Not all biochar is created equal: research needs more clarity on carbon markets and agriculture

A new study highlights serious misunderstandings about how biochar is used to fight climate change and improve soil, warning that oversimplified accounts could undermine scientific progress and carbon markets.

Biochar, a charcoal-like substance produced from organic waste, has received global attention as a promising tool for removing carbon dioxide from the atmosphere while improving soil health. But now researchers say these two benefits are often mistakenly treated as one.

In a new perspective published by Biocharscientists from Bangor University argue that carbon storage and soil benefits are very different functions of biochar, and improving one often reduces the other.

“Not all species are created equal,” said lead author Robert W. Brown. “We need to clarify what biochar is designed to do, whether it’s sequestering carbon over hundreds of years or improving soil quality in the short term.”

Biochar is produced by heating biomass such as crop residues or wood under low oxygen conditions. The temperature and raw materials used during production strongly influence the final properties of biochar. High-temperature biochar tends to be chemically stable, meaning it can store carbon in soil for hundreds to thousands of years. This makes them attractive for carbon removal strategies aimed at reducing climate change.

However, this stability comes at a cost. As the production temperature increases, biochar loses many of the surface active groups that help it interact with the soil. These functional groups are important for storing nutrients, holding water, and binding waste.

On the other hand, biochars produced at low temperatures keep these areas efficient, making them better suited for improving soil quality and reducing pollution. But these biochars degrade quickly, reducing their long-term carbon storage capacity.

This creates a natural exchange. Biochar designed for high carbon storage may provide limited agricultural benefits, while biochar developed for soil improvement may not store carbon for long.

Researchers warn that failure to distinguish between these activities can lead to misleading claims, especially in carbon credit markets. Biochar currently plays a major role in voluntary carbon markets, accounting for a large proportion of global carbon credits. However many studies and projects do not clearly report important properties such as manufacturing conditions or chemical composition.

Without this information, it becomes difficult to assess how long the carbon will be stored or what other environmental benefits can be expected.

The study also highlights that the success of biochar depends a lot on where it is used. Degraded or tropical soils often show significant improvements in crop production, while fertile soils in warmer climates may see little benefit. This difference also complicates efforts to integrate biochar performance.

Encouragingly, researchers note that alternatives can help bridge the gap between sustainability and performance. For example, mixing biochar with compost, fertilizers, or beneficial microorganisms can improve its interaction with the soil while maintaining its stability.

However, these methods generate additional costs and problems, and their results depend on the local conditions.

The authors call for a shift in what they describe as “biochar design,” where materials are designed for specific applications rather than expected to provide all benefits at once.

“Clear communication and good reporting are key,” Brown said. “If we want biochar to play a credible role in climate mitigation and sustainable agriculture, we must match the right materials with the right goals.”

As interest in carbon removal technologies grows, the study highlights the importance of transparency and accuracy. Recognizing that biochar is not a one-size-fits-all solution can help ensure that climate and agricultural goals are successfully met.

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Reference Journal: Brown, RW, Chadwick, DR & Jones, DL Unraveling the paradox of biochar carbon stability and its soil benefits. Biochar 867 (2026).

https://doi.org/10.1007/s42773-026-00581-4

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About Biochar

Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, agronomy, environmental science, and materials science. Emphasizes basic studies on biochar production, processing and applications – such as bioenergy, environmental remediation, soil improvement, climate mitigation, water treatment and performance evaluation. This journal serves as an innovative and professional platform for global researchers to share developments in this rapidly growing field.

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