A decision-making framework for promoting the optimum design and planning of nature-based solutions at local scale

Urbanization is a key driver of land use/land cover changes climate change. It produces a reduction in natural capital with alteration to the energy budget of land, air ventilation and land surface temperature. The urban morphology derived from the combination of natural capital and human-derived capital is important in urban ecosystem services (UESs) provisioning to mitigate the Urban Heat Island (UHI) effect. Here we report a decision-making framework starting from an applicative case study to assess UESs and promote the best design and planning of Nature-based Solutions (NbS) at local scale. The human thermal comfort has been chosen here as a surrogate to estimate climate regulation as a priority UES in mitigating UHI. The analysis of human thermal comfort in different urban neighbourhood planning scenarios of a city located in Southern Italy has been carried out using the microclimate model ENVI-met. The analysis has been developed to highlight the variation in human thermal comfort in terms of Physiological Equivalent Temperature index (PET) between past agricultural scenarios (no longer more present), current state and several proposed urban scenarios. Such new scenarios have been developed by considering different building arrangements according to municipal planning rules of the city and choosing different types of NbS composition and structure. The analysis has allowed to identify the best scenario characterized by the presence of a community garden with olive groves and estimate the capacity of NbS to reduce the human thermal comfort by about 3.5ºC and improve the PET in selected locations within the current state. In accordance with the aim and topics of the Special Issue, this study shows how such a framework can be useful to support decision-making processes in choosing the best strategy in terms of urban plans and thus making the urban transformation process more sustainable, contributing to assessing the global targets of the 2030 Agenda at local scale.