On the need for a multi-dimensional framework to measure accessibility to urban green

With the recent expansion of urban greening interventions, the definition of spatial indicators to measure the provision of urban greenery has become pivotal in informing the policy-design process. By analyzing the stability of the population and area rankings induced by several indicators of green accessibility for over 1000 cities worldwide, we investigate the extent to which using a single metric provides a reliable assessment of green accessibility in a city. The results suggest that, due to the complex interaction between the spatial distribution of greenspaces in an urban center and its population distribution, a single indicator may inadequately differentiate across areas or subgroups of the population, even when focusing on one form of green accessibility. From a policy standpoint, this indicates the need to switch toward a multi-dimensional framework capable of organically evaluating a range of indicators at once.