Applicant Guidance — Errata and Clarifications No. 1 (F01, F02, F05)
MCC F01 Blue Carbon Guidance v1.0 · F02 Ecosystem Restoration Guidance v1.0 · F05 MPA Management Guidance v1.0 → v1.1
What is being consulted on
Corrects the calculation errors found in the worked examples of the three family guidances (carbon mass written as CO₂e, loss rates applied past the point of stock exhaustion, credit-type and buffer rules restated wrongly), recomputes every example, and asks the Standards Committee to determine which reef carbon pools may count toward the CO₂e component of MCC-HYB units.
- Decision by
- Programme administration under FD-2026-08-24 item 3, with Board oversight (MCC-001 cl. 0083); Part E is referred to the Standards Committee
- After closing
- Every material comment receives a written response; the closing protocol is published here; the decision cites the proposal by its hash; on adoption the text is published at /transparency/documents with a version bump and this consultation is linked from it.
- Proposal SHA-256
cd5618a98354b6edbc45786e75287e6ae42a26772850cbfcf8d9e60ab6f14add- Source file
- MCC_Guidance_Errata_1_F01_F02_F05_v1.1_DRAFT.md
Proposal text hash cd5618a9…b6f14add
MCC Applicant Guidance — Errata and Clarifications No. 1 (F01, F02, F05)
Instrument: Errata to MCC_F01_Blue_Carbon_Guidance_v1.0, MCC_F02_Ecosystem_Restoration_Guidance_v1.0 and MCC_F05_MPA_Management_Guidance_v1.0 Tier: 5 (operational guidance) — amendment by the operational team with Board oversight and 14 days' notice (MCC-001 cl. 0083); the Standards Committee determination requested in Part E is Tier 4 Status: DRAFT for adoption under FD-2026-08-24 item 3 (execution by the administration) — NOT ADOPTED, NOT PUBLISHED Prepared: 25 August 2026 · Basis: Rulebook audit 24 August 2026 (register K5, K6, K13); MCC-100 v2.2 cl. 0167, 0183.1, 0186–0188; Buffer Pool Management Policy v1.0; ESS Policy v1.0 cl. 0011; Definitions Register v1.0
A. Why an errata instrument
The three family guidances were withheld from publication on 25 August 2026 (PR #131) because the rulebook audit found calculation errors in their normative worked examples. A guidance whose example overstates issuable credits by a factor of six teaches applicants to submit overstated PDDs and teaches VVBs the wrong benchmark. Under D16 (change discipline) the corrections are made by instrument, with a version bump to v1.1 and this change log; the v1.0 files are archived with a cover sheet on adoption.
Three kinds of error recur across the three documents and are corrected once here, in Part B, then applied line by line in Parts C–D:
- Mg C written as Mg CO₂e. Carbon mass and CO₂-equivalent mass differ by the factor 44/12 = 3.667. Several lines multiply hectares × Mg C/ha × years and label the result Mg CO₂e without converting.
- Rates applied for 30 years past the point where the stock is exhausted. A loss rate of 0.85 Mg C/ha/yr cannot run for 30 years on a stock that is gone in year 8; a cover-decline rate cannot produce "−55 % cover".
- Programme rules overwritten by the guidance. Credit-type definitions, the number of safeguards principles, and buffer determination are set by MCC-100, the ESS Policy and the Buffer Pool Management Policy. Where the guidance restated them differently, the guidance is corrected to cite the rule.
