Biochar

Quantitative Benchmarks

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Quantitative Benchmarks

Cross-source cheat sheet. Each figure’s checked home is its source note (index in Key Sources); if a number here disagrees with a source note, the source note wins. Do not invent figures beyond these sources.

Carbon permanence (F_perm / % remaining)

SourceFinding
IPCC 2019 App. 4 · estimates soil C stock change from biochar100-yr F_perm: 0.65 / 0.80 / 0.89 (low/med/high T)
models soil GHG from biochar (DOI)At 14.9 °C: 100-yr ≈ 0.63 / 0.71 / 0.82; 1000-yr high-T ~0.25
reviews biochar climate mitigation (DOI)H/C_org < 0.5 subset: mean ~82% remaining at 100 yr (95% of cases >50%); not re-checked against the paywalled full text
EBC / IBIH/C_org ≤ 0.7; O/C_org often ≤ 0.4

Crop yields

SourceEffect
meta-analyzes crop productivity (DOI)Mean ~+10% (−28% to +39%)
compares tropical vs temperate yields (Environ. Res. Lett. 12:053001)Stronger in tropics
global GHG and yield patterns (DOI)+9.4%
Field synthesis 2022 (Renew. Sustain. Energy Rev.)+15.7% (cite via science report; confirm publisher page before diligence)

GHG fluxes

GasBenchmark
N₂Ometa-analyzes N2O mitigation −54% (lab and field studies from 2007–2013; DOI); global GHG and yield patterns −26.8% (incubation, pot and field pooled; DOI); models soil GHG from biochar field-trial fit −23%, first year only
CH₄Jia 2023 −13.0%; mixed/paddies study-dependent
Primingmeta-analyzes stability and priming (DOI) mean SOC mineralization −3.8% (CI crosses zero; negative in studies under six months, +20.8% in sandy soils); Weng 2017 decade-scale accrual

CDR / mitigation (Gt or Pg CO₂e yr⁻¹)

SourceEstimate
reviews biochar climate mitigation (DOI)3.4–6.3 (abstract); up to 7.4–10.3 with land-sparing or CCS pathways (full text, not re-checked)
Weng & Cowie 2025Literature 0.03–11; multi-Gt credible
Fuss & Lunstrum 2026 / State of CDR · CDR costs and potentialsRemoval ≤~2.7; total mitigation ≤~10.3; IAM 2050 <0.1–1.1
Costs (State of CDR / recent reviews)~$70–360/tCO₂ (Fuss & Lunstrum 2026)

Carbon fraction (Woolf 2021 examples)

  • Wood pyrolysis mean FC ≈ 0.76; high-T wood ≈ 0.81 (Woolf et al. 2021)
  • Manure ≈ 0.39; sewage sludge ≈ 0.37
  • Gasification sludge/manure ~0.10–0.14

Application rates

  • Research: ~5–50+ t ha⁻¹ (sometimes 100; Jeffery 2011 extremes)
  • Nutrient-enriched fertilizers: <2 t ha⁻¹
  • Woolf 2021 N₂O credit: only >10 Mg C ha⁻¹ year 1

Graph View

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