The Green Area Ratio: an urban site sustainability metric

The Green Area Ratio (GAR) is an urban site sustainability metric which has been used in Berlin, Germany since 1997 to enhance the urban environment by requiring green infrastructure enhancements on private properties. Following an overview of the principles of the GAR instrument, this paper outlines metric development and implementation procedures in Berlin and then analyses how instrument features might affect its potential environmental, social and economic impacts. Despite identified policy deficits and the lack of adequate outcome monitoring in Berlin, the GAR instrument resonates with the environmental planning needs of many urban communities, including its compatibility with dense urbanism, utilisation of green infrastructure techniques, and an aim toward comprehensive environmental planning.