Environmental Justice Implications of Nature-based Solutions in Urban Areas: A Systematic Review of Approaches, Indicators, and Outcomes

Environmental justice (EJ) addresses the unequal distribution of environmental goods and harms and promotes people’s right to be involved in environmental decision-making. In recent years, EJ considerations have expanded to the use of Nature-based solutions (NbS) in urban areas, mainly how their planning and implementation can impact human well-being and social justice. However, what constitutes a just solution and how the concept is treated in the literature can take many forms. This study reviews how EJ is conceptualised and analysed in urban NbS research and documents the potential outcomes of diverse interventions. We developed a conceptual framework for the review process, focusing on the EJ definitions transferable to NbS research. We then conducted a systematic review of 152 articles published between 2000 and 2021. Selected articles addressed urban NbS from the recognitional, procedural and distributional interpretations of justice. Publication trends, methods, and demographic variables were recorded for each article. Furthermore, we focused on the means for assessing EJ in empirical terms, such as the framing of justice-related challenges, assessment indicators, and the reported justice outcomes. Findings demonstrate the dominance of research themes, the skewness towards the distributive dimension of justice, and a large variety of metrics and indicators used to assess EJ implications. Our results also show that EJ outcomes have mostly been reported to be mixed or negative. The results are used to identify research gaps and issues that need to be addressed to enhance EJ effects in urban NbS.