The future of sustainable urbanism: a redefinition

In this article the future of sustainable urbanism is discussed. In current times a complex of uncertainties demands sustainable environments. Three uncertainties are distinguished. Firstly, the city needs to deal with uncertain developments, such as the impacts of climate change. Secondly, urban environments are the place where deliberate uncertainties, such as the generation of renewable energy and other sustainability transitions must find a place. The third form of uncertainty is the increased exposure of urban populations to the impacts of a spectrum of uncertain developments, climate impacts. This ‘Triple-U problem’ urges the design of urban areas to be sustainable. Sustainability has long been a part of urbanism, however, in completely different ways in different periods in history. When learning from the past, the analysis of sustainable urbanism in seven periods brings key elements to the fore. Sustainable urbanism has evolved, but key characteristics of each period may and can still be used to design sustainable cities. Based on these characteristics two strategies, and a potential third one, are identified: to fix the future, to indulge the future, and to create anti-fragile urban environments. Where fixing the future implies the reparation of environmental qualities and closing environmental flows within the urban boundaries, indulging the future focuses on the creation of sufficient space to accommodate the possible spatial impacts of unprecedented events and change. Anti-fragility supports the city in raising its resilience under threat of uncertain impacts. The article ends with a proposed renewed definition of sustainable urbanism.