Abstract
Climate change presents one of the most significant challenges to society today. Effects on ecosystems and culture are strongly felt in cities, as about half of the human population globally lives in urban areas. In addition to climate change, urbanization and the continuous increase in the number and size of cities are impacting ecosystems with various threats. For example, urban overheating is one of the most critical problems of the urban environment, significantly impacting the energy demand, especially for cooling, thermal comfort, health, and pollution. On the other hand, there is an increasing interest, because of the pandemic, in the link between the city, equity, and health. Above all, the environmental risks in urban areas affect people who are highly exposed to thermal discomfort and pollution. Features like nature-based solutions can improve urban health for all, let alone for elderly and vulnerable people. Nature-based solutions (NBS) can successfully cope with these adverse effects of extensive urbanization, climatic change, and pandemic conditions. They can foster and simplify implementation actions changing how urban landscapes perform, look, and are critical resources in defining a healthy and equitable city mode. They are mainly known for their regulation of climate, air, and water quality and the mitigation of extreme hydro-meteorological events; for sustaining biodiversity and habitats; furthermore, aesthetic values related to spiritual development and recreation and tourism. Most of the existing studies related to measure or model thermal mitigation properties of NBS, whereas others reflect air quality. Other studies focus on how NBS impacts people's behavior and their psychic-physiological health. Furthermore, NBS have improved mental health, reduced mortality, and promoted easily accessible physical activity in a mixed urban environment, reducing the risk of obesity and diabetes. Despite the increasing evidence for the many benefits of NBS, their effectiveness to climate change adaptation has not fully translated into measurable evidence‐based targets and actions “on the ground”. There is a lack of synthesis of the evidence, especially concerning approaches that suggest bottom-up solutions, where the results could be thoroughly observed and qualified. Many studies look at the technical benefits of NBS (e.g. local climate impact on temperatures and air quality). Still, the suggestion that NBS can be a vehicle to produce better solutions for local problems based on citizens’ experience and behavior is yet to be measured. Considering citizen participatory trajectories, especially in the early planning and implementation of NBS might be crucial since the opinions, perspectives, and (tacit) knowledge of residents can assess the quality of NBS as they are incorporated into their culture, daily habits, traditions, and knowledge. The research, thereby, formulates a multi-domain frame for practically implementing localized holistic studies encompassing carbon footprints, energy figures, thermal quality, air quality, health, people involvement, acceptance, and behavior, along with their response. It will do so by analyzing the state of the art that regards a) methods and techniques to measure environmental impacts on NBS (decarbonization, climate mitigation, reduced building energy loads, etc.), b) methods and techniques to measure thermal comfort, thermal delight, health (biometric), and including biophilic aspects and c) methods and techniques to measure social impact (collective acceptance and behavior, reaction). It is expected that this kind of research might allow the emergence of a basic local system to measure and observe, quantitatively (deterministic) and qualitatively (socially constructive) the impact of NBS in the city building a holistic assessment of NBS that now is missing together with the qualitative measures. The range of tools used for measuring NBS performances includes technical equipment data-logging environmental flows to the use of new smart technologies, visualizing tools to track people's behavior.
