Impacts of green roofs on water, temperature, and air quality: A bibliometric review

Green roofs are an effective nature-based solution to eco-environmental problems arising from climate change and rapid urbanization because they provide multiple ecosystem services and can have a significant positive impact on human well-being. To explore state-of-the-art research, deficiencies, and development trends related to green roof ecosystem services, the “Bibliometrix” R package and “CiteSpace” were used to conduct a quantitative analysis of 1623 English language sources published in Scopus before 2020. Results show that since 1981, the amount of research on green roofs has steadily increased with approximately 40.9% of the articles focusing on regulating services in the contexts of water, 30.0% on the thermal environment, and 3.5% on and air quality. Green roofs have proved effective at reducing urban stormwater management pressures, mitigating the urban heat island effect, reducing energy consumption, and improving air quality. However, no standard assessment methods and tools exist to value green roof ecosystem service delivery; a balance and coordination between different service values are lacking. Future research should focus on customizable low-cost and innovative green roof designs, increasing the number of quantitative case studies, and conducting multi-perspective evaluations. Considering how environmental, social, economic, and other benefits can be achieved on a larger scale is also necessary. Overall, this review helps advance research on green roofs and guide wide-spread implementation in urban areas in response to environmental challenges.