Biochar may now be better for Carbon Capture, but it's not 'black gold'

Researchers have found new ways to make biochar better at capturing CO₂. But the wider story of biochar and climate change is more complicated than headlines tend to suggest.

Biochar is a carbon-rich form of charcoal.

Biochar developments have been genuinely interesting scientifically, but have been hampered with big carbon capture claims, which have been pulled into question. We explore the recent research, and see whether there may be some caveats worth considering to get a balanced picture on this.

Research progress

Scientists at Shenyang Agricultural University have published a review in Carbon Research looking at how biochar can be engineered to absorb CO₂ more effectively. Biochar is made by heating organic waste, such as crop residues, wood scraps, or sewage sludge, at high temperatures with little oxygen. The result is a carbon-rich solid that can hold gases within its porous structure.

The researchers found that tweaking biochar's chemistry, specifically by adding elements like nitrogen and sulphur into its structure during production, significantly improves how well it captures CO₂. Tiny pores within the material, smaller than a nanometre across, are particularly effective because they match the size of CO₂ molecules almost exactly. The team also identified machine learning as a useful tool for designing better biochar materials more quickly.

The appeal is clear. Biochar is made from waste, costs relatively little to produce, and avoids many of the drawbacks of more complex carbon capture materials.

Taking a balanced view on the excitement behind biochar

The review itself acknowledges that most of this work is still at laboratory stage. At this stage, it can be easy to get over-excited, and that may be a trend across the biochar network. Desmog criticises how offset credit schemes, marketing protocols and investment tended to come before the sciences was settled. It even held the slogan 'black gold', as if it is a magic ticket.

Demonstrating that a material captures CO₂ in a controlled experiment is meaningfully different from demonstrating it works reliably, affordably, and repeatedly in real-world conditions. Energy costs, long-term durability, and full lifecycle emissions have not been consistently measured or independently verified across the field.

Some may argue there remains a definitional problem. Researchers have pointed out that biochar is not really one thing at all. Its properties vary so widely depending on what it is made from, and how it is produced that drawing firm conclusions across different studies is genuinely difficult. Engineered variants only add more uncertainty to the debate.

None of this makes the underlying science less interesting and potentially useful for its implementation for carbon capture. But Desmog may have a point that its claims have been over-hyped.

Industry Outlook

Engineered biochar is one of the quickly developing area of carbon capture research. Progress is real, but the field still lacks standardised testing and independent lifecycle data, particularly in a real-world context. But that is an issue faced across so many lab-based experiements and developments.

References:

Biochar 101: Climate Savior or False Hope? desmog (accessed May 2026)

Li, X., Li, X., Zhang, C. et al. Recent advances in the development of engineered biochar for CO₂ adsorption: Research on heteroatom-doped biochar. Carbon Res. 5, 26 (2026). https://doi.org/10.1007/s44246-026-00264-6