B. Corrections common to all three guidances
| # | v1.0 text (all three) | v1.1 text | Basis |
|---|---|---|---|
| B1 | "All 9 principles apply" / "9 PRINCIPLES" / "assessing 9 principles" | "All eight safeguards principles of the ESS Policy v1.0 (cl. 0011–0045) apply" | ESS Policy v1.0 cl. 0011 ("eight core safeguards principles"), 0083, 0099 |
| B2 | Buffer stated as "base 20 % + adjustments" with family-specific risk tables and percentages | "The buffer deduction is determined per project by the risk assessment of the Buffer Pool Management Policy v1.0 (cl. 0012–0013, 0047–0049), within the range 10–40 % (MCC-100 v2.2 cl. 0186–0188), verified by the VVB (cl. 0152(h); MCC-400 art. 64). The risk table in this guidance is illustrative of the factors the Policy weighs; it does not set the rate." | K13; PR #130 |
| B3 | Credit-type definitions restated locally (F01 §1: "MCC-HYB ≈ 0.8 tCO₂e + 0.2 fisheries weight"; "MCC-MCU ≈ 1 tCO₂e carbon + SDG benefits") | Deleted. Replaced by: "Credit types are defined in MCC-100 v2.2 cl. 0167 and the Definitions Register v1.0: MCC-CC = one tonne CO₂e removed or reduced (F01); MCC-HYB = one tonne CO₂e plus specified ecosystem co-benefits (F02, F05); MCC-MCU = a unit of non-carbon marine conservation outcome as defined by the methodology (F03, F04), carrying no climate claim." | MCC-100 cl. 0167, 0183.1; Definitions Register v1.0 §1 |
| B4 | "See full methodologies and examples at mcc-registry.org" | "See the approved methodologies at www.marineconservationcredits.com/methodologies and the published rulebook at /transparency/documents" | Domain does not exist; Transparency Policy v1.1 |
| B5 | Claims examples stated locally | "Permitted and prohibited claims are governed by the Claims Policy v1.1; the examples below illustrate it and yield to it." | K6 |
| B6 | Illustrative credit prices ("€5–15/credit", "€2–3/credit") | Deleted from guidance. Price is not a programme parameter and a guidance figure reads as one. | Positioning discipline |
| B7 | Unit-conversion rule not stated | Add to §3 of each: "Convert carbon mass to CO₂-equivalent with 44/12 = 3.667. All credit quantities are stated in t CO₂e (1 Mg = 1 t). Avoided-loss quantities are capped at the measured stock: a loss rate may not be applied beyond the year in which the stock would be exhausted." | Corrects error types 1 and 2 |
C. F01 Blue Carbon Guidance — corrections
C1. §1 credit types (lines "MCC-CC / MCC-HYB / MCC-MCU")
See B3. In addition: F01 methodologies issue MCC-CC only (MCC-100 cl. 0183.1: "MCC-F01 (Blue Carbon — MCC-CC removals)"). The v1.0 statement that an F01 project may select MCC-HYB "when project supports fisheries productivity" is withdrawn; fisheries co-benefits are reported under the SDCF, not encoded in the unit.
C2. §3 Step 5 — leakage arithmetic (the 0.4 % error)
v1.0:
Leakage carbon loss: 50 ha × 3 Mg C/ha/yr × 30 yr = 4,500 Mg C = 16,500 Mg CO₂e Leakage adjustment (divide by project area): 16,500 / 30 yr / 100 ha = 5.5 Mg CO₂e/ha/yr Applied leakage rate: 5.5 / 1,346 = 0.4 % (minimal)
The second division is wrong: 16,500 Mg CO₂e over 30 years is 550 Mg CO₂e per year for the project as a whole. Dividing again by 100 ha produces a per-hectare figure that is then compared with a whole-project annual figure (1,346). The true rate is 550 / 1,346 = 40.9 %, not 0.4 %.
v1.1 (replacement text):
Leakage carbon loss: 50 ha × 3 Mg C/ha/yr × 30 yr = 4,500 Mg C = 16,500 Mg CO₂e over 30 years = 550 Mg CO₂e/yr. Leakage rate: 550 / 1,346 = 41 %. A rate of this size means the design as described is not creditable: leakage above 30 % of gross benefit indicates that the displaced activity, not the project, determines the outcome (cf. the 10–30 % range in §8, Mistake 4). The applicant must redesign the leakage controls before proceeding.
Redesigned case for this example: a leakage management plan (alternative fishing zones agreed with adjacent villages, monitored by transects outside the boundary) reduces the expected unplanned conversion to 5 ha → 5 × 3 × 30 = 450 Mg C = 1,650 Mg CO₂e over 30 years = 55 Mg CO₂e/yr. Leakage is deducted in absolute terms after the uncertainty discount (the discount is not applied to the leakage): After leakage: 1,010 − 55 = 955 t CO₂e/yr.
