Urban Green Infrastructure for Climate-Resilient Cities: A Systematic Review and Thematic Synthesis of Environmental, Social, and Economic Benefits (2000–2022)

Background The urgent need for multifunctional, nature-based solutions has been produced by the increased environmental, social, and economic strains on cities because of accelerated urbanization. Urban green infrastructure (UGI), which includes parks, green roofs, wetlands, and street trees, provides critical ecosystem services (ES) that enhance climate resilience, enhance environmental quality, and support social well-being. The current research is divided, with an excessive emphasis on regulatory services and an inadequate consideration of co-benefits and equality issues.Methods A systematic review was conducted by integrating 690 empirical articles published from 2000 to 2022, utilizing the Collaboration for Environmental Evidence criteria. The advantages of urban green infrastructure in the supplies, regulating, sustaining, and cultural ecosystem service categories, as defined by the Millennium Ecosystem Assessment, were examined using bibliometric mapping, quantitative synthesis, and narrative theme analysis.Results The most frequently documented topics were urban heat reduction, stormwater management, and air quality enhancement, with regulatory services comprising most of the literature (77.5%). Green roofs in tropical regions decreased air temperature by 1.4°C, while parks in temperate regions decreased mean air temperature by 2°C and land surface temperature by 6.2°C. Provisioning, supporting, and cultural services were each underrepresented, with less than 8% each. Affluent countries were favored by geographic bias, while only 17.7% of heat-related research evaluated co-benefits. Operational feasibility, equity evaluations, and longitudinal performance data were rarely considered.Conclusions Although UGI provides significant, quantifiable environmental and social benefits, its integration into urban policy is complicated by a lack of research on underrepresented service categories, equality, and operationalization. Standardized assessment frameworks, interregional research, and innovative finance methods are essential for the expansion of urban green infrastructure as a cost-effective and equitable climate adaptation strategy.