CSI Global Biochar C-Sink
Operator: Carbon Standards International AG (CSI), with science authorship by the Ithaka Institute (formerly framed as “EBC Biochar C-Sink”)
Registry: Global C-Sink Registry
Current industrial standard: Global Biochar C-Sink Standard 3.3 (valid since 9 June 2026); prior v3.2 from 15 November 2025
PDF: 4000039EN.pdf
Formulas & EFs: 4000115EN.pdf
This note is the map of the CSI biochar C-sink cluster. Child notes hold overview history, GPC/SPC permanence, and MRV / emission portfolio. Research dump: /workspace/biochar-research/csi-c-sink-deep-dive.md (2026-09-16).
Cross-standards: Verra vs Isometric vs Puro · Puro vs Other Standards · Verra VM0044 · Isometric Biochar Protocol · Puro.earth Overview · Product Standards EBC IBI
Why it matters for biochar
CSI sits at the intersection of product certification (EBC/WBC) and C-sink accounting. It does not issue a classic multi-sector offset unit; it certifies tracked biochar C-sinks split into:
| Pool | Meaning (v3.3) | Typical climate use |
|---|---|---|
| GPC | Geologically persistent carbon (>1000 years) | CO₂ / N₂O offsetting under CSI logic |
| SPC | Semi-persistent carbon (decays over ≤1000 years) | Temporary climate services; CH₄ offsetting via TCE |
That GPC/SPC split — plus an upper persistence class unlocked by Ro ≥ 3.8% or BC_HyPy ≥ 90% — is CSI’s distinctive permanence story relative to Puro’s CORC200+ centuries claim and Verra’s 100-year Table 3 factors. See CSI GPC vs SPC Permanence Classes · Permanence Science for Credits.
Related: Biochar as Durable CDR · MRV Stack · Carbon Markets Hub · Contaminants and Quality
Cluster map
| Note | Role |
|---|---|
| CSI Global Biochar C-Sink (this page) | Hub / version / what is credited / link map |
| CSI Overview | CSI org, registry, Artisan, EU CS-BCR, ICVCM |
| CSI GPC vs SPC Permanence Classes | Persistence classes, Ro/HyPy, CINK_H, materials |
| CSI MRV and Emission Portfolio | Emission portfolio, MoS, fossil plan, dMRV, applications |
| Product Standards EBC IBI | EBC/WBC prerequisite (Policy) |
| Puro vs Other Standards · Verra vs Isometric vs Puro | Choosers |
Prerequisite: EBC / WBC
Only EBC- or WBC-certified biochar may receive Global Biochar C-Sink certification. Product class must match use (e.g. EBC-Agro / WBC-Agro for agricultural soil). Persistence analytics beyond the EBC Basic package (Ro, HyPy) must be requested as part of the same EBC/WBC batch analysis — separate sampling is not accepted (v3.3 §1.3).
Deepen: Product Standards EBC IBI · EBC Standard 10.5E PDF · EBC service · WBC service
Persistence classes (v3.3 snapshot)
| Condition | Split |
|---|---|
| H/C_org > 0.40 | 100% SPC, 0% GPC |
| H/C_org ≤ 0.40 (lower class) | 75% GPC / 25% SPC |
| Upper class: mean Ro ≥ 3.8% (distributional guards) or BC_HyPy ≥ 90% | 90% GPC / 10% SPC |
Full criteria, example Table 2, SPC decay formula, and materials rules: CSI GPC vs SPC Permanence Classes.
Emission portfolio (snapshot)
All associated GHG from biomass → application must be registered and offset before C-sink validation (v3.3 Ch. 4):
- Fossil CO₂ / N₂O → offset with GPC
- CH₄ → temporary sinks delivering equal TCE within 5–20 years
- Margin of safety 20 kg CO₂e / t biochar (DM), factory gate
- Energy-use efficiency >60%; fossil process emissions plan toward <100 kg CO₂e / t biochar by 2030 and <20 kg by 2035 (exec summary wording — see MRV note for §4.5 “biochar-carbon” variant)
Detail: CSI MRV and Emission Portfolio.
Sibling tracks (not this industrial PDF)
| Track | Role | Link |
|---|---|---|
| Global Artisan C-Sink v2.1A | Distributed / Kon-Tiki production in World Bank LMIC+UMIC | service · PDF |
| CS-BCR (draft 0.7) | EU CRCF permanent biochar removals under Reg. 2024/3012 + Delegated Reg. 2026/285 | PDF; consult 26 Aug–24 Sep 2026 on service page |
Context: CSI Overview.
Integrity (ICVCM) — research date 2026-09-16
| Layer | Status |
|---|---|
| Program | Global C-Sink Standards submitted (application 1 Apr 2026; PDF). ICVCM assessment-status table shows submission in process — treat as not CCP-Eligible yet |
| Biochar method CCP | CSI not among CCP-Approved biochar rows (those include Verra VM0044 v1.2, Isometric Biochar 1.0, CAR). Confirm live: ICVCM assessment status |
Buyer implication: CCP-methodology-labelled BCR today still clears mainly through Verra VM0044 / Isometric Biochar Protocol until CSI finishes program + category assessment. See Puro vs Other Standards · Risks and Controversies.
Version timeline
| Date | Event | Source |
|---|---|---|
| 2020 | EBC C-Sink published (first biochar / early geological C-sink cert) | service page |
| Jun–Jul 2024 | Global Biochar C-Sink published; applications from 1 Jul 2024 | service page |
| Oct 2024 / 1 Jun 2025 | v3.0 published; valid for certified companies from Jun 2025 | v3.2 imprint |
| 15 Nov 2025 | v3.2 valid | 4000183EN |
| 9 Jun 2026 | v3.3 valid (upper class Ro/HyPy; AR6 CH₄ GWP) | 4000039EN |
| Draft v4.0 | Public consultation closed 30 Apr 2026 — draft only; v3.3 remains live | service page; 4000253EN |
When to prefer CSI (compressed)
Prefer CSI when EBC/WBC is already in-stack, GPC/SPC + millennial GPC narrative (or Artisan geography) matters, and/or EU CS-BCR / CRCF is the commercial path. Prefer Verra/Isometric/Puro when CCP method labels, public CORC indexes, or non-EBC MRV cultures dominate. Full chooser: Puro vs Other Standards · Verra vs Isometric vs Puro.
Primary links
- Global Biochar C-Sink 3.3 PDF
- Formulas & emission factors
- Matrix positive list
- CSI service page
- Global C-Sink Registry
- EBC · Ithaka
- CS-BCR 0.7 PDF
- EU Delegated Reg. 2026/285
- ICVCM CSI application
- Schmidt et al. 2025 — https://doi.org/10.1111/gcbb.70092
- Sanei et al. 2024 — https://doi.org/10.1016/j.coal.2023.104409