Metabolic Urbanism

Originally produced for ARCH: 3120- 20th Century History of Ideas with William Sherman in Fall 2019

Metabolic Urbanism: Creating Sustainable and Resilient Urban Flows

Cities are the global cores of population, main consumers of resources, and central producers of greenhouse gas (GHG) emissions. The United Nations reported that 55% of global population live in cities today, and that number will increase to 68% by 2050 (UN DESA). Billions of the world’s populations live in urban cores, meaning that resource, material, energy, and waste flows flux in and out of these central nodes, creating complex issues and externalities which contribute to climate change. The Intergovernmental Panel on Climate Change (IPCC) warned that if the average global temperature of Earth rises above 1.5°C then our world could reach a tipping point that could cause catastrophic effects on our environment, making our plant nearly uninhabitable. If the global society doesn’t begin to mediate its GHG emissions, then the warming of the planet will continue. Climate change creates more frequent and ferocious weather patterns, effecting economies, resources and human societies’ very way of life. There needs to be a focus on core global population centers where GHG emissions and consumption is high. By understanding a city less as a static entity and more of a metabolic organism, there will be a more realistic transition from traditional energy sources to sustainable ones. There also needs to be a focus on the inputs and outputs including energy, resource, material, and waste flows of the urban landscape in order to transition our current cities to more sustainable and resilient places. By applying theories of the urban metabolism and resiliency and investigating case studies, there will begin to be a clear methodology in the transition of cities energy systems. Analyzing the city as a super-organism through the lens of metabolic urbanism will drive designers, city planners, architects and policymakers to create more adaptive cyclical flows of urban input and outputs that will create cities that fight climate change and form sustainable and responsible urban cores.

Cities evolved alongside technology which shaped the way that energy cycled and flowed in and out of these urban cores. Initially, urban energy systems were typically only responsible for space heating and cooking. As urban complexity and technology evolved, the city became responsible for a slew of jobs such as space heating/cooling, lighting (indoor and outdoor), electric power for appliances, mobility services, communication, etc.

Rutter’s chart highlights the evolution of energy systems alongside population cores. Each transition of energy system marks an important moment in human history. Each transition brought an increase and intensification in energy usage and an emergence of new complexity in the organization of energy flows. With the rise of the hoe and plow, societies could harness the energy of people and animals to produce a food surplus, allowing people to settle the land (Nolan and Lenski, 140). With this food surplus from the simple energy, urban cores formed with the settlement of societies. Another pivotal energy system transition was from “biomass to coal,” as societies began to extract fossil fuels from the planet to mechanically power their cities (Rutter, 74). For the first time, people could rely on mechanical energy for transportation instead of energy from animals. This came at a cost. Coal and fossil fuels that are extracted from the Earth have a biproduct of greenhouse gas emissions.

The transition from mechanical and industrial cities to modern cities intensified the problems and externalities of the urban energy systems. As technology and scientific discoveries increased, cities could function on electricity and traditional fuel sources.

The energy demands for the domestic, commercial and industrial sectors of urban communities are now largely met by electricity and natural gas brought in through the wires and pipes of national grids. This has the advantage of physically removing many of the externalities of the energy system from the city (e.g., pollutants from combustion in electricity generation) (Rutter, 78).

The flow of energy was then more complex, being interwoven by a series of grids. While the transition from mainly coal to electricity and natural gas removed some externalities, this type of energy system, which William Sherman calls the “thermodynamic city of combustion”, continues to focus on a method and philosophy of extraction and exploitation of the planet. The “thermodynamic city” is “formed in relation to heat” with a new economy based on industry “chemically transforming materials by heat” creating harmful biproducts and transportation relying on this “combustion-driven” economy (Sherman, 97). Furthermore, these cities are “categorized and striated according to discrete functional flows”. At this point in history, the city has an energy system that pollutes and industries that are grabbing at earth’s resources hand over fist to increase production and thus profitability. Modern cities rely on the “extraction and processing of resources from natural systems to generate economic value resulting in the accumulation of waste materials and substances in the atmosphere, biosphere and hydro-sphere faster than they can be replenished or processed” (Thomson, 220). The average citizen of the modern city doesn’t have to think about where the energy, materials, or resources they use come from, or where the waste they produce goes. The striated flow of energy and waste is simply provided as an easy service by a company. Consumers are cut off from the systems of production and execration. Therefore, this takes the consumer out of the conversation on how to produce better solution to urban flows. Since the creation of the national and regional grids of electricity and power, the flow of energy is dynamic and complex behind the scenes, but from the view of the city is linear: flowing in from a source. Similarly, waste is taken out of the city. This seemingly linear movement of energy, material, resources, and waste through a city creates a multitude of issues.

