Imagine transforming yard waste, wood scraps, and farm leftovers into a material that locks carbon in the ground for centuries while enhancing soil health. This is the concept behind biochar. However, this narrative doesn’t capture the entire picture.
For over two decades, researchers, entrepreneurs, and climate advocates have championed biochar as an effective method for extracting carbon dioxide from the atmosphere. Early estimates suggested it could remove 3.4 to 6.3 billion tons of COâ‚‚ annually, a staggering potential that fueled numerous scientific studies, startup investments, and carbon credit transactions.
Yet, a new analysis published in Nature Sustainability in January 2026 advises caution. While biochar is indeed promising, the enthusiasm has outpaced the facts. Researchers caution that excessive hype could trigger a “boom-and-bust cycle” detrimental to the technology.
What Is Biochar?
Biochar is a type of charcoal, distinct from what you use for grilling. It’s produced by heating organic materials like wood chips, crop waste, or agricultural byproducts in a low-oxygen environment via pyrolysis. The outcome is a dark, porous, carbon-dense material that remains stable in soil for centuries or even millennia.
The concept draws inspiration from ancient Amazonian soils. Researchers found that the fertile “terra preta” (Portuguese for “dark earth”) of the region owed its richness to charcoal added by Indigenous peoples thousands of years ago. This charcoal persisted, continuing to enhance soil structure and fertility long after the civilization that created it had vanished.
Upon studying terra preta, scientists realized that sequestering carbon in a solid state and burying it in soil effectively removes it from the atmosphere for extended periods. Biochar seemed like a dual benefit: storing carbon and benefiting agriculture, driving further research, funding, and the emergence of new companies.
The Numbers That Raised Alarms
The issue isn’t that biochar is ineffective, but rather it hasn’t met the lofty initial expectations. Italian soil scientists Luciano Gristina and Riccardo Scalenghe detail the numbers in a Nature Sustainability analysis.
Let’s consider production. Globally, certified biochar facilities produce about 350,000 tons annually. Although this seems substantial, spread across the world’s 1.5 billion hectares of farmland, it’s minimal. The researchers noted that this production would elevate the soil surface by less than one-tenth the width of a human hair each year, highlighting the gap between current production and climate goals.
Next, consider carbon storage. Biochar’s real impact is a thousand times less than early estimates. After accounting for emissions from production, the net climate benefit is only a few hundred thousand tons of CO₂ at best, compared to the global emissions of around 36 billion tons annually.
Economics exacerbate the challenge. Studies indicate that feedstock—the raw material for biochar—can constitute up to 75% of total costs. Thus, biochar projects are only financially viable if they have access to free or very cheap biomass, or consistent income from carbon credits. Absent these, most projects are unprofitable.
In Southeast Asia, trials indicated that adding biochar to farmland resulted in only modest yield improvements, insufficient to justify the expense for smallholder farmers without subsidies.
Too Many Papers, Not Enough Proof
Researchers express another concern: the proliferation of biochar research resembles a bubble.
Scientific papers on biochar surged from fewer than 10 annually in the early 2000s to over 1,000 by the 2020s. Researchers note that biochar now receives more attention than older topics like acid rain, which was a significant environmental issue studied for decades.
This increase largely stems from a small group of highly active authors. A 2023 report in Nature revealed that the number of scientists publishing over 60 papers annually—more than one per week—has nearly quadrupled in under ten years. Biochar exemplifies this, with a few names dominating the field and shaping its perceived maturity.
Institutional warning signs have emerged. According to Clarivate’s Web of Science index, two major journals that published significant biochar research, Chemosphere and Science of the Total Environment, were delisted for failing to meet editorial standards. Investigations uncovered issues like peer-review manipulation, fake reviewer identities, and questionable authorship practices. This indicates the scientific community’s pushback on a field advancing too rapidly without sufficient evidence.
The concern isn’t that biochar researchers are dishonest, but that career incentives favor rapid publishing over careful research. Field experiments are slow and costly, while lab results are quicker. When the rush to publish surpasses verification, fields can overestimate their progress, leading to a crash when reality sets in. Biochar holds value, but its scale must align with environmental and economic realities.
What Would an Effective Biochar Path Look Like?
The Nature Sustainability report doesn’t dismiss biochar. Instead, it advocates for a reset: fewer publications, more verification; reduced speed, more thorough research.
Specifically, the researchers recommend:
- Pre-registered trial designs to prevent selective reporting of results
- Open data and public protocols allowing independent researchers to verify one another’s work
- Dedicated “verification articles” replicating influential findings before new claims accumulate
- Funding allocated for confirmatory studies and even negative results—research that highlights what doesn’t work as well as what does
- Evaluation metrics rewarding verified contributions over sheer publication counts
The acid rain analogy is instructive. In the 1980s, acid rain was a prominent environmental crisis, subject to intense scientific and policy debate. It faded from the headlines not because the issue was imaginary, but due to coordinated policies—cleaner fuels, emission standards, pollution controls—that significantly reduced sulfur dioxide and nitrogen oxide emissions. Ecosystem recovery evidence followed. The field progressed from alarm to action to outcomes, a model worth emulating.
For biochar, the key is transparency about its capabilities and limitations. More real-world projects are operating within these constraints.
