Resilience

Urbanisation is one of the biggest challenges our cities face today alongside climate change and overall environmental degradation.

The two issues are interlinked: urbanisation is both influenced by environmental issues (Morinière, 2011; Hebbert & Jankovic, 2013) but also contributes to climate change (Kalnay & Cai, 2003; Maheshwari et al., 2020) and excessive resource consumption (Swilling et al., 2018). Urbanisation is also affected by a number of other environmental, social, cultural, technological and economic processes. Cities are complex systems (McPhearson, et al., 2016), consisting of individuals, communities, institutions, businesses and ecosystems, that require the expertise of cross-disciplinary and multi-stakeholder viewpoints in order to ensure their resilience and sustainability.

Resilience describes the degree to which a system is capable of self-organisation, learning and adaptation (Holling, 1973; Gunderson & Holling, 2002, Walker et al., 2004). A system can be anything from a natural ecosystem to a more complex socio-ecological system, like a city. Several definitions for resilience exist, including various conceptualisations and understandings within the concept itself. A fundamental aspect of resilience thinking is that humans and nature are strongly interlinked and should be conceived as a socio-ecological system. 

In recent years there has been a growing emphasis on enhancing the capacity of cities to maintain their essential functions even in the face of impacts from climate change (Meerow et al., 2016).

In this context, resilience is a measurable ability of any urban system, with its inhabitants, to maintain continuity through all shocks and stresses, while positively adapting and transforming sustainably. 

There are seven guiding principles (Table 1) for applying resilience in the management of socio-ecological systems (and the ecosystem services that they provide) that are widely accepted (e.g Biggs et al., 2012). While these principles are not universal and cannot be applied to every system, they nevertheless form a practical  list for implementing resilience principles in many systems (Biggs et al., 2012).

Resilience principle	Explanation
Maintain diversity and redundancy	A system with many components is generally more resilient than systems with only a few components. Components can be e.g species, actors, sources of information). Redundancy refers to spare capacity purposely created within systems to accommodate disruption, extreme pressures or surges in demand. It includes diversity: the presence of multiple ways to achieve a given need or fulfill a particular function.
Manage connectivity	Systems that are connected can overcome and recover from disturbances more quickly than systems with fewer connections. Excessively connected systems may result in rapid spread of disturbances across the system.
Manage slow variables and feedbacks	Controlling the variables influencing system functioning i.e. keeping the socio-ecological systems “configured” and functioning in the ways that provide essential ecosystem services. Once these shift into a different type of functioning (regime), it can be difficult to reverse.
Foster complex adaptive systems thinking	Acknowledging that socio-ecological systems are based on a complex and unpredictable web of connections and interdependencies. Does not influence resilience directly.
Encourage learning	Enhancing the resilience of a system should be supported by continuous adaptive and collaborative learning and experimentation.
Broaden participation	Active engagement of all relevant stakeholders that builds trust and creates a shared understanding is fundamental to building socio-ecological resilience.
Promote polycentric governance	Collaboration across institutions and scales improves connectivity and learning. Well-connected governance structures can deal with change and disturbance swiftly.

Resilience is not synonymous with sustainability. Sustainability, which is most often defined based on the Brundtland commission (1987), refers to a state in which resources are used in such a way that they are not depleted or their use does not decrease the wellbeing of social and ecological systems. It also states that the present use of resources should not compromise the ability of future generations to meet their own needs (WCED, 1987). Building resilience can be seen as a strategy to obtain and maintain sustainability (a system can, however, also be highly resilient but unsustainable). It is thus important in each case to depict what resilience and sustainability mean in a given context, and the factors that can trigger or weaken construction of a system that is both resilient and sustainable. 

The next chapters discuss the principal results of the Augmented Urbans project that are based on the resilience and sustainability concept and offer insight into various case studies implementing or characterising the use of this concept in practice. Subchapter 3.1 gives an overview of the Matrix of Indicators, a tool developed to help planners understand and apply the resilience concept in planning more easily. Also the changing nature of cities has been addressed in subchapters 3.2 and 3.3, while the other subchapters focus on more specific methodological aspects and examples of resilience and the use of XR (including data in general) in urban planning.