What is carbon removal and how is it different from carbon avoidance?
Carbon removal is the act, whether through engineered or natural methods, of removing CO2 from the atmosphere. Some use the term ‘carbon removal’ to refer to only long-lived carbon storage solutions. But for the purposes of this discussion, we will be referring to carbon removal as the act of removing CO2 from the atmosphere.
While seemingly straightforward, it’s often confused with other climate solution mechanisms like carbon avoidance, which circumvent greenhouse gas emissions through an alternative activity, such as the use of solar over coal-powered electricity. Avoidance is also sometimes referred to as emissions reductions, which does not mean actively reducing carbon in the air, but rather reducing the amounts of new emissions created.
Patch finds the Oxford Principles to be a helpful guide for differentiating between avoidance and removal carbon credits. Under their definitions, emission avoidance and reduction credits are created by replacing fossil-fuel energy sources with renewable sources, as well as by capturing CO2 at the source (think carbon capture at a gas power station). Avoiding damage to ecosystems is also considered avoidance. Carbon removal credits, on the other hand, are defined as those generated by projects “that scrub carbon dioxide directly from the atmosphere.”
Can a carbon credit involve both removal and avoidance?
In many cases, a single carbon credit is created by considering both avoidance and removal activities. For example, a farmer participating in a regenerative agriculture program that creates carbon credits might both reduce their fertilizer usage—thus avoiding emissions of the harmful greenhouse gas nitrous oxide (N2O)—plant and maintain cover crops, resulting in increased photosynthesis (natural carbon removal).
In this case, the overall regenerative agriculture project is a blend of removal and avoidance. A single carbon credit created by this farmer would represent the net emissions impact of both of these activities. While some project developers, standard setters, and verifiers are beginning to parse out removal and avoidance credits separately, we’re still in the early days of the distinction’s availability among projects that simultaneously avoid emissions and remove carbon.
Indeed, many of the most innovative climate solutions coming to the fore do both, including soil carbon, forestry, and some concrete mineralization. That’s why Patch follows the guidance laid out by the Oxford Principles to prioritize a shift toward carbon removal—rather than working with it exclusively. Distinctions drawn between climate solutions, such as removal vs. avoidance, are seldom binary; instead they exist on a spectrum. It’s therefore critical to surface the nuance of these conversations in order to rapidly scale informed climate action.
Short-lived vs. long-lived carbon storage.
For both removal and avoidance credits, the Oxford Principles also distinguish between the length of time the carbon will be stored. Short-lived storage solutions might sequester carbon for a few decades while long-lived solutions might sequester it for millennia. Just as the Oxford Principles encourage a shift to carbon removal, they also encourage a shift from short- to long-lived storage.
Carbon Removal Solutions with Long-Term Storage Potential are the Foundation for Limiting Irreversible Climate Change. However, Carbon Avoidance is Crucial, as for every ton of greenhouse gases not emitted, we need to remove less than one ton.
Natural and Engineered Carbon Removal Methods
Natural carbon removal refers to the ways in which ecosystems—plants, land, and oceans—remove carbon from the atmosphere. Forests provide one of the most well-known natural methods of removing carbon from the atmosphere. Trees photosynthesize and absorb carbon as they grow, while forests remove about 15.6 billion tons of carbon each year. Although deforestation and wildfires reduce forests' net absorption capacity, they can still absorb about 1.5 times the total CO2 emissions of the United States. Forest management is one way humans can facilitate carbon removal from nature, alongside practices like kelp farming in oceans or regenerative agriculture.
On the other hand, engineered carbon removal methods are human-developed processes designed to convert CO2 molecules in the air into stable forms (liquid, solid, or contained gases) for later semi-permanent or permanent storage.
6 Ways to Remove Carbon from the Atmosphere
Patch organizes carbon removal methods into six categories based on the approach of carbon removal. Within each category, both natural and engineered methods of carbon removal may exist.
