We are entering a new urban era where the planet is increasingly influenced by human activities and where cities have become a central nexus of the relationship between people and nature, both as crucial centers of demand for ecosystem services, and as sources of environmental impacts.1,2 However, in the next two to three decades, we have unprecedented chances to vastly improve global sustainability through designing urban systems for increased resource efficiency, as well as through exploring how cities can be responsible stewards of biodiversity and ecosystem services, both within and beyond city boundaries.3 Two central concepts for achieving this—urban sustainability and urban resilience—have, however, until now rarely been applied beyond city boundaries and have often been constrained to either single or narrowly defined issues (e.g., population, climate, energy, water).4,5,6 Although there is often an aim to optimize resource use in cities, increase efficiency, and minimize waste, cities can never become fully self-sufficient5. This means that individual cities cannot be considered “sustainable” or “resilient” without acknowledging and accounting for their dependence on ecosystems, resources, and populations from other regions around the world.2 There is therefore a need to revisit the concept of sustainability and resilience in the urban context. Here I try to contribute to more clarity around the concepts, discuss common problems with misinterpretations, and offer some solutions and reflect on difficulties that remain when applying these concepts in urban development.
Problem I. Resilience and sustainability—what is the difference?
How are the two concepts of resilience and sustainability related? Do they mean approximately the same thing, or are they distinctly different and can misunderstandings lead to undesired outcomes?
Currently the two concepts are too often used interchangeably.4 Resilience may now be more frequently in use, meaning what we perhaps ten years ago meant by the concept sustainable development. More clarity is definitely needed here. The classic definition of sustainable development focuses on how to manage current resources in a way that guarantees the welfare of current and future generations, while resilience on the other hand addresses the capacity of a system to change in order to maintain the same identity (Table 1). While sustainable development is inherently normative and positive, this may not necessarily be true for the resilience concept. The desirability of specified resilience (Table 1) in particular, depends on careful analysis of resilience “of what, to what, and for whom” since many examples can be found of highly resilient systems (e.g., oppressive political systems) locked into an undesirable system configuration or state with high levels of environmental inequity7.
Solution I: Resilience and sustainability complement each other where resilience is an important attribute of the system (non-normative) to meet the challenges of sustainable development (normative goal).
Problem II. Resilience: a property of a system, not of a locality
The resilience concept is frequently applied to specific locations, and numerous attempts have been made to analyze the resilience of individual cities. However, these attempts are misleading, as the city scale often is too narrow, and since resilience is an attribute of a system not of a locality.1,8 Urban inhabitants are today reliant on resources and ecosystem services—everything from food, water, and construction materials to waste assimilation—secured from locations around the world.3 To become meaningful, urban resilience therefore has to address appropriate scales, which most often would be larger than an individual city. A narrow focus on a single city is often counterproductive and may even be destructive, since building resilience in one city often may erode it somewhere else with multiple negative effects across the globe. Also, from historical accounts, we learn that while there are some individual cities that have gone into precipitous decline or actually failed and disappeared (e.g., Mayan cities), our modern era experience is that contemporary individual cities are unlikely to collapse and disappear.1 Rather, they may enter a spiral of decline, becoming non-competitive and losing their position in regional, national, and even global systems of cities. Through extensive financial and trading networks, cities have a high capacity to avoid abrupt change and collapse.
