Structure and agency: The seeds of sustainability for 21st century cities

Andrew Rudd
UN Habitat, USA

The recently UN-adopted Sustainable Development Goals (SDGs) set out a globally unprecedented aspiration for cities. Among other aims (including inclusion, safety and resilience), SDG-11 aspires to ‘make cities and human settlements…sustainable…’ The implication, of course, is that cities are currently not very sustainable (see Figure 1). By many measures this is true; scholars have shown how many cities are exceeding the carrying and regenerative capacity of the planet. Seto et al. show that cities on average are using land less and less efficiently. While global material extraction has slowed relative to GDP, 80% of which is produced in cities, cement production is accelerating even faster than GDP. As an outcome, the IEA and UN-Habitat estimate that cities are responsible for 60-80% of energy use and 70% of greenhouse gas emissions, respectively.

Yet none of this is a fatal flaw inherent to the urban condition. Merely critiquing cities’ unsustainable throughputs is not enough, and mistaking them as parasites is even worse because it usually precipitates highly ineffective solutions (e.g., making cities less city-like). We must not retreat from the city. Cities contain within them the seeds for overcoming their negative externalities. Catalyzing such a transformation requires harnessing agglomeration advantages and tapping into the variety that compact, mixed-use cities offer.

Figure 1. Material flows analysis of the energy flow through a city, showing inputs (top tier), transformation (second tier), consumption (third tier) and sink (bottom tier); the left-hand diagram shows ‘business as usual; the right-hand diagram is the scenario for a more circular system that would help reduce emissions and costs and increase local jobs and energy security (Source: Sebastian Moffatt with approximate data provided by Professor Jinsheng Li, Tongji University, Shanghai)

None of this will passively evolve into being, so how can we achieve it? How can cities and their residents understand that their daily behavioural choices matter for global sustainability aspirations? The solution is not as superficial as increasing the efficiency of infrastructure alone or telling people to consume less. Too few cities actually provide sufficient infrastructure or incentive for their citizens to have many choices, much less truly sustainable ones. We can’t very well expect urbanites to cycle more often without safe infrastructure in place. We can’t expect motorists to drive less without alternatives in place. And we can’t expect young people to consume less energy if cities do not meet their demand for affordable, multifamily housing stock in city centers.

First we need to address two significant obstacles at the extremes of the classic sociological polarity: one related to ‘structure’ (both sociologically and spatially) and the other related to ‘agency’.

The limitations and blind spots of urban structure

Sabine Barles writes that cities’ environmental imprint often far exceeds their boundaries. The positive corollary is that many, many people are accommodated in a much smaller space than a 1:1 ratio would require. In other words, density is a good thing. Primarily, its benefits are the intensification of exchange and the potential for shared infrastructure. While the former yields substantial socioeconomic benefits, the latter yields enormous environmental ones (including lower per capita GHG emissions; see Figure 2). By contrast, if human settlements occupied the full space of their environmental imprint, there would be far less land for natural habitat. Peri-urban agricultural land would more threatened, and per capita rates of energy use and emissions would be much higher, as there wouldn’t be sufficient critical mass for shared infrastructure and people would be forced to travel even greater distances.

Figure 2
Figure 2. Sustainability advantages of agglomeration: as metropolitan region containment increases along the X axis, greenhouse gas emissions decrease along the Y axis (Source: Philipp Rode)

Those are the agglomeration advantages that cities have historically offered. Unfortunately, there is an increasing trend for cities to forfeit their traditional agglomeration advantages as they become less and less dense. Some have simply not been planned; those that have been are often premised on cheap energy, surmountable distances, low densities and private infrastructure. But the situation is not irremediable. Making our cities more sustainable is the best option, particularly if we are going to accommodate an increasing number of humans at a quality of life roughly comparable to now.

Happily, Barles does urge us to ‘stop considering cities as unbearable parasites, to see them instead as valuable pools of energy and material resources, and to measure the contribution of the development of these resources to societies that consume less matter.’ This is also relevant for the periphery of cities everywhere where per capita consumption of energy is often the highest. Even in the core there are problems, particularly in older cities whose ageing, leaking infrastructure is completely overrun. For many cities, this will be expensive to fix, not to mention retrofit. But there is also low-hanging fruit: cities everywhere are composed of a treasure trove of concentrated resource deposits that are almost completely untapped. In other words, the more compact a city the greater the potential for circularizing its linear throughput of resources.

Insufficient agency amongst too many dwellers

Andy Merrifield has proposed two kinds of cities: generative and parasitic, each defined by the qualities of the people that live in them.

Generative cities reallocate the bulk of [their] surplus and accumulated wealth, giving it back in the form of investment that benefits production and people, public infrastructure and human capital. Parasitic cities, conversely, have their wealth squandered by a non-working yet all-consuming elite; a parasitic form of urbanization, reflective of the parasitic nature of this urbanized elite, thereby ensues.

