Methodology

The end ofestimation.

Conventional forest carbon credits are issued against a modelled baseline. PEM GHG-UMO.1 issues against measured net carbon flux over the programme area. TenTrinity Carbon holds exclusive use rights to the protocol.

The proposition

A conventional forest carbon baseline is a counterfactual. It estimates what would have happened to the forest without the project, and that estimate is modelled at design, defended at validation, and revisited when the applicable methodology is revised. Verra and Gold Standard have both tightened their requirements considerably over the past decade, though the quantity being credited remains an estimate.

GHG-UMO.1 quantifies on a different basis. Net carbon flux over the programme area is measured by satellite on a one to two day revisit, and issuance follows that measurement. The protocol has no counterfactual scenario at all.

Most diligence questions on forest carbon now reduce to one: show the record.

The protocol is built to answer it.

The instrument

What the record is made of.

500 mGround resolutionEvery observation resolves to a half-kilometre cell.

1–2 daysRevisit intervalThe same ground is re-observed within one to two days.

2.7M+Observations each yearRecorded continuously across the programme area.

25 yearsContinuous archiveA quality-screened public record, without gaps.

The instrument

Measured from orbit.

How it works

Observation to issuance.

The protocol fixes its inputs, its model and its output record at the outset. Because the model version and parameter set are locked for the life of the programme, a determination made in year thirty is directly comparable with one made in year one.

01
A quality-screened public archive
The protocol reads a public satellite archive covering every hectare of the programme area on a one to two day revisit. Because the archive is public and quality-screened before use, the operator cannot select which observations enter the quantification.
02
A version-locked model
A peer-reviewed biosphere model, locked in version and parameters for the life of the programme, converts those observations into measured net carbon flux. Because the version is fixed at the outset, later determinations are not affected by subsequent revisions to the model.
03
Measured net flux
Flux is determined annually and reported quarterly across the programme area. Every year of the crediting period is covered by observation, so performance does not have to be reconstructed at audit.
04
Serialised issuance
Issuance follows the measurement. Each unit is serialised to the hectares it was measured over, so a buyer can trace a credit back to the specific area and period that produced it.
05
An open record
The input and output record is lodged in a permanent public archive, and a counterparty working from the same data can reproduce the reported figures. The protocol also specifies how successor satellites are brought in, so the record continues across sensor generations without a change of method.

Monitoring cadence

The same twenty-five years, seen two ways.

How often a programme is observed determines how quickly a problem surfaces. Under periodic verification a project is examined roughly once every five years, and no measurement is taken between those audits. Under GHG-UMO.1 the programme area is observed every one to two days for the whole crediting period. The figure below draws the same twenty-five years on both bases.

Estimation architecture

Examined at verification, typically once in five years.

verification events

Direct measurement

The same ground re-observed every one to two days.

≈6,000

observation passes

Both rows draw the same twenty-five-year crediting period on the same scale. The observation-pass figure is arithmetic rather than a claim: a one to two day revisit over twenty-five years gives between roughly 4,500 and 9,000 passes over the programme area, and the figure shown is the midpoint. Each pass records millions of individual cell observations. Marks on the lower row are indicative of cadence and are not drawn one to one.

Comparative analysis

The same six questions, put to three architectures.

Set the same questions before the three architectures and the differences are structural rather than a matter of degree. Verra VCS and Gold Standard answer from a constructed scenario, refined by two decades of governance. GHG-UMO.1 answers from the observed record.

