Exploring the potential for nature-based solutions to cool the streetscapes of a densely urbanised Mediterranean city

Rising temperatures due to climate change are expected to have a greater impact on cities, compared to rural areas, due to the Urban Heat Island (UHI) effect. In cities of the Mediterranean Basin, cooling of the urban microclimate is becoming a priority for practitioners, stakeholders, citizens and public authorities. The use of Nature-based Solutions (NbS) to address the UHI effect is often advocated in the literature but there are few accounts of these interventions in high-density historical cities. This study focuses on Cottonera, a densely populated urban area with extensive soil sealing and low natural cooling capacity on the island of Malta. Since many residents already place potted plants in the streetscape outside their homes, this informal urban greening of public space provides a currently untapped resource which could be maximised to form coordinated NbS interventions to cool the streetscape. To explore this possibility, the vegetation placed in the streetscape is surveyed for its current and potential capacity to provide shading to pedestrians, whilst an analysis of the spatial constraints of the urban fabric informs appropriate interventions for the case study area. Residents are asked for their thoughts on urban greening and their willingness to participate in such a project as an initial step towards a participatory planning approach. Three types of NbS are proposed that could be co-implemented alongside the community to achieve place-based hybrid NbS.