CDR in the city: are urban areas a ‘sleeping giant’ for carbon removals?

Carbon dioxide removal (CDR) is now no longer an option – but a necessity. The recent IPCC Synthesis report makes this crystal clear and calls on the global community to answer a pressing question: how can we scale carbon removals at speed, responsibly?

A South Pole and Bellona report for the City of Amsterdam recently demonstrated that cities have large, untapped CDR potential and provide some answers and avenues for climate action. Could urban areas be the big untapped opportunity for scaling carbon removals? According to the report, yes: cities are “sleeping giants" for carbon removal, and we must wake up with imagination, innovation and action.

Turning the oil and gas industry upside down

Imagine the inverse of the current model of emitting carbon. A world in which carbon flows seamlessly from the air, through the arteries of our global ecosystem and centres of production, to different storage destinations. Not to the atmosphere but into a storage economy. A vast network of pipelines, ships, trucks and trains, alongside a supercharged ecological infrastructure that carries CO₂ molecules from their source to sink, connecting remote corners of the globe with cities, the nuclei of society.

It is often said that the carbon removal industry needs to match the size of the oil and gas industry if humanity is to reach its climate targets. These comments refer to CO₂ volumes: a significant portion of what society emits, the carbon removal industry will have to suck back in. What the analogy also implies is the size and extent of the infrastructure system needed to realise this monumental task. Actors at all scales will be indispensable. And as both major sources of and potential sinks for CO₂, cities can become critical nodes in the emerging global carbon removal infrastructure.

The potential of urban carbon removal

Currently, carbon dioxide removal is mostly focused on solutions outside of urban centres. Large-scale afforestation, reforestation, mangrove restoration and carbon farming require huge areas of land. Meanwhile, the deployment of a technical carbon removal infrastructure is not yet part of urban city planning. This limited thinking obscures the massive potential of urban carbon removal.

Last year, the City of Amsterdam commissioned South Pole and Bellona to analyse the removal potential of the Amsterdam Metropolitan Area and the North Sea Canal Area. What we found during this high-level analysis was eye-opening. In Amsterdam alone, an annual volume of nearly 1 Mt of biogenic CO₂ could be removed via Biomass Carbon Removal and Storage (BiCRS) from biomass power generation, biogas production, waste-to-energy and wastewater treatment. This doesn't even account for all biogenic emissions in the area.

By comparison, Amsterdam currently emits ~4.5 Mt CO₂ every year. As part of its climate neutrality policy, the city's goal is to achieve a 55% reduction in emissions by 2030, and a 95% by 2050 – similar to those of other cities aiming for net zero. It expects to use removals to accelerate mitigation efforts and reach net zero. Even with our conservative estimate, there is significant potential for removals to complement deep emission reductions to ultimately make cities net negative (remove more carbon than they emit).

Reimagining cities as carbon sinks

Capturing biogenic emissions for long-term storage is just one of many CDR measures that could be implemented. A range of additional standalone solutions could add significant carbon removal volumes. Applying biochar for soil amendment in Amsterdam, for example, could result in a cumulative removal potential of 2 Mt CO₂. The biochar company Novocarbo is moving ahead with this in Germany, reimagining the role of parks in urban centres and creating 'carbon removal parks'.

Direct Air Capture (DAC) units, meanwhile, can be integrated into neighbourhoods, in addition to large-scale industrial facilities in remote locations. Carbon180, a US-based NGO focused on removals, has imagined such a distributed network of DAC units in neighbourhood parks and built into supermarkets and apartment buildings, and called for greater engagement with communities. Taking this to the next level, design firm SOM envisaged radical design changes to change entire buildings from carbon sources into carbon sinks. They refer to structures that 'consume' more carbon than they produce as Urban Sequoias. Such buildings would integrate DAC units and urban forests as part of their design and would be built using materials that absorb CO₂ during their lifetime, such as Hempcrete.

The bottom line is that urban structures can be designed in such a way that they remove carbon from the atmosphere during their lifetime. Imagination and innovation are clearly not the challenges.

It's all about the infrastructure

What we need to unlock this decentralised removal potential is a vast network of hard and soft infrastructure deeply embedded within cities' very structure. Long-term carbon storage requires dedicated carbon capture infrastructure, different modes of transportation, and the creation of a storage economy. But plant operators may not have the finances available to invest in such a network.

This is where soft infrastructure comes in. Facilitating the construction of such CO₂ collection infrastructure should be a public responsibility, similar to the city's responsibility for public infrastructure such as water and electricity, which is financed or deployed through regulated assets. Yet citizens are unlikely to agree to their municipal government taking on this innovative role until the idea of carbon removal has been properly socialised and communities have been guaranteed a guiding voice in the policymaking process.

To bridge this gap, we need to be clear-sighted about our goals and strategic approach to their delivery. To date, more than 240 cities have formally committed to net zero, according to the Net Zero Tracker, and more than 1,100 are part of the Race to Zero campaign, led by the UN Climate Change High-Level Champions. Cities have a galvanising effect on climate action by virtue of being closer to citizens than national governments: they incentivise action on the ground while stretching the boundaries of urban design, born out of the necessity of dealing with the direct consequences of climate change.

Guided by such targets, the soft infrastructure that cities bring to bear is indispensable. However, they are currently struggling to put carbon removal policies in place to deliver net zero. As with countries and companies, there remains a deep gap between cities' ambitions and actions in their pursuit of net zero. Cities urgently need to step up to this challenge by building the necessary knowledge, capacity and networks to integrate removals into their climate strategies and integrate removals in urban planning.

Carbon removal as a public good

Changing the way cities think about carbon removal can stimulate action to tackle the many barriers that remain. These include the lack of demand signals to project developers (created by the lack of CDR-specific targets and legislation), the lack of accessible transport networks, long lead times, lengthy regulatory processes, and the huge discrepancy between public acceptance and the scale and urgency of the challenge.

National governments have a responsibility to scale carbon removals, but cities are uniquely positioned to accelerate the deployment of projects and catalyse private sector action. To do so, they will need to help. Deploying the required infrastructure (both hard and soft) on the scale required will be a challenge. This mandate will only be created by treating the removal of CO₂ as a public good. Similar to waste management services, local governments should provide or promote carbon management services as an essential public service.

Cities can achieve what other systems cannot. They are motors of change and innovation, concentrating economic, political and cultural activity, with the potential to design, facilitate and implement concrete actions in direct engagement with communities in a way that national governments aren't able to do. Their unique potential to catalyse carbon removal is huge.

As a first step, we call on cities to:

1. Assess the opportunities for CDR within and around their urban environment;
2. Determine the necessary volumes of CDRs to accelerate decarbonisation and reach net zero;
3. Establish CDR-specific targets; and
4. Develop CDR-specific strategies within their climate action plans.

It's time to wake this sleeping giant! To avert the worst impacts of climate change we need to build on innovations already happening, lay the groundwork in policy and infrastructure and put our current carbon-emitting system in reverse.