Why four carbon routes, not one
The voluntary carbon market has had a hard two years. Investigative reporting in 2023 raised serious questions about the integrity of legacy REDD+ baselines; buyer pull-back followed; transaction volumes fell. The market's response has been to filter hard rather than to retreat: ICVCM's Core Carbon Principles, the methodology updates at Verra (VM0048 for REDD+, JNR v4.1 for jurisdictional, VM0045 for IFM, VM0047 for ARR), and the rise of ART TREES for jurisdictional approaches have all converged on one direction. Tighter rules. Better evidence. Fewer tonnes, but each one defensible.
EDMA's carbon framework is built for that filtered market. The four routes cover the activity classes where credible nature-based and engineered removals or avoided-loss claims exist today: tree planting (R5), forest protection and improved management (R6), coastal ecosystems (R7), and soils plus biochar (R8). Each route operates only on the methodology family that has cleared the relevant integrity bar (CCP labels where applicable, EBC and IBI for biochar).
What is shared across the four is the evidence chain. GRO is the non-transferable evidence token that binds field measurements, lab assays, remote sensing, and verifier sign-off to one tamper-evident on-chain record. Every route runs through the same additionality gate, the same locked-accounting-plan discipline, the same mandatory retirement of overlapping instruments, the same ex-post verifier panel, and the same One-Claim Ledger that prevents the same unit of benefit being claimed twice.
The four routes at a glance
Each card below is one carbon route. The Asset column shows what generates the evidence; the Methodology column points to the recognized methodology family the route operates on; the Buffer column shows the permanence-buffer sizing (the share of issued tonnes held back to insure against future reversal); the Stacking column shows what the One-Claim Ledger allows to coexist.
R5 and R6 are forestry. R7 is coastal. R8 covers soils and biochar in two sub-paths. The buffer percentages are not arbitrary: they reflect the documented permanence risk profiles for each ecosystem and methodology family.
R5 - Reforestation (ARR)
R5 (ARR) covers afforestation, reforestation, and assisted natural regeneration. Trees and other woody vegetation remove CO2 from the atmosphere and store it in living biomass and in soil. The methodology basis is Verra VM0047 (CCP-eligible under ICVCM) or equivalent ARR frameworks. The MRV stack combines field plot measurements with allometric biomass calculations, remote sensing (optical and radar) for canopy and area, and laboratory analyses where required.
R5 is designed for the high-integrity slice of the ARR market: native-species projects with credible tenure and FPIC, in regions where the carbon revenue is the difference between a viable and a non-viable project. Pricing reality across 2024-25 places high-integrity ARR in the $20-60 per tonne band (illustrative, not guarantees); the slice that pays cleanly is buyers who screen for CCP labels and audit-ready evidence. Read the R5 page for the full seven-stage flow and the worked accounting examples.
R6 - REDD+ / IFM (Avoided Loss)
R6 (REDD+ / IFM) covers avoided emissions from stopping at-risk deforestation (REDD+) and from improved forest management (IFM, including longer rotations, reduced-impact logging, and conservation set-asides). The methodology basis is the CCP-eligible family: Verra VM0048 for project-scale REDD+, Verra JNR v4.1 for jurisdictional REDD+, ART TREES v2.0 for jurisdictional, and Verra VM0045 for IFM.
R6 is built for the filtered REDD+ and IFM market that emerged after 2024. The 2023-era baseline criticisms are addressed by operating only on the new-generation methodologies that include allocated deforestation risk maps and explicit leakage budgets. The locked accounting plan at S02 records the methodology version on-chain; the deductions and buffer are published before issuance. Pricing reality across 2024-25: REDD+ in the $7-20 per tonne band with strong stories clearing $20-40; IFM clustered around $15-16 per tonne (illustrative, not guarantees). Read the R6 page for the methodology lineage and the gate criteria.
R7 - Blue Carbon
R7 (Blue Carbon) covers coastal ecosystems: mangroves, saltmarsh, and seagrass. These ecosystems store carbon in living biomass and (uniquely among nature-based routes) in marine sediment, where it can remain stable over centuries to millennia. The MRV stack is coastal-specific: sediment cores measure bulk density and percent organic carbon by depth; biomass plot surveys capture above-ground stocks; elevation monitoring (rSET-MH where applicable) tracks subsidence and accretion; remote sensing measures area.
R7 is designed for the supply-constrained blue-carbon market. Industry estimates place annual issuance under 10 Mt globally, with the integrity premium reflecting both the MRV chain and the elevated permanence buffer (typically 15-25% to account for storm, erosion, and sea-level rise risk). Activity-shifting leakage, such as aquaculture relocation, is included in the locked accounting plan. Read the R7 page for the coastal MRV details and the buffer sizing rationale.
