Picture turning yard waste, wood scraps, and farm leftovers into something that stores carbon underground for centuries and improves soil health. That’s the idea behind biochar. While this is true, it doesn’t tell the full story.
For over twenty years, researchers, entrepreneurs, and climate advocates have promoted biochar as a top way to remove carbon dioxide from the air. Early estimates said it could take out 3.4 to 6.3 billion tons of CO₂ each year, which is huge. This excitement led to many scientific papers, startup investments, and carbon credit deals.
But a new analysis in Nature Sustainability from January 2026 says we should slow down. Biochar is real, but the excitement has gotten ahead of the facts. The researchers warn that too much hype could lead to a “boom-and-bust cycle” that ends up hurting the technology.
What Is Biochar?
Biochar is charcoal, but not the kind you use at a backyard cookout. It’s made by heating organic materials such as wood chips, crop waste, or agricultural byproducts in a low-oxygen environment through a process called pyrolysis. The result is a dark, porous, carbon-rich material that resists breaking down in soil for centuries or even millennia.
The inspiration came from an unlikely source: ancient Amazonian soils. Researchers discovered that the region’s famously fertile “terra preta” (Portuguese for “dark earth”) owed its richness to charcoal that Indigenous peoples had mixed into the soil thousands of years ago. That charcoal had survived intact, still improving soil structure and fertility long after the civilization that made it passed into history.
When scientists studied terra preta, they realized that locking carbon in a solid form and burying it in soil removes it from the air for a long time. Biochar looked like a win-win: it could store carbon and help farms. This led to more funding, research, and new companies.
The Numbers That Raised Alarms
The issue isn’t that biochar doesn’t work, but it hasn’t lived up to the early high hopes. The Nature Sustainability analysis by Italian soil scientists Luciano Gristina and Riccardo Scalenghe explains the numbers in detail.
Let’s look at production. All certified biochar facilities in the world make about 350,000 tons each year. That might sound like a lot, but spread over the world’s 1.5 billion hectares of farmland, it’s tiny. The researchers found that this would raise the soil surface by less than one-tenth the width of a human hair per year. This shows how far current production is from what’s needed for climate goals.
Next is the question of carbon storage. Biochar’s actual impact is about a thousand times smaller than early estimates. Even after subtracting the emissions from making it, the net climate benefit is only a few hundred thousand tons of CO₂ at most. For comparison, global emissions are about 36 billion tons each year.
Economics make things even harder. Studies show that feedstock—the raw material for biochar—can make up as much as 75% of the total cost. So, biochar projects only make financial sense if they have free or very cheap biomass, or steady income from carbon credits. Without these, most projects aren’t profitable.
In Southeast Asia, trials showed that adding biochar to farmland produced only modest yield improvements, not nearly enough to justify the cost for smallholder farmers without a subsidy.
Too Many Papers, Not Enough Proof
The researchers have another worry: there is so much research on biochar now that it looks like a bubble.
Scientific papers on biochar have jumped from fewer than 10 a year in the early 2000s to over 1,000 a year by the 2020s. The researchers point out that biochar now gets much more attention than older topics like acid rain, which was a major environmental issue studied for decades.
Much of this increase in papers comes from a small group of very active authors. A 2023 report in Nature found that the number of scientists publishing over 60 papers a year—more than one per week—has almost quadrupled in less than ten years. Biochar is a clear example, with a few names dominating the field and shaping how mature it seems.
There are now warning signs from institutions. According to Clarivate’s Web of Science index, two major journals that published a lot of biochar research, Chemosphere and Science of the Total Environment, were removed from the index for not meeting editorial standards. Investigations found problems like peer-review manipulation, fake reviewer identities, and unusual authorship practices. This shows that the scientific community is starting to push back on a field that may be moving too quickly for the evidence.
The worry isn’t that biochar researchers are being dishonest. It’s that career incentives reward publishing quickly rather than publishing carefully. Field experiments are slow and expensive. Lab results are faster. When the pressure to publish outpaces the ability to verify, fields can develop an inflated sense of their own progress, and then crash when reality catches up. Biochar has value, but it must be scaled to the right size to make environmental and economic sense.
What Would an Effective Biochar Path Look Like?
The Nature Sustainability report doesn’t say biochar is a lost cause. Instead, it suggests the field needs a reset: fewer papers, more checking; less speed, more solid research.
