CDR Potential and IPCC Accounting
IPCC inventory method
IPCC 2019 Refinement Vol. 4 Appendix 4 provides a method for estimating biochar C in mineral cropland/grassland soils (PDF · estimates soil C stock change from biochar).
F_perm after 100 years (conservative ~20 °C basis in appendix notes):
| Temperature class | F_perm |
|---|---|
| Low (350–450 °C) | 0.65 |
| Medium (450–600 °C) | 0.80 |
| High (>600 °C / high-T gasification) | 0.89 |
Uncertainty roughly ±11–15%. Guidance / basis for future Tier 1—not a credit methodology. See Verra VM0044, Puro CORC200+, etc. for market methods.
models soil GHG from biochar extends this with H/C_org and soil-temperature predictors. DOI: 10.1021/acs.est.1c02425.
Mitigation / CDR potential estimates
| Source | Estimate |
|---|---|
| Woolf et al. 2010 | Max 1.8 Pg CO₂-Cₑ yr⁻¹ (≈ ~6.6 Pg CO₂e if ×44/12); century total 130 Pg CO₂-Cₑ. Prefer reviews biochar climate mitigation / Weng 2025 for updated framing. |
| Lehmann et al. 2021 | Emission reductions 3.4–6.3 Pg CO₂e yr⁻¹ (~half CDR); residues-only 2.4–3.9; with land sparing + CCS up to ~7.4–10.3 |
| Weng & Cowie 2025 | Literature 0.03–11; credible multi-Gt scale |
| State of CDR 2026 (Fuss & Lunstrum) · CDR costs and potentials | Sustainable removal ≤~2.7 GtCO₂ yr⁻¹; total mitigation ≤~10.3; IAM 2050 <0.1–1.1 |
| Costs (Fuss & Lunstrum 2026) | Often ~10–345 |
LCA / system boundaries
Net climate benefit is dominated by biochar C permanence vs baseline biomass fate, modulated by methane avoidance (rice, landfill), energy co-products, transport, and kiln CH₄ if poorly engineered (Roberts et al. 2010 onward; Matuštík et al. 2020 review; Lehmann 2021).
State of CDR (2026) and Weng & Cowie (2025) place biochar as largest current novel CDR contributor with gigaton-scale technical/sustainable potential but much lower near-term economic/IAM deployment.
MRV accounting insight (science side)
MRV can focus on mass produced × C fraction × permanence factor at the kiln/gate, with application verification—cheaper than full soil flux monitoring (Lehmann 2021). Markets implement this differently—see MRV Stack.
Primary links / Citations
- Lehmann et al. (2021). DOI: 10.1038/s41561-021-00852-8
- Woolf et al. (2010). DOI: 10.1038/ncomms1053
- Weng & Cowie (2025). DOI: 10.1038/s43247-025-02228-x
- Fuss & Lunstrum (2026). DOI: 10.17605/OSF.IO/FBZ4X