BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More has emerged as a promising technology for carbon dioxide removal (CDR) because it transforms easily decomposed (“labile”) carbon into a long-lived, stable (“recalcitrant”) form for storage in soils or materials. Its resistance to degradation allows it to function as a durable carbon sink with mean residence times ranging from hundreds to thousands of years, offering permanent carbon removal on human timescales. Biochar’s stability is typically determined by its level of carbonation, reflected in a lower elemental hydrogen-to-carbon ( H/Corg​) ratio (below 0.7 for high durability) or the temperature at which it was produced. Beyond climate mitigation, biochar offers co-benefits such as enhancing water retention, improving nutrient use efficiencyNutrient use efficiency refers to how effectively plants can take up and utilize nutrients from the soil. Biochar can improve nutrient use efficiency by enhancing nutrient availability and retention in the soil.   More, and reducing N2​O emissions in agriculture.

The challenge lies in biochar’s versatility, which allows its carbon benefits to be recognized across multiple, often overlapping, policy frameworks, creating a risk of multiple recognition that can undermine climate integrity. This includes the possibility of double crediting (unintentional multiple recognition) or even double counting (counting the same reduction towards the same target), which can exaggerate perceived climate progress.

A critical area of overlap is when biochar is applied to agricultural soil that is also used for biofuel feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More cultivation, potentially generating credit under two separate systems. Consider a hypothetical scenario (Case 1) where a batch of 1,000 tonnes of 80% carbon biochar is produced and sold to a farm supplying rapeseed for biodiesel. The carbon removal crediting scheme uses the permanence function from Woolf et al. (2021), resulting in a 0.71 permanence coefficient for the biochar used at the farm. This allows the biochar producer to generate 2,083 tonnes of CO2​ removal credits on the voluntary carbon market.

In parallel, the farmer is eligible to claim an esca​ credit (“soil carbon accumulation via improved agricultural management”) under the EU’s Renewable Energy Directive (RED III) by measuring soil carbon change. After five years, the soil measurement identifies an increase of 5 tonnes of soil carbon per hectare over 100 hectares, leading to an esca​ credit for the biofuel worth 1,080 tonnes of CO2​. The total recognized benefit across both frameworks is 3,163 tonnes of CO2​. This total exceeds the 2,900 tonnes of total carbon (recalcitrant and labile) stored in the biochar at application by 8%. Up to 1,080 tonnes of CO2​ benefits could be seen as double credited, as the soil carbon measurement used for esca​ cannot distinguish biochar-derived carbon from other soil carbon pools.

Another risk is that the climate benefit of biochar can be entirely offset by unsustainable feedstock sourcing (Case 3). Producing 234 tonnes of durable CO2​ removal credits from clear-cutting 4 hectares of forest without guaranteed regrowth would cause an associated land use change emission of 844 tonnes of CO2​—nearly four times the removal benefit—resulting in a net carbon increase. Existing standards attempt to prevent this by mandating requirements for biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More sourcing and forest regeneration.

To manage the market’s expansion and mitigate these risks, the following recommendations are crucial: Transparent Recognition of all opportunities for multiple benefits, ensuring they align with climate goals. Chain of Custody Measures should be implemented to track biochar from feedstock through production to end-use, enabling cross-checking of claims across markets. Finally, Post-Application Monitoring is essential for long-term impact assessment, refining permanence estimates, and ensuring the delivery of climate and ecological benefits.

Source: Phillips, J., Sandford, C., & Malins, C. (2025). Biochar: accounting for carbon benefits of production and use. Cerulogy.