Consequential changes to Step 6 and the totals (buffer 24 % retained as the illustrative project-specific rate, see B2):
Buffer pool allocation: 955 × 0.24 = 229 t CO₂e/yr · Issuable: 955 × 0.76 = 726 t CO₂e/yr Years 1–10: 7,260 · Years 11–30: 14,520 · 30-year total: 21,780 credits (v1.0: 22,920).
C3. §6 buffer pool example — buffer pool volume
v1.0: "buffer pool contains 9,000 credits as insurance". The chain 1,200 × 0.8 × 0.98 = 941; 941 × 0.29 = 273/yr; × 30 = 8,190. v1.1: "8,200 credits".
C4. §9 worked example (mangrove, MCC-HYB) — four errors
(a) Credit type. "MCC-HYB (carbon + fisheries co-benefit)" → MCC-CC (C1).
(b) Area. The project is 120 ha existing + 20 ha degraded = 140 ha, but Year 30 is computed on "120 ha + 30 ha". v1.1 uses 20 ha throughout.
(c) Baseline stock. "Average baseline carbon: 60 Mg C/ha (mature = 150; degraded = 20; average 70)" is internally inconsistent and averages two stands that are then treated separately. v1.1 states the stands separately: existing 120 ha at 60 Mg C/ha = 7,200 Mg C; degraded 20 ha at 20 Mg C/ha = 400 Mg C; year-0 stock 7,600 Mg C.
(d) The substantive error — crediting growth the project does not cause. v1.0 places the existing 120 ha at 60 Mg C/ha in the baseline and at 150 Mg C/ha ("maintained") in the project scenario. The only project activities described for that stand are protection; nothing in the baseline says it is threatened (the 3 Mg C/ha/yr loss is applied to the 20 ha only). The difference, 90 Mg C/ha × 120 ha = 10,800 Mg C, is therefore not caused by the project and is not additional. It accounts for roughly 70 % of the v1.0 result.
v1.1 replacement quantification (two cases, so the applicant sees what documentation buys):
Case 1 — no documented threat to the existing stand (conservative default).
Baseline year 30: 120 ha stays at 60 Mg C/ha = 7,200; degraded 20 ha continues to lose 3 Mg C/ha/yr and reaches 0 by year 7 → 0. Baseline 7,200 Mg C. Project year 30: 120 ha at 60 Mg C/ha (no claimed change) = 7,200; 20 ha restored to 120 Mg C/ha = 2,400. Project 9,600 Mg C. Net: 2,400 Mg C = 8,800 t CO₂e over 30 years = 293 t/yr gross Uncertainty (90 % CI) ×0.8 → 235 · Leakage 5 % (absolute: 15 t/yr) → 220 · Buffer 25 % → 165 t CO₂e/yr issuable (~4,950 over 30 years)
Case 2 — threat to the existing stand documented (e.g. erosion and cutting at 1 Mg C/ha/yr, evidenced by time-series imagery and stock measurements).
Baseline year 30: 120 ha at 60 − 30 = 30 Mg C/ha = 3,600; degraded 20 ha → 0. Baseline 3,600 Mg C. Project year 30: 120 ha protected at 60 Mg C/ha = 7,200 (avoided loss; no growth claimed without enrichment planting); 20 ha restored to 120 = 2,400. Project 9,600 Mg C. Net: 6,000 Mg C = 22,000 t CO₂e over 30 years = 733 t/yr gross ×0.8 → 587 · leakage 5 % (37 t/yr) → 550 · buffer 25 % → 412 t CO₂e/yr issuable (~12,375 over 30 years)
v1.0's "~1,000 t CO₂e/yr" is withdrawn. The lesson replaces the figure: only change the project causes, on a stand whose baseline trajectory is evidenced, is creditable.
C5. §7 / §11 references
"9 principles" → eight (B1). §11 FAQ on credit prices deleted (B6). Claims examples subordinated to Claims Policy v1.1 (B5).