Table 1. Definition of concepts9,10
Sustainability Manage resources in a way that guarantees welfare and promotes equity of current and future generations
Resilience The capacity of a system to absorb disturbance and reorganize while undergoing change so as to still retain essentially the same function, structure, and feedbacks, and therefore identity (i.e., capacity to change in order to maintain the same identity)
General resilience The resilience of a system to all kinds of shocks, including novel ones
Specified resilience The resilience “of what, to what”; resilience of some particular part of a system, related to a particular control variable, to one or more identified kinds of shocks
Transformation The capacity to transform the stability landscape itself in order to become a different kind of system, to create a fundamentally new system when ecological, economic, or social structures make the existing system untenable
Solution II: Urban resilience analyses need to focus on cities as parts of nested, multiple-scale systems rather than discrete localities. We need to move away from using a narrow analysis of resilience of urban locations and instead analyze the larger open urban system including the impact and dependence on distant ecosystems connected through multiple teleconnections (i.e. long-distance connections often invisible)
Problem III. Resilience and transformations
When most people think of urban resilience, it is generally in the context of response to sudden impacts, such as a hazard or disaster. With the recent memories of natural disasters (e.g., hurricanes Sandy and Haiyan affecting large cities such as New York and several cities in the Philippines, and recent floods across densely populated places in Europe), there has been an enormous increased interest in the urban resilience concept. However, if we go back to the definitions in Table 1, resilience clearly goes far beyond recovery from single disturbances, and rather represents a multidisciplinary concept that explores persistence, recovery, and the adaptive and transformative capacities of interlinked social and ecological systems and subsystems.11
At a first glance, building resilience seems counterintuitive to transitions, given the definition of transformability as the capacity to transform and become a different kind of system, to create a fundamentally new system when ecological, economic, or social structures make the existing system untenable. Aren’t transitions about large-scale changes of a system, and resilience about maintaining what is? Key to understanding the role of transformability in resilience is distinguishing between specified and general resilience, and to remember that systems have multiple scale levels.9,11 The contradiction is real when discussing specified resilience at a specific scale level. But when analyzing general resilience of a nested system, transformation at lower scale levels are often necessary to maintain resilience on a larger scale. For example, numerous small scale transformations may be represented by urban planning targeting restoration of wetlands or forests, conservation of sand dunes, fresh water marshes, coral reefs, and mangroves throughout an urban landscape to provide cost-effective solutions to coastal protection instead of using conventional hard engineering solutions such as higher levees, sea walls, etc. A concrete example is the restoration of the Berlin-Tempelhof Airport into an urban green space of more than 300 hectares, resulting in a transformation of a brownfield into areas for rainwater management, enhancement of recreation, and biodiversity protection of importance for the larger Berlin Metropolitan area.12
Solution III: Strategies need to include an approach, which view multiple transformations on lower scales as necessary to maintain resilience on a larger scale.
Problem IV. Resilience, governance and urban planning
Urban planning practitioners see insights from resilience thinking as providing a new language and metaphors for the dynamics of change and new tools and methods for analysis and synthesis.13 For example, it has often been pointed out that one of the basic tenets of resilience and systems thinking is that too strong an emphasis on efficiency (maximising outputs) can erode resilience through a deliberate reduction in redundancy, where the system may become brittle due to too few links among actors. In governance, an increase in efficiency is often achieved through reduction of redundancy (degree of overlap among institutions and organizations). However, this may at the same time lead to increased vulnerability through failure to address novelties (surprises where responsibilities and mandates are unclear, e.g., related to climate change).
A resilience approach therefore confronts modes of governance based on assumptions of predictability, controllability, and efficiency with a mode based on dynamics, non-linearity, and redundancy. This is an emerging field where new, innovative means of planning that deal with urban complexity and sustaining urban ecosystem services are needed. However, resilience thinking and social-ecological theory alone can provide little guidance for prioritizing or addressing tradeoffs between different strategies. This highlights the inherently political character of urban governance.13
Solution IV: In urban planning, building resilience entails investing in multiple and alternative connections, i.e. redundancy, in governance and institutions at the local scale and at the global scale engaging in collaboration in systems of cities to create a framework that manages resource chains for sustainability through resilience. Resilience analyses can help us understand some of the true costs of sustainability (i.e., the cost of investing in redundancy and the cost of engaging in global cross-scale interactions).
The United Nations’ current proposals for Sustainable Development Goals includes proposed goal 11, on Cities and Urbanization, which states: “Make cities and human settlements inclusive, safe, resilient and sustainable”. I argue, based on this overview, that for the concepts sustainability and resilience and the proposed SDG goal to become truly relevant in a rapidly urbanizing world, the definitions and derived policies must urgently address four important issues:
- Urban sustainability and urban resilience are not the same, but they do complement each other where sustainability represent the normative goal for society and resilience a (non-normative) property of a system.
- In light of urban dependence and impacts on distant populations and ecosystems, there is an apparent danger of applying too narrow an urban scale for these types of policies. For example, building resilience in one city may lead to erosion of resilience elsewhere.1
- In urban planning, building resilience should entail investing in multiple alternative connections, i.e. investing in redundancy in governance and institutions at the local scale.
- Collaborations across a global system of cities should provide a new framework to manage resource chains for sustainability through resilience.2