How can our cities go on the resource diet needed?

ANALYSIS | New tools are helping local authorities adopt a ‘systems approach’ to understanding the full scope of their resource use — and to figure out efficiencies.

Shoppers throng Shanhai's Nanjing Road, 2010. (TonyV3112/Shutterstock)

Cities are the epicentres of human activity. They cover less than 2 percent of the Earth’s land surface but generate about 70 percent of gross domestic product and house more than half the human population. The importance of cities is only going to increase in coming decades as another 2.5 billion people move to urban centres.

This intense production and consumption requires huge quantities of natural resources. Cities account for more than 60 percent of global energy use, 70 percent of greenhouse-gas emissions and 70 percent of global waste. Current practices are depleting the Earth’s finite resources, changing its climate and damaging its natural ecosystems. With our planetary life-support system in the red, we need to put cities on a serious resource diet.

The New Urban Agenda adopted at the Habitat III conference held in October outlines a vision for sustainable urban development. These global guidelines, along with the related U. N. Sustainable Development Goals, recognize the need to use resources more efficiently.

The Habitat III summit included a number of sessions on resource efficiency and associated tools and initiatives. Organizations such as UNEP, UN-Habitat and the European Commission and its research centres typically led these events. The New Urban Agenda includes many references to efficiency and reduced consumption in cities.

[See: Eleven cities that are showing the way on fighting climate change]

We must now act urgently to translate words into actions. This will ease pressure on ecosystems and produce a range of co-benefits, including health, well-being and resilience.

How do we create more resource-efficient cities?

Cities use resources directly, such as burning fossil fuels for electricity and transport. However, indirect uses, such as water for growing food crops, are much wider-reaching.

It can be overwhelming to consider the resources used for all goods, processes and infrastructure in cities. Yet it is possible to measure this using a systems approach. Instead of considering components in isolation, the entire city is considered as an open system, connected to others.

This perspective ensures a much broader understanding of complex relationships between scales, resource flows, the built environment, socio-economic factors and ecological outcomes.

[See: Cities and experimentation are central to water sustainability]

There are tools that embrace a systems perspective. For example, the urban metabolism approach considers cities as ecosystems, across which flows of resources (such as energy or water) are measured. Life-cycle assessments measure resource use through the entire production, consumption and degradation process of a good or service.

These approaches have been successfully applied at various scales such as cities, neighbourhoods and buildings. This reveals that we are using more resources than shown by traditional assessment techniques (see this example on building energy efficiency regulations).

But measurement without action has no impact on the ground. How can these tools be used to transform our cities?

Recent research enables us to map the quantities of materials in buildings and predict when and where we can reuse or recycle these. Here is a map of estimated steel quantities in each building of Melbourne, Australia.

Source: authors’ own; left: Google and TerraMetrics; right: Stephan, A. and Athanassiadis, A. (In Press) Quantifying and mapping embodied environmental requirements of urban building stocks, Building and Environment

Many initiatives are targeting urban resource efficiency. The circular economy paradigm is a good example, where materials are reused, “upcycled” and recycled. It demonstrates that waste is a human concept and not an inherent property of cities. Waste does not exist in natural systems.

[See: What Melbourne learned cutting emissions from ‘1200 Buildings’]

A range of projects by the U. N. Environment Programme, the European Commission and other organizations support local resource-efficiency initiatives and encourage local governments to implement related regulations. Blogging, data visualization and disseminating research all help promote the adoption of resource-efficiency concepts.

In addition to the pioneering work of groups such as Metabolism of Cities, the uptake of open data is helping with this.

Learning from those who already live on less

Informal settlements provide interesting lessons in resource efficiency. Construction materials in these settlements are typically not very durable. However, because they are in short supply, they are constantly reused or repurposed, almost never discarded.

Other residents often reuse replaced materials, such as metal sheets, or store them for later use. This practice avoids additional resource use to produce new materials.

[See: At Habitat III, architect Aravena lobbies for ‘bamboo and mud’]

Although informal slum areas are often the focus of “upgrading“ and improvement, lessons learned in these settings can enhance material flow management and reduce waste elsewhere in cities.

Co-benefits of efficiency

Cities that are more resource-efficient tend to result in better health outcomes. For instance, encouraging walking, cycling and public transport instead of car use can reduce fossil-fuel consumption and greenhouse-gas emissions, and improve population health through increased physical activity.

Food systems that promote consumption of fresh, local produce can benefit both the environment and nutrition. Energy-efficient housing reduces energy and water use, and can improve occupants’ health at the same time.

[See: Health is a prerequisite for sustainable urban development]

Resource efficiency also can contribute to urban resilience. Nature-based solutions use relatively few non-renewable materials to increase resilience to environmental change and natural disasters. For example, a park can be designed to be flooded during storms or a tsunami, reduce the urban “heat island” effect, support urban ecosystems and provide areas for community activities, recreation and urban agriculture.

Efficiency also can ensure that redundancy — a core principle of resilience — is built into urban systems. This means resources can be repurposed in the event of an unanticipated shock or stress. For example, during the recent blackout in South Australia, a household with solar battery storage was able to maintain power for 12 hours “off grid”.

Working together for better solutions

Although these steps move cities in the right direction, more action from governments, the private sector and civil society is needed to transform our growing urban footprints.

Focusing solely on resource efficiency may neglect opportunities to generate co-benefits across sectors and will not provide robust solutions. We need to look at the entire city as a system and work together, across all disciplines, with effective and strong governance structures that support integrated policy definition and long-term implementation. If we don’t, we might simply shift a problem from one area to another, increase resource demand elsewhere, or create social divisions and tensions.

[See: Platform needed to provide scientific input on New Urban Agenda implementation, researchers say]

Strong leadership, political stability, effective institutions and awareness-raising among citizens are vital factors for success. Urban resource efficiency is critical, but it should be considered along all other pressing issues highlighted in the New Urban Agenda.

This article was originally published on The Conversation and was written by André Stephan, Postdoctoral Research Fellow, University of Melbourne; Alexei Trundle, PhD Candidate, Australian-German Climate & Energy College, University of Melbourne; Dave Kendal, Researcher, Royal Botanic Gardens Victoria (ARCUE), University of Melbourne; Hayley Henderson, PhD Candidate in Urban Planning, University of Melbourne; Hesam Kamalipour, PhD Candidate and Research Assistant in Urban Design, University of Melbourne; and Melanie Lowe, Research Fellow, McCaughey VicHealth Community Wellbeing Unit, Melbourne School of Population and Global Health, University of Melbourne. Read the original article here.

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