Abstract
Cities face significant environmental challenges due to climate change. The lack of green spaces in urban areas can worsen these issues by amplifying the urban heat island (UHI) effect. Socio-economic inequalities further complicate the situation, leading to uneven distribution of climate impacts. Nature-based Solutions (NbS), such as green roofs and walls, offer benefits like cooling effects, enhanced biodiversity, and improved energy efficiency. The JUSTNature project studies the effectiveness of NbS interventions. In Bolzano (Italy), biosolar and high-biodiversity green roofs were implemented on a building in an industrial zone with high UHI intensity. High-resolution microclimate simulations using ENVI-met software, along with local weather data and detailed 3D models, assessed the thermal effects of green roofs. Energy modeling simulations evaluated the impact on building energy performance, including photovoltaic panel output and cost-benefits. Simulations showed significant temperature reductions: over 20 °C in surface temperature and up to 2 °C in air temperature during the hottest day recorded in 2023 (August 23). These interventions resulted in energy savings of 30–46% for cooling, demonstrating their effectiveness in enhancing building energy performance while maintaining indoor comfort. The findings highlight the broader benefits of NbS, such as mitigating UHI effects, promoting urban biodiversity, and creating green corridors in densely built environments. Insights from this project suggest that NbS can support sustainable UHI adaptation strategies, contributing to more equitable environmental transformation in cities.