Five Biochar Projects To Watch
Despite significant challenges, some biochar projects worldwide are achieving success. They typically utilize local waste materials and generate income from more than just carbon credits.
Exomad Green — Bolivia
Exomad Green is currently the largest biochar producer globally, with two facilities collectively removing about 260,000 tons of COâ‚‚ per year. The feedstock consists of sawmill waste, wood residues that would otherwise be openly burned. This material is transformed into biochar through pyrolysis, essentially burning it. The biochar is then donated to indigenous farming communities to enhance degraded soils. In May 2025, Microsoft signed a 10-year agreement with Exomad Green for 1.24 million tons of COâ‚‚ removal, marking the largest single biochar deal ever. The model succeeds because the feedstock is genuinely waste material with no alternative use, and the soil co-benefits for local communities are genuine and documented.
Pacific Biochar — California, USA
Pacific Biochar has developed a model centered on genuine dual benefits: collecting organic material from forests with high wildfire risk, reducing the fuel load that exacerbates fires, and converting this material into biochar for agricultural use. In 2024, CDR.fyi recognized Pacific Biochar as the global leader in durable carbon removal deliveries, accounting for 21% of the total global certified volume. The focus on California matters—the state’s wildfire crisis creates an almost inexhaustible supply of biomass that genuinely requires removal from the landscape, rendering the feedstock economics particularly robust.
Novocarbo — Germany
Novocarbo represents a different economic logic: the “Carbon Removal Park” model, where biochar production is coupled with renewable energy generation. At its flagship facility in Grevesmühlen, Germany, plant residues are converted into biochar using advanced pyrolysis units, and the waste heat from this process—about 6,600 megawatt-hours annually—is distributed to approximately 1,800 nearby households for heating. Carbon credits are one revenue stream; district heating fees are another. This diversification reduces dependence on volatile voluntary carbon market prices. Novocarbo secured €27 million in new funding in 2025 to expand the model across Europe.
Aperam BioEnergia — Brazil
Aperam BioEnergia, certified by Puro.earth, is among the most established biochar projects in the Global South. Operating in Minas Gerais, Brazil, it converts forestry residues into biochar, with plans to produce 30,000 tons annually by 2026. The project has sold more than 100,000 tons of carbon removal credits since 2021 and supports sustainable forest management practices alongside its production. It’s a model that pairs industrial scale with regional feedstock—the biomass inputs are sourced nearby, minimizing transport emissions.
Carbonity / Airex Energy — Québec, Canada
Airex Energy’s pyrolysis technology underpins Carbonity’s new facility in Port-Cartier, Québec, set to become the largest biochar plant in North America. The project, backed by a consortium including Groupe Rémabec and SUEZ, represents roughly CAD 80 million in investment and aims to produce 10,000 tons of biochar in 2025, scaling to 30,000 by 2026. The feedstock consists of forest residues from the surrounding region. Microsoft has already purchased 36,000 carbon credits through an associated supply deal. While notable for its scale, the project also faces scrutiny due to its large industrial operations in sensitive northern ecosystems.
Local, Small, and Real
These five projects share a vital characteristic. The strongest ones, both economically and environmentally, utilize waste materials, operate near their source to reduce transport emissions, and derive value beyond merely selling carbon credits.
This conclusion is what the Nature Sustainability researchers hint at, even if not explicitly stated. The biochar projects most likely to endure and make a genuine impact are those that would remain viable even if the voluntary carbon market disappeared tomorrow. Their feedstock is free or nearly so, their soil benefits are real and local, and their energy co-products add further value.
The dream of rapidly scaling biochar to significantly reduce the 36 billion tons of CO₂ emitted each year is unlikely to succeed. The numbers don’t add up—not now, and perhaps not ever—unless there are substantial changes in cost, feedstock availability, and the speed at which science is validated.
That doesn’t mean abandoning biochar. Instead, we should be clear about what it represents: a practical, long-lasting, local method of converting waste into something valuable, with tangible benefits for farmers and soil, and a meaningful—if modest—role in carbon removal. Not everything needs to save the world to be valuable.
The lesson from acid rain research and responses is applicable here as well: the goal isn’t to chase new research endlessly. It’s to allow evidence to catch up, support projects that withstand thorough scrutiny, and build something enduring. The future will likely include many smaller, local biochar initiatives, not monolithic, world-saving programs that over-promise, potentially undermining a valid carbon sequestration strategy.
What You Can Do
- Support verified projects. If you or your organization purchases carbon offsets, seek biochar credits certified by Puro.earth or Verra with transparent feedstock sourcing and publicly available lifecycle data.
- Ask about feedstock. Not all biochar is created equal. Biochar made from waste materials that would otherwise be burned or decompose has far stronger climate credentials than biochar produced from purpose-grown crops.
- Look for local applications. Some municipalities and agricultural extension programs are exploring biochar for compost enhancement and soil remediation. Local applications with local feedstocks are the most ecologically sound.
- Be skeptical of big numbers. If a company or project claims to sequester millions of tons of CO₂ per year through biochar alone, request to see the verified delivery data—not just projections.
- Follow the science, not the hype. The International Biochar Initiative maintains a more grounded overview of the field’s actual state of knowledge.