Comparison of baseline, scope, monitoring, fieldwork, leakage and data access across Verra VCS, Gold Standard and PEM GHG-UMO.1.
Criterion	Verra VCS	Gold Standard	PEM GHG-UMO.1
Baseline	Verra VCSCounterfactual, built from jurisdictional risk maps and matched-control benchmarks.	Gold StandardCounterfactual, built as a project-specific baseline scenario.	PEM GHG-UMO.1No modelled scenario. The observed flux record is itself the reference.
Eligible scope	Verra VCSAvoided deforestation, afforestation and improved forest management, under separate methodologies.	Gold StandardAfforestation and reforestation, soil and agriculture. Avoided deforestation is excluded by policy.	PEM GHG-UMO.1Any terrestrial landscape, standing forest included, under one protocol.
Monitoring	Verra VCSPeriodic verification, typically on five-year cycles.	Gold StandardPeriodic verification on multi-year cycles.	PEM GHG-UMO.1Continuous. A one to two day revisit, with annual determination and quarterly reporting.
Fieldwork	Verra VCSPlot networks with remote-sensing support.	Gold StandardPlot-based inventory and allometric models.	PEM GHG-UMO.1Instrument-based. No field campaigns are required to quantify.
Leakage	Verra VCSModelled deductions, using leakage belts and factors.	Gold StandardAssessed through modelled deductions.	PEM GHG-UMO.1Observed directly across a defined monitoring zone.
Data access	Verra VCSProject documents are published; raw data is rarely public.	Gold StandardProject documents are published; raw data is rarely public.	PEM GHG-UMO.1The complete record is lodged in a permanent public archive.

Characterisations of Verra VCS and Gold Standard reflect their current forest methodologies and public programme documents as consulted in August 2026. Both standards revise their requirements from time to time; counterparties should consult the source documents directly.

The case

Grounds a committee can minute.

The case

Five grounds an allocation committee can minute.

Each of the following can be checked against the archived record before a counterparty transacts.

Baseline

There is no baseline scenario for a project to set in its own favour.

Baseline discretion was central to the repricing of forest carbon in recent years. Under a counterfactual method the project sets the number that determines its own issuance, and buyers have limited means of testing it. GHG-UMO.1 has no such number. Issuance follows an observation of the programme area that was recorded independently of the project.

Performance

A disturbance appears in the measured record within days of occurring.

Under periodic verification, a loss between audits is only detected at the next one, which may be several years later. Continuous observation shortens that gap to days. For a buyer this changes what the credit evidences: the forest is not simply reported as intact at the last examination, it is observed across the whole period.

III

Reproduction

A counterparty can re-run the reported figures and get the same answer.

The inputs are drawn from a public archive and the model is locked in version and parameters, so the quantification can be repeated independently. A buyer who wants to test an issuance does not have to rely on the operator's account of it, and can instead reproduce the calculation from the archived record.

Durability

A completed measurement is not revised when the methodology changes.

Estimation methodologies are periodically revised, deprecated or re-baselined, and holdings issued under them have been repriced when that happens. A measurement taken under a locked model version is unaffected by later changes to the model, which gives a holder a more stable basis for valuing an inventory over a long crediting period.

Allocation

Fifteen per cent of net sales proceeds is allocated to communities, and audited.

The commitment is documented in an allocation schedule that records, for each vintage, the amount allocated, its status through to implementation, and the supporting evidence. A verifier can therefore follow the money from the sale of a credit to the intervention it funded.

Provenance and assurance

Where the methodology comes from.

Developer: PEM GHG-UMO.1 is developed and owned by Planetary Emissions Management Inc. of Cambridge, Massachusetts. TenTrinity Carbon does not own the methodology and does not present it as proprietary to the company.
Exclusivity: TenTrinity Carbon holds exclusive use rights to the protocol for the programmes it originates and places. Counterparties transacting on GHG-UMO.1 supply through other channels should verify the basis on which it is offered.
Verification: RINA S.p.A. has confirmed that verification of the methodology is complete. The verification report is scheduled for issue in September 2026 and will be released to qualifying counterparties through the data room.
Reference implementation: The Shabunda Forest Carbon Legacy Project in the Democratic Republic of Congo is the reference implementation. It is published on this site as two tranches: the first has issued against measurement for every vintage from 2001, and the second has not been measured yet.
Scope of this page: This page describes what the protocol delivers. It does not publish the model, its parameters or the quantification method, which remain the developer's intellectual property.

The company’s wider position on measurement over estimation is set out in the Measure commitment.

Show the record.

Every unit issued under GHG-UMO.1 can be traced to the measurement it came from and the archived data behind it.

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