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Creating circular cities hinges on valuing embodied carbon

From food to materials to buildings, cities host the experiences that transform embodied carbon into the stuff of life.

The junction in a city, showing a large circular road

Becoming carbon neutral by 2030 is becoming a civic moonshot of our time. Creating carbon neutral cities requires major carbon emissions reductions complemented by carbon removal — implying energy efficiency, 100 percent renewable power, more resilient and flexible grids, powering through the electrification of everything, and more. 

Circular economies will become a key complement to this decarbonization.

If the millions of metric tons of embodied carbon diffused throughout civil society are to stay in play, that process must play out in cities. Why? Because cities are where oft-punted Scope 3 emissions from consumption and the built environment come home to roost. They are also the last mile of the value chain, hosting what could be richer value creation — and re-creation.

Even as fantasies of feedstock loops begin to come true (thank you, Eastman, Unilever, Novoloop and more) and plastic waste from around the world is becoming a new favorite shoe (thank you, First Mile), it is in cities that the shortest and lowest-carbon circling cycles can be achieved. 

As the last-mile location of value creation, cities host the experiences that transform embodied carbon into the stuff of life. They are also where tastes are made, fashions are set and new norms are normalized. The sections below consider the state-of-the-art when it comes to food, materials and the built environment from the perspective of circular cities.

Tightened food loops

Wasted food is responsible for 6 percent of global greenhouse gas emissions. With about a third due to waste at home, online ordering and pre-prepared meal kits can cut waste through more right-sized food purchases.

Restaurants, too, are tightening the loop and contributing to a circular food fashion. Sustainable sourcing and labeling strategies are led by Panera’s "Cool Food" badges, Just Salad’s carbon label and Chipotle’s (confusing) "Real Foodprint." These declarations empower diners to make choices that minimize embodied carbon.

Cities are where oft-punted Scope 3 emissions from consumption and the built environment come home to roost.

Adaptive cooking is trending, as chefs find roles for normally ignored cut-aways and out-of-fashion foods and feature "Trash Pie" on the permanent menu. Throw-aways are minimized with half-portions and, in some cases, discarded prep foods are upcycled offsite and brought back to play. Finally, nonprofits such as Food Runners and platforms such as Goodr are building smart ways to scoop up unused food for the hungry, reducing greenhouse gases on the way. 

Needed next is a ramp-up of municipal composting, to take what cannot be used and return it to the soil while avoiding misplaced methane release. Indeed, food waste has become a focus of several circular city models, including Europe’s CityLoops and Baltimore’s Waste-to-Wealth. Coming further full circle, an award-winning chef wants diners to fund regenerative ag.

To super-charge all of this, the nonprofit ReFed provides an insight engine to understand food waste problems, deploy solutions and calculate the impact. We’ll need to see food waste management take its place as an essential infrastructure in the cities of the future.

Creative material moves

Seeds of a material re-visioning are also being entrepreneurially planted in cities around the world.

Although reusable containers became scary during the pandemic, single-use is no safer than professionally cleaned reuse. Dispatch Goods partnered with San Francisco restaurants to pilot reusable containers for the pandemic-prompted takeout culture. While the corporate lunch surge was its biggest pre-pandemic market (with a container return rate of 92 percent), the logistics of home collection are more challenging. Still, a reuse revolution is emerging.

In a recent study modeling cup reuse vs. recycling at urban event centers, reusables won handily as the most climate-friendly (although this is more powerful when the cup is also one-day recycled). Closed Loop Partners offers a playbook that spells out how to switch to reusable cups. 

In the fashionable world of clothing, durability is also back in style. A study by thredUP estimates that the secondhand clothing market will double in the next five years. During the pandemic, a rise of fashion resale options coincided with COVID-inspired closet-cleaning. So even as circular fashion inventories were being enriched, circling itself got easier — both for businesses (Trove, Recircled, Circular Toolbox) and for consumers (Vinted, Depop, TheRealReal). But it also got more creative. From GenZ’s craftcore culture to Isso’s upcycled classics, and from a New York street tailor to one writer’s choice to have a personal one — a reuse frame can free your mind.

In a world of the future, every ton of embodied carbon will generate a longer-lived value chain than it does today.

Also supporting the longevity of apparel is the new Higg Product Tool (a for-profit spinoff of the Sustainable Apparel Coalition). In addition to providing modules to measure the sustainability and carbon impacts of garments’ sourcing and production, the software helps to measure those of their distribution, sale, use and reuse. With a toolset so comprehensive it includes a DIY module on how to replace a product’s zipper, Higg might just double as a great handbook for local small businesses serving the value regeneration business.

Increasingly, furniture is being better freed for reuse. Feather, serving cities across the U.S., rents high-end furniture — perfect for young urban apartment dwellers who may move in the next year or two. Meanwhile, IKEA leads in designing furniture specifically for reuse, refurbishment and repair — a pattern to be aided by its delayed but now active buy-back scheme. Other companies are providing infrastructure to give back no-longer-needed furniture for reuse.

Meanwhile, Rheaply is a digital infrastructure system for managing assets of all kinds. It aims to keep the material world in circulation by connecting systems and cities to create reuse networks. It views its flagship technology as "infrastructure to increase health and wealth," helping cities to become locally productive, resource-efficient hubs.

Embodied space

Speaking of infrastructure, the soon-to-be-embodied carbon from future construction projects needs to be designed with a long-lived value chain in mind, as embodied carbon from building materials and construction account for 11 percent of global greenhouse gas (GHG) emissions.

This is beginning to be mitigated through carbon-sucking concrete and facades made of air. Decommissioned windmill blades are ending up in playgrounds and pedestrian bridges and recycled plastics are showing up in applications ranging from windows to bridges. Even new districts are emerging from the artifacts of their histories. Indeed, the circling of construction-and-demolition-waste (CDW) is key to Europe’s and Baltimore’s circular city models.

But the biggest way to maximize value in  the built environment is, well, to use it well.

Just as smart grids and sharing economies allow more value generation without more capacity, smarter use of the buildings already in play could help contain the growth of embodied carbon in our cities. While shifting use of existing building stock is not as dynamic as a demand-response contract or a shared ride, zoning to allow responsive re-configuration and re-allocation of space is a smart policy principle in a carbon-intensive built environment.

As hotels become housing and housing moonlights as hotels, so too could office towers host apartments for business travelers or more permanent residents while also securing the vitality of downtown businesses through holidays, weekends, pandemics and permanently shifted work patterns. With office vacancies at an all-time high, it’s arguably an idea whose time has come in multiple cities once we look around to assess our actual needs.  

While such approaches may sound disruptive, a thoughtful system could provide more steady revenues to landlords and ease the housing and climate crises plaguing cities and communities. At the same time, they can secure the relevance of last-mile small businesses in downtown areas and keep them in place to host the value chain and provide convenient contact points to circle back and close loops.

A Renaissance rising?

Circular experimentation and collaboration infrastructure is slowly taking shape to support the circular renaissance that we need.

Meanwhile, civic playbooks are being written around the world. Small-business toolkits are offered from Chicago and Glasgow, a share-reuse-repair practice is emerging in Vancouver and a circular cities and regions initiative (CCRI) soon will be piloted in 15 local governments across Canada. CityLoops is hosting circular city experiments in seven modest-sized cities in Europe. And the Ellen MacArthur Foundation offers a food system playbook for cities anywhere, as well as circular policy case studies from a dozen cities around the world.

In a world of the future, every ton of embodied carbon will generate a longer-lived value chain than it does today. And, someday soon, our progress must become a measurable one as well.

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