How Boulder is creating a path for cities to scale up carbon sequestration

The city’s senior policy adviser for climate, sustainability, and resilience explains how it’s using its resources to find natural ways to remove carbon from the atmosphere and embed it in city owned land.

How Boulder is creating a path for cities to scale up carbon sequestration
[Source Photo: MattGush/iStock]

The focus of climate action, until recently, has been almost exclusively on strategies to reduce carbon emissions. This is understandable given that we’ve got a little more than 10 years to halve global greenhouse gas emissions if we want the planet to remain habitable. A focus on reduction, thus, remains critical.


Yet global emissions continue to grow. Diversifying our focus is, thus, essential. Not only must we be in the business of reducing carbon, we need to be in the business of capturing and sequestering it. An extensive amount of it—and fast.

There are two primary approaches to drawing carbon out of the atmosphere.

The first set depends on large-scale technological strategies that range from shooting reflective mirrors into space to building massive carbon sucking fan banks that pull carbon from the air.

The second set focuses on working with living systems that have spent millions of years perfecting carbon capture and utilization. To date these “natural climate solutions” have focused primarily on forestry or agricultural land uses. While this makes carbon capture accounting easier to quantify, it potentially overlooks the vital role carbon plays in all living systems, including urban landscapes.

We’re exploring the latter of these two. Why? Because these nature-based solutions also flip the conventional view of the climate problem on its head. Carbon is no longer the problem to be eradicated but instead the resource to be captured.


We’re interested in taking carbon from where it is not useful (the atmosphere) and putting it where it enhances life-sustaining capacities. That means we’re putting carbon back into vegetation (with trees/shade), back into soils (for healthier food, increased water holding capacity, and enhanced biodiversity), and back into oceans (for increased sea life). Stabilizing the climate becomes a co-benefit.

We’re so focused on these natural solutions to carbon that we—with the cities of Boulder and San Francisco taking the lead—recently launched the Urban Drawdown Initiative (UDI) to help cities “drawdown” carbon, pulling it out of the air and putting it back into vegetation, soil, and sea life.

Why are cities doing this?

1: Cities own land

Many cities control or influence tens to hundreds of thousands of acres within and around their boundaries. In Boulder and Boulder County, Colorado, for example, the combined, owned, open space comprises more than 75,000 acres, including almost a third of the agricultural holdings in the county. That’s a lot of land to work with to draw down carbon. The city and county have since launched extensive research and field trials of soil-based carbon drawdown, hoping to replicate successful approaches on other public and private lands.

[Source Photo: Jared Erondu/Unsplash]
San Francisco, for example, has collected over two million tons of organics and produced over 700,000 tons of carbon-absorbing compost, and they, too, have external natural resources. The city owns rangeland in its watershed and power and water rights-of-way that are suitable for treatment with compost to achieve additional sequestration.


In fact, most cities own land that has unexplored carbon drawdown potential. In cities like Stockholm, Helsinki, and Amsterdam, city planners are linking local biomass resources to novel community-based bioenergy and biochar systems that can provide both renewable thermal energy and biochar, which is a high-value sequestration resource. More exploration is essential here. The potential is vast.

2: Cities influence markets

Cities have the capacity to influence new markets for carbon drawdown. For example, Minneapolis is developing accounting procedures to value carbon as part of the city budgeting process. This could create significant investment resources for carbon drawdown activity, both within and adjacent to the city. Other cities should consider something similar. This is how we’ll create a marketplace for these kinds of high-value, nature-based solutions.

3: Cities are a climate nexus

Cities are realizing that carbon drawdown must now become a major focus of climate action, which opens huge opportunities for business and civic participation. Vancouver, Portland, and other CNCA cities have featured carbon drawdown as a new focus area of their updated climate action plans, which opens the municipal doors to more diverse constituent collaboration.

But cities are just the starting point and an important nexus for further collaboration. Rapid scale-up of carbon drawdown will depend on integrated policy development from the local to national levels. Effective collaboration among cities, regional governments, and states could dramatically accelerate carbon drawdown implementation, even when national leadership is lacking.

4: What’s next?

If you’re a city, state, region or local organization interested in drawing down carbon, here’s what we suggest:


First: Conduct an audit of the living systems—land-based or aquatic—that can sequester carbon in ways that enhance ecological, social, and economic well-being.

Second: Identify material resources that are aggregated in the urban area—organic materials, water, biomass—that can be utilized to catalyze or augment drawdown actions.

Third: Explore how to utilize the concentration of financial capital in the community to support and expand equitable and regenerative carbon drawdown.

Fourth: Leverage the political influence of the community to work collaboratively with other stakeholders—especially in rural areas—to develop laws and policies that support community-based carbon drawdown actions and economies.

Fifth: Use communications assets to grow public literacy around carbon drawdown in ways that support rapid growth of the carbon drawdown sector—locally, regionally, and nationally. We need decision-makers of all stripes talking about the solutions here.


Together, we can demonstrate the enormous potential to recarbonize living systems and help stabilize the climate. Together, we can put carbon back where it belongs. Together, we can solve this, naturally.

Brett KenCairn is the senior policy adviser for Climate, Sustainability & Resilience, City of Boulder, Colorado

Boulder is a member of the Carbon Neutral Cities Alliance, a collaboration of leading global cities cutting greenhouse gas emissions by 80% to 100% by 2050 or sooner. This is a seven-part series featuring bold actions by cities to accelerate progress toward carbon neutrality, based on CNCA’s Game Changers Report.