Evaluating the effectiveness of green roofs and walls in Nigeria's urban centers: a mixed-methods approach

This study evaluated the effectiveness of green roofs and walls in Nigerian urban centers, focusing on their environmental, economic, and social benefits. Utilizing a mixed-method research approach, the research integrated quantitative surveys and qualitative interviews to provide a comprehensive analysis. The quantitative strand involved a survey of 1000 residents from Lagos, Abuja, and Port Harcourt, while the qualitative strand included in-depth interviews with 30 urban planners, architects, and environmental scientists. Data were analyzed using descriptive statistics, t-tests, ANOVA, and multiple regression analyses for the quantitative data, and thematic analysis for the qualitative data. The findings reveal significant environmental benefits, including reduced urban heat island effects and improved air quality. Economically, green roofs and walls contribute to energy savings and increased property values, although high installation costs and maintenance challenges were noted as barriers. Socially, these infrastructures enhance mental well-being and community engagement, though the degree of support varied. Despite these barriers, the positive perceptions and reported benefits suggest a strong potential for green roofs and walls to contribute to sustainable urban development in Nigeria. Comparative analysis with global case studies revealed that the benefits observed in Nigerian cities are consistent with international findings. The study underscores the need for targeted policy interventions, financial incentives, and public awareness campaigns to overcome the identified barriers. Addressing these challenges can harness the full potential of green roofs and walls, contributing to more sustainable and livable urban environments in Nigerian cities.