How It Works

Quick Facts

Market Position

86% of durable CDR deliveries in 2024, 83% from 2020-2024 (CDR.fyi)

Carbon Removal Potential

0.5 to 2 gigatonnes of CO2 per year globally by 2050 (Fuss et al., 2018)

End uses

As soil amendment or animal feed in agriculture, or as an additive to durable construction materials

Co-Benefits

Biochar delivers a range of co-benefits, particularly in agriculture and construction.

Soil Health

Improves water and nutrient retention, boosting soil health and leading to increased crop yields of up to 42%.

Climate Resilience

Helps farmers replace expensive fertilizers, promotes more sustainable agricultural practices, and revitalizes depleted soils.

Wildfire Prevention

Removes high-risk plant material from fire-prone landscapes, significantly reducing available fuel loads and fire risks.

Energy Co-Benefits

Pyrolysis generates renewable energy (heat, electricity, or biogas).

The Science

Biochar Carbon Removal is a scientifically validated, scalable carbon removal technology that locks atmospheric CO₂ into a highly stable solid form for hundreds to thousands of years. Its durability, co-benefits, and flexibility across scales make it one of the most deployable carbon removal solutions available today.

A Time-Tested Concept Backed by Modern Science

The practice of enriching soil with carbon-rich materials dates back over 2,000 years. In the Amazon, Indigenous communities created terra preta— “black earth”—by adding charred organic matter to nutrient-poor soils. These soils remain fertile today, offering a living example of long-term carbon storage and enhanced soil health.

Modern biochar projects build on this ancient principle using controlled technologies to create a verifiable and certifiable climate benefit.

From CO₂ in the Atmosphere to Stable Carbon in the Ground

The carbon capture process begins with photosynthesis: plants absorb carbon dioxide (CO₂) from the atmosphere as they grow. This carbon is stored in plant material—referred to as biomass.

If left to decompose or burned, this biomass would return its carbon back to the atmosphere as CO₂ or methane. Biochar production intercepts this natural cycle by converting the biomass into a stable form of carbon via pyrolysis—a thermal process carried out in low-oxygen conditions at 500–700°C.

During pyrolysis, the biomass’s chemical structure changes. Volatile components are driven off, and what remains is a carbon-rich solid known as biochar. The stability of this material is due to the formation of aromatic carbon rings—molecular structures that resist microbial degradation and persist in soil or durable materials for centuries.

What Influences Biochar Quality and Stability?

Not all biochar is created equal. The type of biomass, its moisture content, and the temperature and duration of pyrolysis all influence the final product’s stability and performance.

Wood-based feedstocks, especially hardwoods, produce biochar with a higher carbon content and greater permanence.
Agricultural residues and manures offer nutrient-rich biochar but tend to have lower carbon stability.
Higher pyrolysis temperatures typically result in a greater share of recalcitrant carbon—the fraction that remains stable long-term.

Commonly used indicators to assess biochar stability are the hydrogen-to-carbon (H:C) ratio or the random reflectance of the biochar. The determination of the permanent fraction, which can be accounted as a geological sink, depends on the calculation methodologies provided by the Standards that issue the carbon removal credits.

A Solution Across Scales: From Kilns to High-Tech Pyrolysis Plants

Biochar can be produced using both low-tech and industrial-scale systems. Kon-Tiki kilns, for example, are simple open-cone structures used in decentralized settings, often by smallholder farmers. These systems utilize crop residues that would otherwise be burned—reducing emissions while improving soil health and providing benefits for the local communities.

On the other end of the spectrum, industrial pyrolysis plants offer high-throughput, controlled production. Many also recover and utilize the heat or gases produced during pyrolysis for energy—making the process more efficient and resource-positive.

Maximizing Impact: Durable vs. Non-Durable Biochar Applications

For biochar to qualify as durable carbon removal, it must be stored in a way that prevents carbon from re-entering the atmosphere.
‍
This is achieved by mixing biochar into soil or by embedding it in durable building materials such as concrete, bricks, and asphalt. In both cases, the carbon is physically and chemically stabilized.

Biochar can also be utilized in wastewater treatment, as an additive for the production of plastics, paper, and textiles or as fossil fuel replacement in metallurgic industries.

Beyond Carbon Removal: Additional Benefits of Biochar

Biochar delivers a range of co-benefits, particularly in agriculture and construction:

Soil health: Biochar improves soil structure, water retention, and nutrient availability, leading to higher crop yields and reducing fertilizer use.
Climate resilience: Biochar improves soil moisture retention, helping mitigate the effects of drought and extreme weather.
Green energy: Pyrolysis generates renewable energy (heat, electricity, or biogas)
Material innovation: When incorporated into construction materials, biochar can enhance insulation and material strength, while significantly reducing the carbon footprint of buildings.

Scientific Validation of Biochar Durability

The permanence of biochar as a carbon removal solution has been demonstrated in both laboratory and long-term field studies. When produced and applied under appropriate conditions, biochar can stabilize a large fraction of carbon for centuries to millennia.

Benchmarking Biochar Stability with Inertinite

Assessing biochar's permanence: An inertinite benchmark (Sanei et al., 2024)

‍This 2024 study introduces a stability benchmark based on inertinite—a naturally occurring, highly aromatized carbon form found in coal. It defines a random reflectance (Ro) value of 2% (Ro2%) as the threshold for quantifying the inertinite fraction of biochar: the portion expected to persist over millennia. Reflectance measures the degree of carbonization—higher values indicate greater molecular condensation and durability.

In one commercial sample, 76% of the solid carbon exceeded the Ro2% threshold—indicating dominant inertinite character and strong suitability for long-term carbon removal.

15-Year Field Evidence in Agricultural Soil

Assessment of long-lived Carbon permanence in agricultural soil: Unearthing 15-year-old biochar from long-term field experiment in vineyard (Chiaramonti et al., 2024)

‍In a 15-year vineyard trial, researchers excavated and analyzed biochar from agricultural soil. After isolating the original biochar fraction from soil-derived material, they compared it to archived samples of the original material. The inertinite and semi-inertinite shares were found to be virtually unchanged—demonstrating that biochar’s most stable carbon structures remained intact under real field conditions and qualify as permanent under CDR frameworks.

Structure Determines Durability

Molecular characterization of biochar and the relation to carbon permanence (Rudra et al., 2024)

‍A 2024 study reinforces the link between molecular structure and biochar durability. Biochar produced at higher pyrolysis temperatures exhibits increased aromaticity and structural condensation—resulting in strong resistance to microbial degradation.

The most stable samples consist predominantly of inertinite, with full random reflectance (Ro) distributions above the inertinite benchmark (Ro2%). These results align with high carbon stability and support the use of inertinite-rich biochar for long-term carbon removal.