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Equity assessments of urban ecosystem services/nature based solutions

Urban ecosystems such as manicured green spaces and public parks provide residents with a myriad of ecosystem services (ES). Additionally, the urban greenery has been linked to mental wellbeing and health of residents. The significance of urban ES in benefiting city-dwellers, therefore, will continue to increase. Distribution and type of ES in cities are often determined by local administration branches managing the urban landscape, which includes the amount and extent of reach. However, these management plans do not capture details on actual ES distribution and benefits across population groups, leading to environmental injustice or inequality. Additionally, without a clear definition of equity, evaluation of policy impacts which aim for a more equitable distribution of ES becomes difficult.

Desktop-based approaches have been increasingly employed by integrating empirical data which is available (e.g. LULC maps, infrastructure layouts, master plans, socio-demographic census data) to calculate inequality indices. Such indices can be used to compare inter-city equities or identify suitable locations to implement nature-based solutions to reduce inequalities. The Gini coefficient, Theil entropy index, Atkinson index, are typically used to assess income inequalities. In recent years, these indices have been adapted in non-economic fields, such as equities of carbon emissions and supply of urban ES. However, the full extent of applicability to ES equity assessments has not been well-studied. To answer this, we aim to i) examine the inherent properties of each index on empirical ES supply data; ii) assess the applicability of indices on Singapore as a heterogeneous city and; iii) adopt similar methodologies to other cities for equity comparisons.

Project leads: Perrine Hamel, Aikeen Lim