R8 - Soils & Biochar
R8 (Soils & Biochar) covers two distinct sub-paths sharing one protocol skeleton. The soils path delivers practice-based SOC gains through farming practice change (reduced or no-till, cover crops, residue retention, improved grazing); typical accrual ranges from 0.2 to 0.7 tCO2 per hectare per year in credible programmes, pricing in the $10-30 per tonne band (illustrative, not guarantees). The biochar path delivers durable removals through pyrolysis of biomass into stable carbon forms applied to soils or embedded in long-lived materials; pricing typically $80-200+ per tonne reflecting measurable durability.
R8 separates the two sub-paths cleanly at every stage. Soils receives a higher permanence buffer to insure against practice-reversal risk (tillage re-release). Biochar receives a lower buffer reflecting durability, but requires EBC or IBI-aligned QA on assays, contaminants, and chain-of-custody. Energy co-products from biochar pyrolysis are accounted for on energy Routes 1 or 2 and never counted toward the carbon claim, enforcing the one-claim rule at the contract level. Read the R8 page for both sub-paths and the QA requirements.
Stacking: what the One-Claim Ledger allows
The One-Claim Ledger enforces one rule across all four carbon routes (and across the energy routes): one unit of benefit, one claim. A hectare cannot be claimed for ARR removal and REDD+ avoided-loss simultaneously. A tonne of biochar cannot be claimed for both carbon and for the energy co-product. A coastal area cannot be claimed for both blue-carbon and biodiversity offsets unless one is retired first.
Within that rule, several stacking patterns work. Different areas, different routes is always allowed: R5 inland and R7 on the coast on separate plots of land within the same project. Different units of benefit on the same area can be allowed if the methodology supports it: ARR removal on R5 (the trees) plus biodiversity offsets in a different registry (the habitat) is allowed where neither double-counts the other. Carbon plus energy stacking always requires the overlapping energy attributes to be retired first (the same rule as R4 in the energy routes).
What cannot stack is the same unit of benefit issued in two registries. The protocol reverts at the contract level if anyone tries. The retirement records carry the one-claim discipline as their first-class property.
What's shared across all four
Every carbon route runs the same protocol stack:
GRO evidence token. Non-transferable, mints as monitoring data lands (per plot, transect, sample event, or reactor batch), consumed at issuance and rendered permanently non-transferable. GRO is the spine that ties field crews, labs, RS providers, and verifiers to one tamper-evident chain.
Additionality gate (S01). Binary verdict with published criteria, fast reroute to other lanes on fail. The protocol cannot mint without a pass.
Locked accounting plan (S02). Methodology version, baseline framework, leakage budget, uncertainty deductions, and permanence buffer all recorded on-chain at the start of each vintage batch. Restatement SOP applies if upstream sources change; settled batches are never repriced.
EAC retirement (S04). Any overlapping instruments must be retired or immobilized in their source registry before the protocol will proceed to mint carbon tonnes. The Issue and Retire IDs are anchored on Ethereum L1.
Ex-post verifier panel (S05). Independent accredited verifiers review the vintage batch dossier off-chain and sign on-chain with their attestor identity. Cadence is published in advance.
One-Claim Ledger. The cross-protocol primitive that prevents the same unit of benefit from being claimed twice. Keys differ by route (per-plot at S04 for ARR; per-area for REDD+; per-transect for blue carbon; per-sample or per-batch for soils and biochar) but the rule is uniform across all carbon routes.
Where it stands
All four carbon routes share the protocol-level architecture already shipped for the energy routes (PoV Gate, One-Claim Ledger, Attestor Registry, Ethereum L1 anchoring). The carbon-specific build-out is in four areas:
GRO evidence-token contract. Parallel to the ETT contract used for energy routes, but tuned for the carbon evidence schemas (plot measurements, sediment cores, reactor logs).
Verifier panel onboarding. The independent verification firms accredited by the major voluntary registries (the recognised VCS, Gold Standard, and ART verifier rosters) are admitted to the Attestor Registry as VERIFIER-class entities. The panel is built jurisdiction by jurisdiction.
Methodology version tracking. The locked accounting plan at S02 records the methodology source and version. As methodologies update (Verra has been actively iterating VM0047, VM0048, and VM0045), the protocol's re-issuance SOP keeps the lineage clear.
Registry bridges. Bridge attestation contracts for the major voluntary registries (Verra VCS, Gold Standard, ART, ACR) so that EDMA-issued tonnes can be exported to those registries where the buyer requires registration there, or so that retirements in those registries can be anchored on-chain for the one-claim discipline at S04.
Carbon-route readiness depends on three signals from the broader market: continued ICVCM CCP labelling of additional methodologies; the voluntary registries' completion of their methodology overhauls (VM0048 transition for REDD+ is the most active workstream); and corporate-buyer adoption of the new-generation methodology standards as their procurement baseline. For the protocol-level architecture the carbon routes depend on, see Proof-of-Verification, One-Claim Ledger, and Attestor Registry.
