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How can cities transition to an economy that is ‘regenerative’ & ‘circular’ by design?


By 2050 two thirds of us will live in cities, consuming 75% of the world’s natural resources, producing 50% of global waste and over 60% of greenhouse gas emissions. (ellenmacarthurfoundation,2021). What if cities, instead of being a burden on the environment, could recycle and regenerate resources? This is the promise of "circular cities" [Circular Economy in Cities]. Building a circular economy in cities can bring tremendous economic, social, and environmental benefits.

As part of the Innovate4Cities conference, our lab recently organized a panel discussion with experts focusing on three key themes for circular cities, a) Circular and sustainable urban futures by Tamara Streefland, Metabolic b) Circular economy for the built environment by David Cheshire, AECOM c) Right-sizing waste management in cities by Steve Peters, Asian Development Bank. The session was moderated by Shiva Susarla from RENERGii Asia.

In this article, we share the key takeaways from the panel discussion.

Circular Economy is a critical component for sustainability in cities

The main challenge today concerning circularity is that cities are ever-growing and expand their ecological footprints each day. Cities usually cover a small surface area but indeed use the bulk of resources on our planet. We extract a lot of resources, use them, and produce emissions and waste affecting the population, human beings, and species. Yet, we can change our economy by reimagining our cities and supply chains.

Figure 1. A vision for the city of the future (Source: Metabolic)

Some key ingredients to promote circularity in cities include:

Involving citizens. There is a growing trend to involve citizens in city development and one such way is by having a living lab in cities. A living lab is a “user-centered, open innovation ecosystem based on a systematic user co-creation approach in public-private–people partnerships, integrating research and innovation processes in real-life communities and settings," (ENOLL, 2013). Research has proven that living labs help get more insights into the policies of the city, testbed new technologies, promote experimentation, and ground these technologies on various sites within the city.

Developing inclusive strategies. Co-creating a circular strategy, working closely with local partners, and activating local knowledge networks are also critical to the transition to more circularity. This requires looking at existing programs as a starting point, focusing on neighborhood-scale projects or analyses to design city-wide goals with unique characteristics. It is also important for cities to co-create an action toolkit, looking for new ways of utilizing construction materials, or test-bedding new projects, e.g., zero waste public institutions and schools, using biomaterials to create new structures, infrastructure.

Collecting and sharing data. A good and accessible database is important as getting insights into material flows and impacts requires data. Some cities in the Netherlands are developing workflows for data collecting and mining, providing inspiration and good practices for other resourceful cites. Data from experiments conducted in a living lab can also be leveraged, and sometimes experimentation can lead to permanence by replication to other parts of the city.

What’s next for Circular Economy in the Built Environment?

The concept of circular economy brings several specific challenges to the built environment sector. We all know that the extraction of resources for buildings and infrastructure materials such as aggregates, cement, steel, aluminum, or insulation products, has a heavy toll on our planet. If we could live more 'Lego-like lives' in which we break up, reconfigure, and create new structures from old ones, we would ease the pressure on our precious resources.

Indeed, the key challenges in sustainable construction are to use renewable and recyclable materials as well as to reduce energy consumption and waste. Although we are making progress in advanced and sustainable construction practices, we are still busy demolishing buildings in cities; Sometimes even buildings that are less than 30 years old are “downcycled” from structured concrete into segregated aggregates.

To tackle these challenges, one can look at the circular economy and try to close the loops by asking “What’s next?” for different sectors, moving away from a linear economy to a circular economy.

Figure 2. Circular Economy hierarchy for building approaches. (Source: Building Revolutions, 2016, David Cheshire, RIBA Publishing)

The solutions we should be looking at for promoting circular economy in a built environment include:

  • Refurbishing buildings rather than tearing down and rebuilding. Encouraging multiple uses for each building by tweaking the interior design, either permanently or temporarily, e.g., hospital building being used as a hotel

  • Designing and building for disassembly: A lego-like approach relying on assembling of movable buildings

  • Materials Selection: Reclaiming the old building materials into a tested and usable new product. Increasing the use of biologically derived materials.

  • Digitally map resources: We need to be able to digitally map the resources in the city to create a temporal/spatial map which helps in planning resource management for buildings

How to optimize waste management in cities to achieve zero waste?

Another key challenge cities are facing with relation to the circular economy is waste management: What to do with the increase in waste due to rapid population growth and city expansion, and also rising affluence in cities?

