In a recent review paper published in the journal Scientifica, authors Aruna Olasekan Adekiya, Ayibanoa Lekoo Ibaba, Timothy Oyebamiji Ogunbode, and Olajire Damilola Adedokun evaluated how biochar functions as an agent of greenhouse gas mitigation. The researchers detailed that expanding human activities have driven atmospheric carbon dioxide from a preindustrial baseline of two hundred eighty parts per million up to four hundred fifteen parts per million. This aggressive accumulation of atmospheric gases alters climate conditions essential for crop productivity, causing heat stress that reduces the efficiency of carbon-fixing enzymes and damages vital plant membranes. Because agricultural soils remain a primary source of anthropogenic emissions, integrating highly stable carbon amendments into active croplands has become a necessary priority for safeguarding global food security.

The synthesized results demonstrate that biochar effectively alters soil-level gas dynamics, though the exact directional impacts vary based on the original 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 chemistry and local water regimes. For methane mitigation, laboratory and field trials show substantial success, particularly within anaerobic environments. The inclusion of bamboo and straw biochar at an application rate of two and a half percent successfully reduced methane emissions from waterlogged paddy soils by fifty-one to ninety-one percent over a forty-nine-day observation window. This reduction occurs because biochar’s highly porous structure lowers soil bulk density and improves overall aeration. The resulting increase in oxygen availability stimulates methane-consuming bacteria while simultaneously inhibiting anaerobic methane-producing archaea. Furthermore, biochar contains active quinone and carbonyl groups that act as alternative electron acceptors, allowing soil microorganisms to bypass traditional methane-producing metabolic pathways entirely.

In contrast to these uniform methane declines, biochar’s effect on carbon dioxide sequestration exhibits high variability and can trigger unintentional carbon releases. While pyrolyzed wood chips generally initiate a negative priming effect that keeps carbon securely stored in the soil for centuries, other feedstocks display volatile behaviors. Specifically, biochar manufactured from a blend of paper sludge and wheat husk induced a positive priming effect that accelerated the mineralization of native soil organic matter. This chemical and biological interaction ultimately increased soil carbon dioxide emissions by approximately twenty-five percent compared to unamended controls. This phenomenon underlines that while biochar acts as an exceptional carbon sink due to its highly aromatic molecular structure, specific material properties like volatile matterVolatile matter refers to the organic compounds that are released as gases during the pyrolysis process. These compounds can include methane, hydrogen, and carbon monoxide, which can be captured and used as fuel or further processed into other valuable products.   More and surface functional groups can alter short-term microbial respiration rates.

Similarly, the review highlighted that biochar regulates nitrous oxide emissions by improving soil physical structure and modifying nitrogen retention. Compaction and livestock trampling traditionally restrict fluid transport in agricultural land, creating severe anaerobic pockets that stimulate nitrous oxide production. Biochar application helps resolve this constraint by increasing aggregate stability and expanding water-holding capacity, which maintains optimal soil oxygen diffusion and discourages nitrous oxide formation. Additionally, biochar’s high cation exchange capacity lets it adsorb ammonium and nitrate ions directly, retaining thirty-five percent more ammonium and twenty-eight percent more nitrate to limit substrate availability for emissions-producing pathways. These multi-sector mechanisms prove that biochar holds immense potential for climate-smart agriculture, provided that field managers select feedstocks tailored to the unique physical and biological properties of their regional soil systems.

Source: Adekiya, A. O., Ibaba, A. L., Ogunbode, T. O., & Adedokun, O. D. (2026). Biochar: A sustainable solution for mitigating greenhouse gas emissions and enhancing soil productivity-A review. Scientifica, 2026, 5690423.