Merrifield, A. (18 June 2013). Whose City? The Parasites’, of course… [Blog post]. Retrieved from

By his measure, it is people who consume, not cities per se. And it is the wealthiest people who consume the most in all cities, particularly those in the developing world. Merrifield’s is primarily a socioeconomic paradigm, but the principles apply to the environmental dimension as well.

The challenge is how to get people to see themselves as part of the problem, including those studying environmental trends. Nairobi hosts a high concentration of international development workers, particularly in the field of urbanism and the environment. When I lived and worked there, some of us occasionally played a sort of parlour game that matched colleagues with the size of car they drove. It usually ended with a variation of one punch line (‘…and then the environmentalist says “you mean you actually practice what you preach?”’) Certainly it raises the provocative question of whether natural scientists are more inclined than social scientists to regard themselves as neutral observers rather than agents of change.

Whatever the case, most people—environmentalists included—need to give a closer look to where they live, how they get around impact and how sustainable this is relative to alternate modes of dwelling and transport. These two are critical because they responsible for some 70% of energy and emissions. The built environment directs resource flows and heavily predicts human consumption, but it cannot will itself into being. People decide how it will be configured and managed. The problem is that when the average person doesn’t see her- or himself as an agent, s/he can’t see others’ roles and responsibilities either. And that feeds back into the decisions shaping cities in the first place.

How can cities and regions build better structure and agency? Here are three inspiring, unorthodox examples of each.

Structure-based solutions: mapping, retrofitting and circularizing

Structurally, cities need to better exploit their agglomeration advantages, and in smarter, more circular ways. How can they achieve a more symbiotic relationship with their wider environments? Here are three examples: (1) understanding the impact of the built environment, (2) reconfiguring it where it is sprawling and (3) looping its metabolism where it is sufficiently dense. Cities that have not yet been built have the advantage of pursuing multiple paths simultaneously.

Documenting landscape fragmentation in Baden-Württemberg

The German state of Baden-Württemberg studied the extent to which its physical development, built-up land cover and location of other barriers (e.g., roads and railroads) had fragmented its landscape. Its findings showed that large green patches of natural habitat had been degraded and destroyed—with detrimental effects on other species that depend on relatively uninterrupted areas for mating, resource, gathering, etc—far more extensively than previously thought (see Figure 3). The culprits? Motorized vehicles, increased mobility of goods and people and dispersed settlement patterns. As an outcome of the study, the German Federal Environmental Agency proposed quantitative limits for curbing landscape fragmentation by using the standard measurement of effective mesh size (average size of green patches of land) developed by Jäger. It would only be a first step, but a virtually unprecedented one.

Figure 3
Figure 3: Study of Baden-Württemberg showing the effect of built-up land cover, including roads and railroads, on landscape fragmentation (Source: Institute of Landscape Planning and Ecology, University of Stuttgart)

Retrofitting inefficient land use in Cape Town

In 2009, the Government of the Western Cape. South Africa drafted a Provincial Spatial Development Framework that includes a settlement restructuring manual. Amongst the aims of the manual is the densification of inefficiently used urban land. Its recommendations include the infill of vacant and brownfield urban spaces as well as the intensification of dwelling units around mobility routes, transport nodes, commercial hubs and the periphery of public spaces (see Figure 4). It also provides specific guidance on subdividing large suburban plots and creating sectional titles and a wide variety of examples of how to adapt this to contextual variations. As a result, the city-region around Cape Town is beginning to tackle urban sprawl as well as correct some of the errors of well-intentioned but disconnected satellite towns that are the legacy of the apartheid era. The lessons from its retrofitting will undoubtedly be useful to low-density cities around the world that are struggling with bankruptcy, resource inefficiency and long commutes.

Figure 4
Figure 4: Methods of densification of inefficient urban land use (Source: MCA Urban and Environmental Planners)

Bringing urban metabolism full circle in Singapore

Picture 1
Figure 5: PUB Singapore’s Deputy Chief Executive Chan Yoon Kum toasting UN Deputy-Secretary-General Jan Eliasson with NEWater (Source: PUB, Singapore’s National Water Agency)

Singapore, a relatively dense city-state, has started to put the concept of circular metabolism into practice. As the island’s water provision contract with Malaysia was about to expire, Singapore explored the possibility of recycling wastewater; not just as ‘brown’ or ‘grey’ water, but as ‘blue’ water that would be drunk from the tap. Singapore’s NEWater initiative shows the sociocultural feasibility of transforming a typically end waste product into an input for consumption. It closes the loop, and people actually drink it (see Figure 5). This kind of circularization of urban metabolism will be all the more relevant in an increasingly water-scarce world.

Agency-based solutions: measuring impact, incentivizing efficiency and expanding choices

Sustainability also requires improved agency. How can we get the average person to see themself as a change agent whose choices of where to live and how to get around profoundly impact the environment? Here a few inspiring examples.

