This chapter also provides the necessary background to green infrastructure (GI) and gives a particular focus to the linkages and connectivity within the GI systems. Green infrastructure, retrofitting, future-proofing social, environmental and economic impacts Introduction As a descriptive term GI was conceived in the USA with a focus on a strategic approach to land conservation and planning, weighted towards ecological processes. The most pragmatic and potentially effective approach to delivering GI benefits is the identification of a primary function or functions which provides the impetus for the inclusion and ongoing management of the GI within the urban environment. A number of GI features effectively provide operational ecosystem services, that are the services that are provided by nature and benefit people, and they face a similar costing challenge analogous to that associated with valuing the services.