In order to mediate the problems of our modern urban flows, there first needs to be a deep understanding of the systems at work and their interactions amongst them. There should be a reinvention in the way we analyze and view our cities. Metabolic urbanism is a way of viewing cities as a complex system comprised of the inputs and outputs of a system. It is defined as “the sum total of the technical and socioeconomic processes that occur in cities, resulting in growth, production of energy, and elimination of waste” (Restrepo, 217). In other words, it is a way of looking at cities as living organisms. Since the discoveries of anatomical systems, people have been making metaphorical comparisons of the body to social, economic, and urban systems.

“The metaphor that emerged from the comparison between the city and the human body was not only presented as an analogy between the spatial configuration of urban systems and human anatomy, gradually functional and structural elements of the city were involved” (Restrepo, 217). Just as the urban energy systems evolved in complexity and dynamism, so did the metaphor of metabolism with different systems. This emerging metaphor’s evolution, starting with Smith’s economic theory then Marx’s social theory, shows the differing systematic flows that it could withstand, which then led to the Japanese Metabolism Movement and Abel’s “metabolic urbanism” that analyzed the flows of the city. The term metabolic urbanism now takes the former metaphors’ factors of economic and social theories and combines it with the later urban factors of energy, resources, materials, and waste to create a fully dynamic framework that explores many facets of the city- both in social and utility systems. The metabolism of the city can show the symptoms of deep-seated issues which then can be diagnosed and remedied.

The urban system is comprised of two main categories that can be broken into two parts: the “tangible” and “intangible” systems. Most researchers that utilize a framework of metabolic urbanism only analyze the “tangible” systems, which is made up of “appropriation” (extraction of raw materials and energy from natural systems), “transformation” (production of goods and services created from materials and energy of appropriation), “circulation” (transportation and distribution of goods and services), “consumption” (use of goods and services), and “execration” (waste generated and disposal) (Restrepo, 221). These tangible interactions of metabolic urbanism can easily be seen and allow smoother data collection. The “intangible” system of interaction covers imaginaries, perceptions, laws, institutions, politics, knowledge, culture, economics traditions, and social structures in relation to energy and matter flows (Restrepo 221). Intangible systems tend to heavily affect the organization and future of the tangible systems. These two categories of subsystems can be thought of as the “ecosystem in the city” versus the “ecosystem of the city.” By having a strong understanding of the tangible flows and their trends, some of the intangible systems can utilize their power to shift and transition the tangible systems’ organization to create better cities of sustainability and resiliency.

Research on metabolic urbanism frameworks have enhanced the way we look at flows within the city. Researchers investigated Shanghai over a ten-year period of time (from 2004-2014) in order to collect data of the inputs and outputs of the city, gaining insight with the subsystems at work within one of the urban cores of China. Over the research period, the research (see diagram above) looked at tangible inputs and outputs of the city, collecting data on the local economy (GDP and population), construction sector (materials, energy, water material flow, and labor), construction activity (land use and construction investment), and environment (waste, greenhouse gas emissions, and pollutants) (Zhang 430). The results of the study found that there was an increase in population, population density, and GDP. Construction value increased over the period and the construction industry made up “4.0% of the GDP” accounting for around “9% of total employment of the city” (Zhang, 434). The study also found that the drivers of construction and development waste within the city are: population, population density, urbanization rate, consumption of materials (especially concrete), real estate investment, housing demolition and creating new buildings. Knowing the drivers to the tangible flows of an urban energy system can inform leaders in the city how to create change in the systems to manage the input and output flows in a stronger and more effective way.