Specifically, the researchers call for:
- Pre-registered trial designs so that results can’t be cherry-picked after the fact
- Open data and public protocols that allow independent researchers to check each other’s work
- Dedicated “verification articles” that reproduce influential findings before new claims pile on top of them
- Funding earmarked for confirmatory studies and even negative results — research that shows what doesn’t work, not just what does
- Evaluation metrics that reward verified contributions over sheer publication counts
The acid rain parallel is instructive. In the 1980s, acid rain was a front-page environmental crisis, the subject of intense scientific and policy debate. It receded from headlines not because the problem was imaginary, but because coordinated policy — cleaner fuels, emissions standards, pollution controls — actually reduced sulfur dioxide and nitrogen oxide emissions. Evidence of ecosystem recovery followed. The field moved from alarm to action to outcome, a model worth following.
For biochar, the right approach is to be honest about what it can and can’t do. More real-world projects are now working within these limits.
Five Biochar Projects To Watch
Even with big challenges, some biochar projects around the world are finding success. They usually use local waste materials and earn money from more than just carbon credits.
Exomad Green — Bolivia
Exomad Green is currently the world’s largest biochar producer, operating two facilities that together remove about 260,000 tons of CO₂ per year. The feedstock is sawmill waste, wood residues that would otherwise be open-burned. The material is converted into biochar through pyrolysis, in other words, it is burned. That biochar is then donated to indigenous farming communities to improve degraded soils. In May 2025, Microsoft signed a 10-year agreement with Exomad Green for 1.24 million tons of CO₂ removal; the largest single biochar deal ever made. The model works because the feedstock is genuinely waste material with no better use, and the soil co-benefits for local communities are real and documented.
Pacific Biochar — California, USA
Pacific Biochar has built its model around a genuine dual benefit: it collects organic material from forests with high wildfire risk, reducing the fuel load that makes fires catastrophic, and converts that 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 total global certified volume. The California focus matters: the state’s wildfire crisis creates a near-endless supply of biomass that genuinely needs to be removed from the landscape, making the feedstock economics unusually solid.
Novocarbo — Germany
Novocarbo represents a different economic logic: the “Carbon Removal Park” model, where biochar production is bundled 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 that process — about 6,600 megawatt-hours per year — is piped to roughly 1,800 nearby households for heating. Carbon credits are one revenue stream; district heating fees are another. That diversification makes the project less dependent on voluntary carbon market prices, which can be volatile. 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 one of 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 produced nearby, keeping transport emissions low.
Carbonity / Airex Energy — Québec, Canada
Airex Energy’s pyrolysis technology is the backbone of Carbonity’s new facility in Port-Cartier, Québec — slated 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 is forest residues from the surrounding region. Microsoft has already purchased 36,000 carbon credits from an associated supply deal. The project is notable for its scale, but also carries the scrutiny that comes with large industrial operations in sensitive northern ecosystems.
Local, Small, and Real
These five projects have something important in common. The strongest ones, both economically and environmentally, use waste materials, work close to where those materials come from to cut transport emissions, and find value beyond just selling carbon credits.
That’s the conclusion the Nature Sustainability researchers point toward, even if they don’t say it quite so directly. The biochar projects most likely to survive and do genuine good are the ones that would still make sense even if the voluntary carbon market collapsed tomorrow, because their feedstock is free or nearly free, their soil benefits are real and local, and their energy co-products create additional value.
What likely won’t work is the dream of scaling biochar fast and wide enough to make a big dent in the 36 billion tons of CO₂ released each year. The numbers just don’t add up—not now, and maybe not ever—unless there are big changes in cost, feedstock supply, and how quickly the science can be checked.
That doesn’t mean we should give up on biochar. Instead, we should be clear about what it is: a useful, long-lasting, local way to turn waste into something valuable, with real benefits for farmers and soil, and a real—if small—role in removing carbon. Not everything has to save the world to be worthwhile.
The lesson from the acid rain research and responses fits here too: the goal isn’t to keep chasing new research. It’s to let the evidence catch up, support projects that stand up to close review, and build something lasting. The way forward will include many smaller, local biochar initiatives, not monolithic, world-saving programs that over-promise, threatening a valid carbon sequestration strategy.
What You Can Do
- Support verified projects. If you or your organization purchases carbon offsets, look for 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 much 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, ask 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.
The post Biochar Was a Billion-Ton Dream, the Reality Is More Complicated appeared first on Earth911.
- Source: https://earth911.com/eco-tech/biochar-was-a-billion-ton-dream-the-reality-is-more-complicated/
