Why does verification accuracy matter for carbon removal markets?
Carbon removal needs to scale massively—estimates suggest 0.3 to 2 billion tons of CO₂ per year from biochar alone by 2050 [2]. To attract the billions of dollars needed, carbon markets (both voluntary and compliance) must trust that a ton of CO₂ removed is really removed and stays removed. If verification is weak, buyers won't pay, and the whole system fails. That's why the question of accuracy is central: markets depend on credible, measurable results.
Biochar: a method where verification is already accurate enough for markets
Biochar—charcoal made from plant matter and buried in soil—is one of the most advanced durable carbon removal methods. Commercial biochar markets already require extensive certification, verification, and monitoring, which adds credibility and authenticity [2]. The fees for biochar carbon removal range from 52 to 131 British pounds per ton of CO₂, showing that buyers are willing to pay for verified credits [2]. This system works because biochar's carbon stability can be measured and its permanence improved. For example, a global meta-analysis found that biochar reduces soil erosion by 16% on average, and in Mediterranean vineyards, it cut erosion by up to 65% [1]. Less erosion means the carbon stays in the soil longer, directly addressing the 'durability' concern. The same study showed biochar increased soil organic carbon by 85% with a 4% amendment rate, which is a measurable, verifiable outcome [1]. So for biochar, the answer is yes—verification is accurate enough for markets to function.
Ocean alkalinity enhancement: a harder case for verification
Ocean alkalinity enhancement (OAE) involves adding alkaline minerals to seawater to increase its ability to absorb CO₂ from the air. But verifying how much CO₂ is actually removed is much trickier. The ocean is turbulent and energetic, and the added alkalinity gets diluted to levels that are undetectable above natural background variability within months [4]. Because CO₂ equilibration between ocean and atmosphere takes months or longer, you can't just measure the change in the water and know the result. The paper on OAE monitoring states plainly that 'comprehensive quantification of carbon removal via OAE will be impossible through observational methods alone'—models are required [4]. This doesn't mean OAE can't work, but it means current verification methods are not yet accurate enough for markets without heavy reliance on computer simulations. The paper recommends that early-stage research focus on comprehensive, reproducible, and transparent monitoring to build the foundation for future markets [4].
What's missing for markets to fully trust durable carbon removal?
Even where verification methods exist, the broader market infrastructure is still developing. Currently, carbon dioxide removal (CDR) projects make up only a small fraction of the voluntary carbon market compared to emission reduction projects [3]. For CDR to scale, it needs to be integrated into compliance markets (like those under the Paris Agreement), and high-quality CDR must be clearly distinguished from other mitigation outcomes [3]. Another gap is sustainability: a review of 34 globally registered carbon standards found that none include sustainability metrics (like the UN Sustainable Development Goals) in their monitoring, reporting, and verification protocols [5]. Only one standard even requires consideration of SDGs during project design [5]. This means that even if carbon removal is accurately verified, the broader social and environmental impacts are not being tracked, which could undermine public trust and market acceptance. So the answer is nuanced: for some methods like biochar, verification is accurate enough now; for others like OAE, it's not yet; and across all methods, the market frameworks need to mature to ensure credibility.
About These Sources
This answer is built on 5 peer-reviewed studies — published from 2021 to 2026, 3 from 2024 or later, 2 in Q1 journals, collectively cited 228 times — selected as the most relevant from 5 studies that passed quality screening, drawn from 38 papers retrieved from a database of over 500 million.
Sources used in this answer
Biochar for durable carbon removal: soil erosion reduction as a key mechanism
A global meta-analysis found biochar reduces runoff by 25% and soil erosion by 16% on average; in Mediterranean vineyards, erosion was cut by up to 65% and soil organic carbon increased by 85% with 4% biochar amendment, showing that erosion reduction is a key mechanism supporting carbon durability.
Industrial biochar systems for atmospheric carbon removal: a review
Biochar systems can sequester an estimated 0.3–2 Gt CO₂ per year by 2050; current carbon removal fees for biochar range from 52 to 131 GBP per ton CO₂, and commercial markets already require extensive certification, verification, and monitoring.
Carbon markets for carbon dioxide removal
CDR projects currently make up only a small fraction of the voluntary carbon market; integrating CDR into compliance markets and clearly distinguishing high-quality CDR from other mitigation outcomes is crucial for scaling.
Monitoring, reporting, and verification for ocean alkalinity enhancement
For ocean alkalinity enhancement, comprehensive quantification of carbon removal is impossible through observation alone because added alkalinity gets diluted below detectable levels; numerical models validated against data are required for monitoring, reporting, and verification.
Alignment of Sustainable Development Goals in the Voluntary Carbon Market: Socio-ecological benefits and barriers for achieving climate goals and net zero
Of 34 globally registered carbon standards claiming to address UN Sustainable Development Goals, none include sustainability parameters in their MRV protocols for CDR technologies; only one standard requires consideration of SDGs during project design.