Removing carbon from the atmosphere: 6 strategies

In more direct terms for this once-upon-a-time engineering graduate: to return atmospheric carbon levels (currently 420 parts per million (ppm)) to pre-industrial levels (280 ppm), humanity will need to not only stop emitting greenhouse gasses, but also to increase the amount of carbon dioxide (CO₂) that is removed from the atmosphere. 

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 amount 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.

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