Green and Gray: New Ideologies of Nature in Urban Sustainability PolicyWachsmuth, D., & Angelo, H. (2018). Green and gray: New ideologies of nature in urban sustainability policy. Annals of the American Association of Geographers, 108(4), 1038–1056. https://doi-org.proxy1.ncu.edu/10.1080/24694452.2017.1417819
This article explains the two distinct representational forms of urban sustainability today, called green urban nature and gray urban nature. Green is the nature in the city (trees, grass, landscapes, gardens), and the gray represents the social and technological, such as public transit.