D. F02 Ecosystem Restoration Guidance — corrections
D1. §3 baseline example — three errors in four lines
v1.0:
Year 30 baseline: 20 % − (2.5 % × 30 years) = −55 % (all coral lost) Baseline carbon loss: 5,000 ha × 0.85 Mg C/ha/yr × 30 yr = 127,500 Mg CO₂e
(a) Cover cannot be negative: at 2.5 %/yr from 20 %, cover reaches 0 % in year 8. (b) 5,000 ha × 0.85 × 30 = 127,500 Mg C, which is 467,500 Mg CO₂e — but (c) the rate cannot run 30 years: once cover is 0 the associated stock is gone, so the avoided loss is capped at the year-0 stock (B7).
v1.1:
Year 30 baseline: cover declines 2.5 %/yr from 20 % and reaches 0 % in year 8; thereafter no further loss is possible. Baseline carbon loss = the measured year-0 organic carbon stock of the reef area, lost by year 8 (not a 30-year rate). Example per hectare: stock 25 Mg C/ha → avoided loss 25 Mg C/ha = 92 t CO₂e/ha, all of it accrued in years 1–8.
D2. §6 worked example (coral reef, 50 ha) — recomputed
v1.0:
Avoided baseline loss: 50 ha × 85 Mg C/ha (mature reef carbon) × 30 yr loss trajectory = 127,500 Mg CO₂e … Issuable credits over 30 years:
42,000 (1,400/year)
A stock (85 Mg C/ha) has been multiplied by 30 years as if it were an annual rate, and labelled CO₂e. The stock of 50 ha at 85 Mg C/ha is 4,250 Mg C = 15,583 t CO₂e in total, and the 85 Mg C/ha figure is for a mature reef, whereas the site is at 15 % cover.
v1.1 (illustrative; the carbon stock must be measured — Monitoring table, "Ecosystem Carbon", ±10 % — and is subject to the Part E determination):
Year-0 stock at 15 % cover, using a linear cover–carbon proxy for the example only: 0.15 × 85 = 12.75 Mg C/ha × 50 ha = 638 Mg C. Baseline: 2 %/yr decline → 0 % cover in year 7.5 → year-30 stock 0. Avoided loss 638 Mg C. Project: recovery to 50 % cover by year 30 → 0.50 × 85 = 42.5 Mg C/ha × 50 ha = 2,125 Mg C. Accumulation above year-0 stock: 2,125 − 638 = 1,487 Mg C. Net vs baseline: 2,125 Mg C = 7,792 t CO₂e over 30 years = 260 t/yr gross 10th-percentile recovery ×0.6 → 156 · uncertainty ×0.8 → 125 · buffer 30 % (illustrative, B2) → 87 t CO₂e/yr issuable (~2,600 over 30 years)
v1.0's "~42,000" is withdrawn (overstatement ≈ ×16). The guidance's own framing — "biodiversity-led, not carbon-volume-led" — is what the corrected number shows; the co-benefit component of MCC-HYB, not the tonne count, carries this family.
D3. §2 and §5
"Additionality demonstrated (restoration would not occur without carbon incentive)" → "…without MCC-HYB credit revenue" (the unit is not a carbon-only instrument). "9 principles" → eight (B1). Mistake 5 "€50,000+ typical" retained as illustrative cost, marked as such.
E. F05 MPA Management Guidance — corrections, and one determination requested
E1. §3 quantification example — unit, rate and label errors
v1.0 lines and corrections:
| v1.0 | Error | v1.1 |
|---|---|---|
| "Baseline carbon loss over 30 years: (100 − 74.5) × 5,000 ha = 127,500 Mg C = 467,500 Mg CO₂e" | correct | unchanged |
| "carbon loss prevented = avoided baseline loss (127,500 Mg CO₂e from above)" | label: the figure is Mg C | "(127,500 Mg C = 467,500 t CO₂e, accruing linearly over years 1–30, not within years 0–10)" |
| "Accumulation: (120 − 100) × 5,000 ha × 20 years = 2 Mg C/ha/yr recovery" | 20 Mg C/ha over 20 years is 1 Mg C/ha/yr | "(120 − 100) Mg C/ha over 20 years = 1 Mg C/ha/yr" |
| "Carbon accumulation: 2 × 5,000 × 20 yr = 200,000 Mg C = 733,000 Mg CO₂e" | follows from the rate error | "1 × 5,000 × 20 = 100,000 Mg C = 366,700 t CO₂e" |
| "Total: 1,200,500 Mg CO₂e over 30 years = 40,000 credits/year" | follows | "467,500 + 366,700 = 834,200 t CO₂e = 27,800 t/yr gross" |
| "×0.75 = 900,000 · ×0.85 = 765,000 · ×0.8 = 612,000 Mg CO₂e credible = 20,400 credits/30 years" | chain follows the wrong total; and 612,000 over 30 years is 20,400 per year, not per 30 years | "×0.75 = 625,650 · leakage ×0.85 = 531,800 · buffer 20 % (illustrative, B2) = 425,400 t CO₂e issuable over 30 years = 14,200/yr" |
Two structural notes added to v1.1 §3: (i) accumulation is measured above the year-0 stock and avoided loss below it; the two do not overlap, but the text must say so; (ii) both are capped by measured stocks and evidenced rates (B7).