Figure 3: Pulau Semaku landfill, Singapore (Source: IslandNation)

In Singapore, the historical response to this challenge was Pulau Semakau, also known as the ‘Garbage of Eden’, the island nation's only landfill that started operations in 1999 with a capacity of 63 million m³ within 3.5 sqkm. It currently holds the thrash of a population of 5.6 million and is expected to last until 2035 - only if Singapore manages to reduce the waste sent to this landfill by 30% by 2030. Given the land constraints faced by an island nation, Singapore exemplifies the need for better waste management and recycling to avoid severe environmental and economic consequences of rising amounts of waste.

Yet, cities are still primarily focusing on waste to landfill or at best waste to energy plants and not looking at other recycling methods. Cities need to optimize waste management by investing in fit-for-purpose technologies that are flexible in size. Another challenge is that recycling landfills may be energy-intensive itself, due to the rising cost of fuels to operate machinery or technologies to extract materials from landfills.

There are multiple ways we all can contribute to minimizing waste in cities and achieving zero waste eventually. They include,

  • Bringing change in purchasing habits, procuring decisions, having less waste to get rid off

  • Increasing use of apps to promote segregating, recycling, and upcycling

  • Redesigning of our consumer products, e.g. minimum standards imposed in products to change the delivery or consumer perceptions.

  • Forcing FMCGs (fast-moving consumer good companies) to change their delivery habits, e.g., cosmetic sachets generating huge waste issue

  • Testbedding new technology, e.g. technology to destroy persistent organic pollutants like fly ash and waste from industries.

  • Building recovery and recycling sectors for upcycling purposes rather than focusing on energy conversion from waste projects.

We thank the three panelists for sharing their experience. Here are some additional snippets from the Q & A session.

Q. Is there money to be made in the circular economy?

David: There are mechanisms to make or realistically save money in a circular economy. The main problem in the current economy is the materials and resources available are way too cheap and don’t account for externalities associated with environmental and social impacts winning those resources. Using biomaterials and less waste will generate less disposal of chemicals and nasty materials to get rid of. In terms of circular economy business models, we should be promoting leasing or pay per use of service instead of purchasing stuff – e.g., lifts, elevators.

Tamara: Yes, and spending can also be reduced by localizing industries and services. We also need to highlight other values of a circular economy, e.g., values that are not monetary/ economic such as quality of life, green spaces, health, time, etc.

Steve: There is a lot of community engagement and opportunities for people to take part to not only earn a living but also to engage with the wellness, quality of life in the societies and at the moment our models are not designed for that. There is more than money to be made in the circular economy, there is purpose, engagement, resilience in building societies, and can build something that makes life worth living.

Q. In Southeast Asia, we hear that since cities are dense, opportunities for a circular economy are abundant. Is that true, and what implications does the COVID-19 pandemic have on the sharing model?

Steve: Not true! since sometimes you just don’t have resources or space to do recycling projects. With regards to the impact of the pandemic, there has been a surge in waste from masks and significant impact from PPEs, especially when hospitals, healthcare systems got overwhelmed.

Tamara: We need to avoid burden-shifting and think about interventions like density and urban planning holistically to […] account for the entire life cycle of certain projects/materials/features. Let me take an example with green space in cities: a lot of times when we work on designs for neighborhoods or buildings, a lot of green space gets canceled at the last moment because return doesn’t go back to investors […]. There is a need for a mindset transition on creating interconnected cities and bringing nature back to cities and living and planning cities for other species to thrive as well.

David: Density is a big problem we are going to have to tackle. As you build taller, particularly, the embodied carbon goes up by having to pour a lot more concrete and reinforce the structure more to get that height. By building lots of tall buildings, we need to think about all the implications and there's a sweet spot for height versus the number of buildings. This also is part of the problem of how we generate energy in our cities. Mid-density is probably going to be better than high density.

Q. What is the role of digital technologies in the circular economy?

Tamara: It has a big role, and it should be accessible to all stakeholders and open source (allowing access to how resources flow within the city and impacts associated with them). We should also focus on activating the insights and not only just registering them.

David: The mapping of resources in cities is important. Also, materials exchange platforms are currently limited by the number of people using them - but new platform links e.g., globe chain offering through a network, corporates to charities, and ESG report back to corporates.

Steve: Building on David's answer, digital mapping technologies and digital twins are a really important developments. There is also a need for technologies that help stop greenwashing or support environmental services, e.g. platforms to help regulate products that go onto the market. Such platforms could be used to collect a fee when consumers buy a product, e.g. a new phone, that could go into the recycling costs.

Q. If you could speak in front of the COP26 delegates, what is the one recommendation you would make?

Steve: Get rid of fossil fuel subsidies in their entirety!

Tamara: Create impact frameworks for investments and measure them (get the money in for investments).

David: Give my slot to Greta =)


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