Abstract
Urban heat islands (UHIs) pose increasing risks to human health and energy systems under climate change. Nature-based solutions (NBS) such as green roofs, urban forests, and permeable pavements are widely promoted for UHI mitigation, yet their co-benefits and trade-offs remain insufficiently quantified. This study develops a multi-criteria assessment framework integrating cooling performance, air quality, water regulation, biodiversity, and social equity. Using a mixed-methods approach combining systematic literature review, simulation modeling for a representative mid-latitude city (2020–2023 climate data), and stakeholder workshops, we evaluate five NBS typologies. Results show that urban forests provide the highest cooling intensity (up to 4.2°C reduction) but exhibit trade-offs with water consumption and allergenic pollen emissions. Green roofs offer moderate cooling with co-benefits for stormwater retention, yet their biodiversity support is limited. Permeable pavements reduce surface temperatures by 1.5–2.0°C but may increase groundwater contamination risk. Stakeholder prioritization reveals that co-benefits related to human health and social equity are valued more than biodiversity gains. Trade-off analysis using Pareto frontiers indicates that no single NBS dominates; optimal portfolios combine multiple interventions. Our findings underscore the need for context-sensitive planning that explicitly addresses trade-offs to maximize net societal benefits. The framework supports urban planners in identifying synergies and conflicts, aligning UHI mitigation with Sustainable Development Goals.