E2. §7 worked example (MPA expansion) — units and name
(a) "Expand existing Sargasso MPA" — the Sargasso Sea is in the North Atlantic; the example is in the Coral Triangle. v1.1: "an existing MPA in the Coral Triangle (illustrative)".
(b) Units:
"50,000 ha × 2 Mg C/ha/yr × 30 yr = 3,000,000 Mg CO₂e" → 3,000,000 Mg C = 11,000,000 t CO₂e, and only if the measured sediment/biomass stock in the trawled area is ≥ 60 Mg C/ha (2 × 30); otherwise capped at stock (B7). "50,000 ha × 1 Mg C/ha/yr × 20 yr = 1,000,000 Mg CO₂e" → 1,000,000 Mg C = 3,667,000 t CO₂e Gross: 14,667,000 t CO₂e · ×0.75 = 11,000,000 · ×0.85 = 9,350,000 · buffer 30 % (illustrative) = 6,545,000 t CO₂e over 30 years ≈ 218,000/yr (v1.0: "1.8M … = 60,000 credits over 30 years", which mislabels a 30-year total as annual and understates the CO₂e conversion).
(c) The corrected figure is large enough that v1.1 adds a caution: a 2 Mg C/ha/yr loss rate across 50,000 ha of trawled seabed is an assumption the VVB will test against sediment cores and effort data; the example is arithmetic, not a benchmark.
E3. §5 risk table
Retained as illustrative under B2; "Typical Final Buffer: 33 %" → "the Policy's assessment determines the rate within 10–40 %".
E4. §11 FAQ on enforcement costs and §12 claims
"Carbon revenue (assume €2–3/credit …)" deleted (B6). Permitted claim "This MPA protects X million tonnes of carbon" retained only in the form the Claims Policy v1.1 allows for MCC-HYB, and never as an emission-reduction claim for the stock.
E5. Determination requested from the Standards Committee (Tier 4, MCC-700 §11)
Both F02 (coral reefs) and F05 (reef MPAs) quantify a CO₂e component from reef ecosystems. Reef carbonate (CaCO₃ skeleton) carbon is not a CO₂ removal — calcification releases CO₂ — and the organic carbon pools of a reef (biomass, sediment) are small and poorly characterised relative to blue-carbon habitats. The v1.0 guidances treat "reef ecosystem carbon" as a single stock. Before F02/F05 issue any MCC-HYB unit for a reef site, the Standards Committee should determine which pools are eligible for the CO₂e component (this instrument's working assumption: organic carbon in biomass and sediment only, evidenced by cores; carbonate excluded) and whether M005/M006/M010 require a methodology amendment to say so. Until then, the corrected F02/F05 examples are arithmetic corrections of the v1.0 text, not endorsements of the underlying stock figures.
F. Adoption, consolidation and publication
- Adoption of this instrument by the administration under FD-2026-08-24 item 3, with 14 days' notice via /consultations (Tier 5) — the Part E request goes to the Standards Committee (or the Board acting in its stead, MCC-700 §10.1.1).
- Consolidate the three guidances to v1.1 (docx), applying Parts B–E verbatim; add this instrument as an annex to each; archive v1.0 with a cover sheet stating the errata.
- Publish the v1.1 files on /transparency/documents with SHA-256 (manifest entries), lifting the withholding recorded in PR #131.
- Update
project_f01_to_f05_detailsand the platform's family reference table where they restate v1.0 figures.
Change log — v1.1 DRAFT (25 Aug 2026): first issue.
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