The intangible flows of a city are catalysts in the transformation of tangible flows. In the Shanghai study, the social flow of government may have been the driver to the shift of resource flows. While there was an increase in material consumption due to this increase in the construction sector, there was a “decline in input density of water, energy, and land” (See data above) possibly due to a “recent sustainable development policy applied in construction ecosystem in China, which leads to considerable increase in utilization efficiency of water, energy and land” (Zhang, 437). Now that Shanghai has a catalogue of data within these different system inputs and outputs, the city can target the issues they have within the urban metabolism and make a concentrated effort to mediate these problems. The city discovered when they created new specific sustainable development policy, they could decrease the input density of several resources. With that same mentality, planners, designers, policymakers, politicians, and other urban leaders should focus their energy on resolving the issues of the city flows. The metabolic urbanism framework is a great tool to solve the city’s issues and create a more sustainable urban core.

Shanghai, as an urban core of China can further utilize the metabolic framework to improve the sustainability and social wellbeing of the city. In a similar study on inputs and outputs of urban flows in Shanghai, Han determined that the “metabolic pathways [of the city] are not sustainable given its high energy consumption” (Han, 895). After analyzing different energy densities and efficiencies of the sectors of Shanghai, Han discovered the manufacturing district is a driver for the unsustainable flows of the city. The energy intensity combined with low energy efficiency of their manufacturing sector creates a terrible mixture of unsustainability, hurting the overall sustainability of the urban metabolism. Governmental policy should shift the practices of the manufacturing district to directly affect its energy usage to create a more sustainable input and output of energy. Han suggested a shift to “encourage circular economy, cleaner production, energy management” to improve their “overall material and energy efficiency” (Han, 896). Furthermore, by improving these flows of the metabolism, different social aspects may improve. By utilizing less energy dense and more energy efficient flows within the Shanghai production sectors, the overall atmosphere of the city may improve. Improving industries’ energy flows will most likely increase the air quality, decreasing the level of smog and improve citizens’ health and wellbeing. The improvement of overall social wellbeing increases social sustainability, and can further positively affect the entire urban metabolism in sectors like the economy, public health, and other social systems.

The power of utilizing a framework of the metabolic urbanism approach is that it can take data of the flows of cities and precisely hone in on the issues of each subsystem. By using the theories of sustainability and resiliency alongside the data of the urban systems, city leaders across the fields of politics, economics, design, and planning can create real change. “Urban metabolism calculations could help to set concrete baselines or boundaries” that define what a sustainable city actually is and can “strengthen the indicators used” to rank “sustainable urban communities” (Carreon, 264). Assessments like Sustainable City Index, Smart Cities, Sustainable Cities Assessment, etc. can use the framework of the metabolic urbanism data to create real benchmarks and rankings that can be quantified and yield real change. This framework could “provide data that relates energy use with different socio-economic activities within a city” in order to assess the overall flows of both utility and social flows of a city to create more accurate and effective policies and design decisions within the urban core (Carreon, 264). Furthermore, with global agreements on climate change like the Paris Accords, the United Nations Sustainable Development Goals, and other goals/mandates, the metabolic urbanism framework can create specific mechanisms for achieving such goals within our urban cores. With mechanisms in place, these sustainability goals can be much more effective at combating the effects contributing to climate change.

The urban metabolic framework can transition energy systems to more sustainable and resilient systems. Resiliency is “a system’s ability to absorb disturbances without a regime shift” and is “the key to sustainability” (Walker, 38). While many leaders, or diverse fields, working in the realm to mediate climate change are advocating for systems of sustainability, many should also be advocating for resilient systems. A resilient system should be “adaptive cycles and “tight feedback loops” (Walker, 116). In other words, loose feedback loops tend to cut people away from the problems they cause. For example, with waste services, citizens of a city are producing a lot of waste which they pay a company to get rid of, but many people don’t actually know where exactly their waste ends up. A resilient system “has a greater capacity avoid unwelcome surprises in the face of external disturbances” and therefore have a greater capacity to “maintain and support the goods and services” that make up our lives (Walker, 37). So, creating resilient systems that make up the urban metabolism will produce a stronger overall urban system that can handle unintended disruption while still functioning. This could establish a highly effective system which would stabilize the social structures we have set up. In a resilient system, if there was an emergency error with the energy system, the system could adapt and maintain itself, meaning the severity of negative rifts across other urban subsystems would decrease. In this energy system example, typically social systems like the economic system would feel the effects of an energy crisis, but adaptive resiliency creates more stability.