Illuminating global footprint in Catalunya

In 2003, the autonomous region of Catalunya, Spain calculated its ecological footprint with a methodology that had previously only been applied to the city of Barcelona. This territorial approach to measurement shows the effect of an entire regional consumer economy on the loss of biodiversity throughout the world (see Figure 6). It noted that there are almost no public controls to limit the pressure on biodiversity beyond national borders, nor any assessment of the impact of internal policies on ecosystems, habitats and species. As a result, it recommends instituting global responsibility (‘extraterritoriality’) within domestic policies (e.g., relating to the import of GMO soy for local meat production) and other immediate measures to change local consumption habits. In a world where it is all too easy to turn a blind eye to far-flung causes and consequences, Catalunya has inspired a new moral imperative.

Figure 5
Figure 6: The products consumed in Catalunya traced back to their places of origin and impact (Source: The Observatory on Debt in Globalisation)

Incentivizing energy efficiency in San Diego

Lack of regulation of the power grid in the US state of California has resulted in the increased frequency and severity of electricity outages. As Slate columnist Mark Joseph Stern recently put it, ‘[w]hile 90 percent of Californians ranked energy conservation as “very” or “extremely” important, and 98 percent claimed to “try to conserve energy,” virtually no one was taking the necessary steps in their own homes.’ The city of San Diego first experimented with innovative idea of using behavioural psychology to by alerting utility customers whose neighbours were using fans instead of air conditioning. Results were positive, with an immediate 6% drop in energy consumption in targeted households. Several years later the software company OPower built on these results in cities across the US to indicate on customers’ bills how their power usage compares to that of their neighbors. Better than average efficiency earns a smiley face; exceptional efficiency earns two (see Figure 7). Positive results so far suggest that conspicuous under-consumption in relatively affluent economies may well be contagious.

Figure 6
Figure 7: OPower utility bill showing how a customer’s energy consumption compares to that of their neighbour, a measure that has resulted in reduced consumption (Source: OPower)

Making sustainable choices safer in Bogotá

Picture 2
Figure 8: Mimes at the street intersections of Bogota helped inspire a behavioural shift amongst the city’s motorists, ultimately making the choice to walk much safer. (Source: Road Accident Prevention Fund)

In Bogotá, ex-Mayor Antonio Mockus hired 420 mimes to control the city’s traffic, which prior that point had seemed ungovernable (see Figure 8). The success of the mimes is that rather than enforce a law with threat of punishment, they inspired longer-term behavior change in through persuasive, performative means. By pointing out reckless driving in a humorous way, they managed to get past many drivers’ defensive exteriors and help them identify as agents whose actions had consequences but that it was fully their choice to act sustainably or not. As an outcome, by 2003 (within one decade) pedestrian fatalities had dropped by half. While this may not have directly discouraged people from driving, it incentivized sustainable alternatives to driving by making walking safer. With car ownership in cities in emerging economies accelerating precipitously, Bogota’s behavioral shift may be the most impactful model of all.

The ‘je ne sais quoi’ we need

We create cities. When they are in trouble, only we can correct and reshape them.

The settlement patterns we put in place often lock cities into a particular infrastructural system. When that system is highly inefficient it provides people with few choices but to behave parasitically. Over the last 60+ years, the US and other land-rich developed economies have built too many cities on the basis of low-density, car-centric, choice-limiting patterns. They will have to retrofit these if the divergent demands of millennials are to be met. Cape Town shows that it can be done. Where possible, however, it is better to avoid such patterns in the first place. Unfortunately in the developing world, where some 90% of urban growth is expected in next few decades, many cities are replicating these unsustainable, choice-limiting patterns.

Urban residents need to understand how the built environment limits behavior patterns as well as the trade-offs between various dwelling and commuting modalities. Once they do, they can participate more authentically in earlier stages of the planning process. This in turn can unlock a virtuous cycle of demand and supply.

Making better choices requires that choices exist in the first place. Seeing oneself as an agent makes it easier to see the limiting power of structure. In other words, better understanding the consequences of our lifestyle choices may lead us to demand more responsible choices from others, particularly those who can afford and need most to change; this in turn may lead us to demand changes in urban systems themselves. Ultimately we need to aim for cities that offer more sustainable choices. Agglomeration provides the necessary ingredients of efficiency and variety. Bourdieu provides the necessary strategy of balancing improved structure and agency. But cities may have to look to de Certeau as their real patron saint, because achieving this at a global scale will probably also require some clever, unorthodox tactics.

Andrew Rudd

Andrew Rudd is the Urban Environment Officer for UN-Habitat in New York City.

Header Image: Aerial view of informal settlements of the Cape Flats, Cape Town, South Africa.  Credit: Andrea Willmore /


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