Forest-based biomass carbon removal and storage (BiCRS) has drawn legitimate concerns. Poorly designed projects have overstated their climate impact, ignored the full lifecycle of emissions, and raised questions about deforestation.
But the way forward isn't to write off BiCRS entirely, especially since there is enough waste biomass to remove 2.5–5 Gt of CO₂ per year (2021 BiCRS Roadmap). Getting it right matters because it could be one of the most scalable approaches to carbon removal in the next decade.
That means doing two things: (1) applying rigorous standards to every project so its climate impact holds up to scrutiny, and (2) taking advantage of the broad range of feedstocks the pathway can draw on.
Concerns about forest-based biomass projects
Researchers and NGOs have raised a number of legitimate concerns about forest-based biomass projects. These include:
Narrow accounting: Some BiCRS projects use forest biomass without accounting for CO₂ that's emitted as part of harvesting operations, wood processing, transportation, and the portion of carbon not captured when wood is burned (Searchinger et al. 2026). If those emissions are not properly accounted for, then the climate impact of the BiCRS project is overstated. That happens when biomass is treated as carbon neutral by default, which is not necessarily the case, especially for wood harvesting.
Protocols failing to consider the counterfactual: One question every project should ask is "What would have happened to the biomass if the CO₂ capture and storage project didn't exist?" (Herbstritt et al. 2026). In some cases, the counterfactual isn't rapid biomass decay, but rather continued storage either in standing timber or slow-decaying reservoirs (such as branches and logs left on the forest floor). The biomass can also be reused for things like fertilizer and animal feed. This matters because carbon removal only happens when the biomass would have otherwise decayed and released carbon back into the atmosphere.
Increasing demand for forest harvesting: When wood that would otherwise supply industries such as pulp and paper is diverted to carbon removal, additional forests may be harvested to fill the gap. If that additional harvesting reaches old-growth forests, which store 70% more carbon than previously logged forests, the resulting emissions can far outweigh the carbon removal benefits of the original project (Pascual et al. 2026). Excessive forest harvesting also reduces biodiversity, disrupts water cycles, and increases soil erosion.
These concerns point to flaws in how some projects are designed, rather than undercutting the viability of all BiCRS approaches.
What rigorous BiCRS looks like in practice
Frontier members have committed over $360M in offtake agreements with eight BiCRS companies, and turned down projects that didn't meet Frontier's bar. In each case, our biomass sourcing principles guided our diligence, directly addressing the concerns above. These principles include:
Accounting for a project's lifecycle emissions. For example, installing a carbon capture system reduces heat and/or electricity exported to the local grid. This can result in an increase in emissions elsewhere in that system, which we include when we count emissions against gross CO₂ captured and stored.
Avoiding sourcing from old-growth forests. We apply this to every project, even if the biomass is waste from another industry. For example, we have declined to purchase from projects that use residues from timber production if the timber is sourced from old-growth forests.
Avoiding areas where sourcing biomass reduces the stock of carbon over time. We look at regional data to determine whether there is a net increase or decrease of carbon, avoiding purchases from projects operating in areas where harvest rates exceed regrowth. This regional check is separate from, and doesn't replace, verifying that the biomass is low carbon and would have otherwise rapidly decomposed. Both questions need a satisfactory answer.
Prioritizing biomass that would otherwise decompose quickly. Carbon removal happens when biomass feedstocks would have otherwise decayed and released their carbon back into the atmosphere. We prioritize projects using agricultural residues such as small branches, leaves, and sawmill residues, where that decay is fastest, and in regions where those materials have no established alternative use.
Using wastes and residues rather than dedicated energy crops. Producing crops or managing timber plantations can involve substantial emissions, both through direct inputs and indirect land-use changes (e.g., displacing existing natural forests or grasslands). Using waste and residue biomass from existing forestry or agricultural operations avoids new emissions from biomass production.
Beyond forest biomass
Much of the debate around BiCRS has focused on forest biomass, but that's only one of several types of feedstocks that projects can use. These include:
Agricultural residues such as corn stover and wheat straw. These residues could account for nearly double the annual carbon removal of forest waste: approximately 1–6 Gt of carbon removal per year, considering total global biomass availability and assuming a carbon removal efficiency of 90% (Slade et al. 2024). A sizable portion of this material should be left on fields to replenish nutrients and build soil carbon, but there is excess that decays quickly to CO₂. Charm Industrial (pyrolysis to produce bio-oil) and Reverion (fuel cells operating at anaerobic digesters) convert those excess agricultural residues into permanent carbon dioxide removal (CDR). Both also produce coproducts such as biochar and digestate that return nutrients to croplands and reduce emissions associated with fertilizer production.
Organic waste such as sewage sludge, manure, and anaerobic digestate. That waste could account for approximately 0.5 Gt per year (Frontier analysis of IEA data). Vaulted Deep directly injects biomass waste into wells deep underground, a form of carbon removal that has the added benefit of avoiding methane emissions. Manure can be codigested in Reverion's system and similarly returned to fields as a nutrient.
Municipal solid waste, such as household trash, that is incinerated at waste-to-energy (WtE) facilities could yield 0.6 Gt per year of carbon removal (Frontier analysis of World Bank data). The carbon in this waste is typically 50% biogenic CO₂ from organic materials like food and paper, and 50% fossil CO₂ from plastics and synthetic materials. Companies such as Hafslund Celsio are installing carbon capture units at WtE plants, so that the biogenic fraction of the plant's emissions can contribute to carbon removal. This approach has the added benefits of capturing fossil CO₂ and avoiding methane emissions from landfills.
Industrial biowaste such as effluent sludges from vegetable oil production; oat hulls; fats, oils, and grease (FOG); or dairy processing waste can be converted to bio-oil via hydrothermal liquefaction, which permanently removes CO₂ from the atmosphere, while helping industrial sites manage their waste. Companies like NULIFE GreenTech can convert industrial waste as well as a wide range of feedstocks to bio-oil, including manure, sewage sludge, and crop residues.
Post-construction woody waste such as fiberboard and other waste wood that cannot be recycled or reused could remove more than 150 million tons of CO₂ per year (Frontier analysis of Logistics Cluster data).
Done right, BiCRS could drive a meaningful share of the gigaton-scale portfolio the world needs, alongside deep emissions reductions. The feedstocks exist and so do the standards to source them responsibly. What's needed now is buyers, and ultimately governments, who demand every project meets those standards and apply them rigorously.