- Forestry
- Ocean-Related Carbon Removal
- Mineralization
- Biomass
- Land
- Direct Air Capture
Forestry includes tree planting and reforestation, as well as improving forest management (IFM), such as slow harvesting. Trees (and all plant species) naturally remove carbon from the atmosphere, and all forestry solutions to date have been nature-based.
One of the longest-lasting carbon storage methods is mineralization. Similar to the alkalinization process, mineralization relies on compounds that naturally react with CO2, converting it into a solid state. This process can be carried out on land, in a process called enhanced weathering, or below ground; both are forms of engineered carbon removal. Another form of mineralization is concrete spraying. In this process, the captured carbon is added to wet concrete, where it binds with other minerals and is isolated. This process also enhances the strength of the concrete, making it an attractive option for the industry that emits 8% of global carbon emissions.
One of the longest-lasting carbon storage methods is mineralization. Similar to the alkalinization process, mineralization relies on compounds that naturally react with CO2, converting it into a solid state. This process can be carried out on land, in a process called enhanced weathering, or below ground; both are forms of engineered carbon removal. Another form of mineralization is concrete spraying. In this process, the captured carbon is added to wet concrete, where it binds with other minerals and is isolated. This process also enhances the strength of the concrete, making it an attractive option for the industry that emits 8% of global carbon emissions.
Biomass is any organic matter (i.e., plants and animals)—all of which have a high carbon content. While some groups define biomass as a mitigation measure, carbon removal through biomass refers to how this material can be converted into long-term carbon storage solutions, including burial, bioenergy with carbon capture and storage (BECCS), bio-oil, or biochar.
Biochar is similar to charcoal, except it is burned at much higher temperatures and is often used for agricultural applications rather than cooking. It is also made from agricultural by-products like corn husks, instead of only wood like charcoal. It is a porous, fine, black material containing stable carbon, which can be used to enrich the soil while isolating carbon.
While BECCS is engineered, biochar clearly does not fit the nature/engineered divide as it relies on both human and natural processes. As an added benefit, the production of biochar generates heat, which many producers use to warm local villages or carry out agricultural activities.
While biochar is related to agriculture and land, direct carbon removal methods related to land also exist. These include regenerative grazing, regenerative agriculture, and land restoration. Some analyses show that regenerative agriculture, including the use of cover crops and reduced soil tilling, helps improve productivity, reduces carbon emissions from the process, and isolates carbon from the atmosphere.
Direct air capture (DAC) seems to be the most futuristic carbon removal method. In this process, air is moved through a system using liquids or solid-state filters to separate CO2. It can then be isolated or used to replace fossil fuels—though this would return it to the atmosphere. DAC is considered a promising pioneering technology.
Finding the Right Solution
While these comparisons are helpful, it turns out that turning off the tap and opening the greenhouse windows may be more challenging than it seems.
Nature-based solutions offer immediate actions to reduce carbon emissions and often provide additional benefits to ecosystems, but on their own, they cannot save us from the climate catastrophe. Furthermore, the land area needed for nature-based solutions alone would have to sacrifice valuable terrain required for food production and livelihoods.
Meanwhile, "frontier solutions" are engineered solutions designed to offer long-term carbon removal and isolation capabilities, but they are still in the early stages of development as they await investment to reach scale. Like solar energy, they start as an expensive technology before making a significant impact on our overall carbon emissions, with costs decreasing as supply increases. Currently, tree planting may actually be cheaper, but air capture technologies could provide more efficient carbon capture at a lower cost as they scale up.
Both nature-based and engineered solutions have value and will be necessary to achieve global climate goals. However, advanced technologies often have the greatest impact for those who want to scale up long-term carbon removal solutions.
About the Author:- Robert Ralph is the Partnerships Lead at Patch, working closely with both traditional and pioneering project developers who use Patch to ensure their success in the carbon market. Robert brings extensive operational and strategic experience from his time at Oliver Wyman and IESE Business School, where he built development strategies and implemented effective solutions for the most successful Fortune 500 companies and early-stage startups.
Sources patch.io , author: Robert Ralph