A review of approaches and challenges for sustainable planning in urban peripheries

As urban systems continue to grow worldwide, urban peripheries increase in number and typologies, which makes their planning a challenge for sustainable development. The aim of this article is to explore approaches and challenges related to the application of sustainable planning to urban peripheries. We reviewed the content of 102 papers related to sustainable planning in urban peripheries by applying a framework built on two main research questions that address: i) the type of peripheries and sustainable planning approaches considered; ii) the challenges and recommendations reported. The results show that urban peripheries are difficult to synthesize in operative classifications, and are not central in the discourse on sustainable planning approaches. The studies described are mainly context-specific and solution-oriented, aimed at responding to local socio-economic and ecological issues, and the analysis reveals uncertainties about their transferability to other geographical contexts. Few common trends can be highlighted, but many authors acknowledge the cross-cutting risks and trade-offs related to the complexity and dynamism of urban peripheries, which may eventually lead planning to unsustainable or unlivable outcomes. Integration among different scales and sectors emerges as a requirement for effective sustainable planning. We conclude with a remark on the underexploited opportunities offered by urban peripheries, especially with regard to ecological planning approaches.