Can biochar carbon removal avoid the credibility problems of carbon offsets?

Can biochar be certified and verified in a way that offsets cannot?

Yes, biochar has a built-in credibility advantage because it is a physical material that can be measured, tracked, and verified after it is produced. A 2021 review of industrial biochar systems notes that carbon removal services via biochar are currently offered through robust marketplaces that require extensive certification, verification, and monitoring, which adds an element of credibility and authenticity [1]. This contrasts with many carbon offsets that are based on avoided emissions or hypothetical future sequestration (like forest preservation), which are harder to verify and have been widely criticized for overcounting. The same review estimates biochar can sequester 0.3–2 gigatons of CO₂ per year by 2050, with current market fees of 52–131 British pounds per ton CO₂ — a realistic price range that suggests the technology is deployable at scale [1].

However, biochar's credibility is not automatic. A 2023 study comparing 21 different biochar samples found that carbon stability — how long the carbon stays locked up — depends primarily on the type of feedstock used, not just the production method [3]. Biochars with a hydrogen-to-organic-carbon ratio (H:Corg) below 0.4 were deemed to have lower carbon stability when assessed by multiple methods, and the widely used H:Corg indicator itself provides conservative results because it is based on limited incubation experiments [3]. This means that even with certification, the actual climate benefit of a given batch of biochar can vary, and the standard tests may not capture that variation accurately. The study recommends that additional incubation and modeling data be considered to increase confidence in carbon stability results that have major implications for carbon credits [3].

Even if biochar is credible, will anyone pay for it?

The biggest threat to biochar's credibility as a solution is not technical but economic: people may not be willing to pay enough for carbon removal to make the market work. A 2022 field study of 63,520 actual airline bookings found that the median willingness to pay to voluntarily offset a ton of CO₂ from flight emissions was zero, and the mean was only about 1 euro [2]. This real-world revealed preference — what people actually did, not what they said in a survey — dramatically falls short of current offset prices, including biochar's price range of 52–131 GBP per ton [1]. The study's authors conclude that voluntary offsetting schemes currently do not very successfully internalize the cost of emissions [2].

This finding is reinforced by a 2021 analysis of the carbon offset market's underlying psychology, which argues that offsetting is sustained by a kind of collective fantasy — practitioners and buyers disavow its problems and trust in an authority (the 'Other') to make it work, rather than confronting its failures [5]. Biochar's physical verifiability could break that cycle of disavowal, but only if buyers are actually willing to pay the real cost. Without mandatory carbon pricing or strong regulatory demand, even a credible biochar credit may struggle to find a market. The 2021 review notes that biochar eligibility is highly dependent on feedstock and processing conditions, and process optimization is imperative to meet application-specific requirements and environmental regulations [1] — meaning that producing truly credible biochar requires investment that the current voluntary market may not support.

How does biochar compare to other carbon removal methods like seaweed or forestry?

Biochar has a distinct advantage over many other proposed carbon removal methods because its carbon storage is relatively straightforward to verify, whereas other methods face fundamental scientific hurdles. For example, a 2023 paper on using seaweeds for carbon removal explains that to claim carbon dioxide removal (CDR), you must prove that the CO₂ drawn down from the atmosphere is actually sequestered for more than 100 years — and for seaweeds, this requires quantifying air-sea CO₂ equilibrium, a process that operates on timescales of weeks to years and is extremely difficult to verify [4]. The paper states that current seaweed carbon storage pools (like biomass and organic carbon in sediments) do not equate to CDR unless the amount of CO₂ removed from the atmosphere can be quantified and verified [4]. Biochar, by contrast, involves converting biomass into a stable solid that can be buried or added to soil, where its carbon content can be measured directly.

Forestry offsets, another common type, have been criticized for issues like leakage (deforestation moves elsewhere), non-permanence (trees can burn or be cut down), and additionality (would the forest have been protected anyway?). Biochar avoids many of these problems because the carbon is chemically converted into a form that resists decomposition for centuries, and the removal happens at the point of production, not over decades of tree growth. However, as noted in the 2023 stability study, even biochar's permanence is not guaranteed — it depends on feedstock and production conditions, and current testing methods may not be reliable enough to guarantee 100-year storage [3]. So while biochar is more credible than many alternatives, it is not a silver bullet; it requires rigorous, ongoing quality control.

About These Sources

This answer is built on 5 peer-reviewed studies — published from 2021 to 2023, 4 in Q1 journals, collectively cited 432 times — selected as the most relevant from 5 studies that passed quality screening, drawn from 37 papers retrieved from a database of over 500 million.

Sources used in this answer

Related research questions