Each subsystem that make up the urban metabolism should attempt to create tighter feedback loops and more adaptive cycles. For a system like energy, this would mean utilizing more renewable resources rather than importing extracted energy (i.e. fossil fuels, coal, etc.) into the city and allowing the emissions to flow out of the city. If the energy source is “regenerative” like harnessing solar power via photovoltaic panels, then there is no externality of transporting the energy to the city like there is with oil or coal since the energy comes from within the city (Thomson, 224). Furthermore, these renewable energy sources don’t create harmful GHG emissions. With an urban flow like waste, the system can become more “regenerative” and cyclical by utilizing “nutrient recycling” and upscaling waste into different systems like turning it into energy (Thomson, 225). It is pivotal to consider in what way energy systems interact with one another and how energy transformations are made. If each energy flow that made up the urban metabolism was more adaptive and cyclical, like an ecosystem of flows that interact with one another, the entire urban system would be more sustainable, and with the right design, can be more resilient.

A variety of global challenges are rooted in our urban cores. These issues include rapid population growth, increased consumption patterns, resource scarcity, biodiversity loss, social inequity, and most importantly climate change (which has links to many other intertwined issues in itself). A failure to shift current global patterns will cause catastrophic issues to our planet and the societies that inhabit it. By focusing on cities, the core centers of global population and the main drivers of consumption, we can mediate some of the root causes that are contributing to climate¬ change. In order to begin this seemingly overwhelming task, there needs to be a reimagination of how we view the city. Instead of seeing a linear flow of energy, resources etc. across a static entity, we should view the city as a metabolic organism that fluxes and transforms in a dynamic complexity. The city is an everchanging creature, teaming with flows and intersecting systems. Metabolic urbanism is a framework that can analyze inputs and outputs of a city, analyzing material, resource, energy, and waste flows, as well as social structures, institutions, information and other ‘intangible’ systems that interact to create the composition of the city. For a city like Shanghai, this means researchers can analyze energy exhausting sectors and practices like the manufacturing sector, and directly create policy which limits the density of energy input allowed and cap the amount of emissions produced from these industries. After this transformation of energy flow, Shanghai should push their energy systems further, implementing more cyclical flows and figuring out how to utilize their emissions and wastes in a way that helps their overall system, like the way Sweden uses machines that convert waste and garbage energy via heat. This example is obviously a short-term transition (as that system still has emissions). The framework and data of the urban metabolism can catalyze and provoke more diverse technologies, policies, and decisions.

The metaphor of the living body in application to the city can produce better ways of dealing with complex issues of urban cores. While inputs/outputs like the flows of energy systems may not seem to directly effect social flows, by treating the city as a whole metabolism, the interconnections of flows are clearer. A city like Shanghai, which has China’s communist government, can be affected much quicker with the swiftness of authoritarian rule that puts policy into place much faster than a city like New York City. While both of these cities and their respective “intangible” systems are very different, the application of the metabolic metaphor can work in a similar way to analyze the flows of the city, how the city functions, and highlight negative symptoms that can flag deep seated issues. In addition, the means of analyzing cities are similar within this framework, and therefore the ways we compare cities can hold more weight. The metabolic framework creates a way of communicating about the ecosystem of a city and a way to analyze the city in a very specific way. This metaphor can ground other intangible characteristics of an urban core like sustainability and resiliency into more tangible, data-driven aspects to be achieved. While sustainability policies typically focus on elements of climate change accelerators, they fail to treat the system of flows as a whole. Combating climate change will require systematic shifts in main urban sectors like transportation, industry, commercial and residential. While this seems overwhelming and create the pitfalls of only focusing on one element of one sector at a time, the urban metabolism framework will empower our policymakers and designers to think more holistically to create complex infrastructural and systematic changes that actually solve dynamic issues of flows within the urban body. A megacity like Shanghai cannot begin to solve its multitude of issues without thinking about how each input/output and systematic flows affect one another, and then propose solutions that don’t create external issues to other elements of the city. Furthermore, a country’s allocation of resources, inputs, outputs, transportation, material, and other flows create a dynamic array of complex issues. Is there a system of interaction between metabolisms? Can the framework of the urban metabolism be scaled even further up to the country scale? How might thinking of a country as a metabolism catalyze change in the creation a more sustainable and resilient future?

Works Cited

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