Mycorrhizal Fungi Just Generated Their First US Verra-Verified Carbon Credits
- Julie Kriegshaber
- 5 hours ago
- 4 min read
Groundwork BioAg has issued verified carbon units under its Rootella Carbon programme, the first credits generated under Verra's VM0042 standard in the United States and the first "measure and remeasure" project to issue globally.
The credits are underpinned by mycorrhizal fungi, microscopic organisms that colonise plant roots and drive carbon into stable mineral-bound soil pools known as Mineral-Associated Organic Matter, which the company says can persist for centuries.
The issuance signals a maturing voluntary carbon market, but unresolved disagreements over how to measure soil carbon reliably mean the asset class still faces a credibility discount with institutional buyers.
A Fungal Pathway Into the Soil
Mycorrhizal fungi are among the oldest partnerships in biology, having colonised plant roots for roughly 450 million years. In exchange for sugars from the plant, the fungi extend the root system many times over and ferry nutrients back in return. Industrial agriculture, with its heavy tillage and synthetic fertilisers, disrupted much of this symbiosis. Groundwork BioAg, based in Mazor, Israel, sells Rootella, a commercial mycorrhizal inoculant applied across 5.5 million acres globally in 2025, with the aim of restoring that relationship at scale.
The company's Rootella Carbon programme turns a side-effect of that restoration into a tradeable commodity. As fungi colonise roots, they exude compounds that bind carbon chemically to soil minerals, forming Mineral-Associated Organic Matter, or MAOM. Groundwork BioAg reports that this mechanism sequesters between 1.5 and 3.5 tonnes of COâ‚‚ equivalent per acre each year, a rate it claims is approximately five times higher than published benchmarks for common regenerative practices such as cover cropping or no-till farming.
What the Issuance Actually Represents
On 24 June 2026, the company announced it had issued 19,568 net Verified Carbon Units under Verra's Verified Carbon Standard, independently verified by SCS Global Services. The credits were generated under Verra's VM0042 agricultural land management methodology, and this marks the first issuance under that standard in the United States, as well as the first "measure and remeasure" project to issue anywhere globally. Multiple purchase agreements are already in place.
The programme's approach to measurement is deliberately conservative. Rather than relying on satellite imagery or algorithmic models, Groundwork BioAg physically sampled soil, sent it to a laboratory for dry combustion analysis, and compared treated plots against untreated controls. Chief Growth Officer Dan Grotsky has argued that this physical baseline is what risk-averse institutional buyers need, given a voluntary carbon market already scarred by the credibility failures of model-derived credits.
Grower incentives are built into the structure. Enrolled farmers receive up to 70% of net proceeds from credit sales. Enrolment has grown from roughly 9,000 acres in 2023 to more than 700,000 acres across the US Midwest and Canadian Prairies, with the company identifying 450 million acres of reduced-tillage farmland across the Americas as the longer-term addressable market.
Implications for the Climate Market, and What Remains Unresolved
The issuance matters for the voluntary carbon market because it converts a pipeline promise into delivered, verified inventory, something institutional allocators have been waiting for. It also signals that mycorrhizal-mediated carbon removal is emerging as a theme within the voluntary carbon market. Funga, which works with mycorrhizal fungi for forest systems, is developing a new Verra methodology (M0274) with Conservation International, CTrees and The Nature Conservancy built around co-located control plots to measure carbon additionality in tree growth - a different mechanism and ecosystem entirely. The methodology is currently in public comment and expected to be approved later in 2026.
Groundwork's CEO Alon Werber has stated that Rootella Carbon aims to deliver roughly one million tonnes of COâ‚‚e within two years, against a global CDR market that delivered approximately two million tonnes in total last year. That ambition, if realised under third-party verification, would represent a meaningful addition to the supply of high-integrity removals.
Yet the path to institutional scale depends on questions that remain genuinely open. The peer-reviewed science on mycorrhizal carbon permanence is still active, not settled. Research has shown that AMF's effect on soil carbon is genuinely bidirectional: the fungi can drive carbon into stable mineral-bound pools under some conditions, and accelerate its decomposition under others. A landmark study by Lei Cheng and colleagues, published in Science in 2012, demonstrated net soil carbon losses under elevated COâ‚‚,directly challenging the assumption that AMF uniformly protect organic carbon from decomposition. More recent meta-analyses have found a net positive effect on average, but context-dependent enough that soil texture, tillage regime, and COâ‚‚ conditions all shift the outcome. This is precisely why Groundwork BioAg's insistence on physical soil sampling rather than modelled estimates matters: positive results have to be physically measured to be foolproof. The durability of MAOM itself, while widely cited as stable on century timescales, involves biological processes that are harder to guarantee than geological or mineralisation-based storage.
The measurement debate adds another layer. Competing methodologies, physical sampling versus remote-sensing models, sit side by side within Verra's registry without a single agreed standard determining whose tonne counts as a tonne. Until that question is resolved, soil carbon credits, however carefully verified, will continue to trade at a discount that reflects the disagreement rather than the dirt.