IPCC Biochar Soil Carbon Method
Citation: IPCC (2019). Appendix 4: Method for estimating the change in mineral soil organic carbon stocks from biochar amendments: basis for future methodological development. In 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Vol. 4, Ch. 2. https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch02_Ap4_Biochar.pdf
What it is: The IPCC inventory appendix that set the template for biochar carbon accounting: carbon content by feedstock and process, multiplied by a 100-year permanence factor by production temperature. Later methods, such as models soil GHG from biochar and carbon-credit protocols, build on it.
Key figures
| Figure | Value | Where | Check |
|---|---|---|---|
| Status | A basis for a future Tier 1 method, not complete guidance | Appendix PDF, introduction | ✓ full text |
| Definition of biochar | Solid material from heating biomass above 350 °C under controlled, limited oxidant so it doesn’t combust (pyrolysis or gasification) | Appendix PDF, introduction | ✓ full text |
| Scope | Mineral soils in croplands and grasslands only; not forest land, settlements, other lands, or wetlands; not char from wildfires or open fires | Appendix PDF, introduction and footnote | ✓ full text |
| 100-year permanence factor (F_perm) | High temperature (>600 °C) 0.89 ± 13%; medium (450–600 °C) 0.80 ± 11%; low (350–450 °C) 0.65 ± 15% | Appendix PDF, F_perm table | ✓ full text |
| How F_perm was derived | Two-pool double-exponential model fitted to field and lab datasets longer than one year | Appendix PDF, background | ✓ full text |
| Temperature basis | Adjusted to 20 °C ambient, conservative against a ~10 °C average land surface temperature | Appendix PDF, background | ✓ full text |
| Carbon content (F_Cp) | From Neves et al. (2011) regressions, corrected for ash using yields from Woolf et al. (2014) | Appendix PDF, Table 4Ap.1 notes | ✓ full text |
| Shorter horizons | Estimating carbon remaining over less than 100 years needs more detailed information | Appendix PDF, footnote | ✓ full text |
Use with care
- models soil GHG from biochar re-derived temperature-specific factors, and its values (0.63 / 0.71 / 0.82 at 14.9 °C) are lower than this table’s. Don’t mix the two tables in one calculation.
- This is inventory guidance, not a crediting standard. See Permanence Science for Credits for how credit programs use or depart from it.
Related: CDR Potential and IPCC Accounting · Permanence · Woolf IPCC Fperm · Key Sources