitation of limited resources and space. There is an aspiration to continue to integrate Nature-Based Solutions (NBS) into global agendas to cope with climate change and urbanization due to their multiple benefits and co-benefits. Nevertheless, socio-economic and especially negative impacts of NBS are rarely considered and integrated into policy literature. Hence, the objective of this study is to address this gap by simulating three different policy instruments to mitigate green gentrification and enhance the impact of co-designed NBS in Genova. For that purpose, the spatially explicit hedonic pricing simulation model SULD (Sustainable Urbanizing Landscape Development) was used to simulate a linearly decreasing property tax to high-income households, a property tax subsidy provided to low and middle-income households and a zoning buffer policy around the NBS implementation area. Results show that all policy instruments have the ability to curb green gentrification, however the property tax subsidy led to added urban expansion, fostering urban sprawl. Both the zoning buffer and the property tax had better overall socio-economic and land use impacts by curbing green gentrification, posing little impact on low-income households and maintaining urban contraction, even though this contraction was smaller for the property tax instrument. Hence, it can be concluded that a policy mix including information, planning and economic instruments may be most effective to enhance the impact and mitigate green gentrification of NBS.