IPCC AFOLU Tier-1 Emission Factors — Complete Reference Dataset

AFOLU Tier-1 emission factors are the IPCC’s global and regional default values for agriculture, forestry and other land use — the numbers a country or company reaches for when it has no measured, farm-specific data of its own. They cover livestock methane, nitrous oxide from managed soils, methane from flooded rice, CO₂ from liming and urea, carbon-stock losses from land-use change, and emissions from drained organic soils and biomass burning. This page is the frozen, citable snapshot of every default GreenCalculus carries in the MasterBrain afolu section (v2026.110 (2026-08-08)), verified cell-by-cell against the published IPCC tables.

This parent set is split into eight sub-datasets, each published in full: enteric fermentation, manure management, agricultural soils N₂O, rice cultivation, forest land & harvested wood, land-use change, wetlands & drained organic soils, and biomass burning.

What AFOLU Tier-1 emission factors are

AFOLU — Agriculture, Forestry and Other Land Use — is the sector of a national or corporate greenhouse-gas inventory that covers biological and land-based sources and sinks: livestock, fertilised and grazed soils, rice paddies, forests, peatlands, and the burning of biomass. Because these sources are diffuse and biologically variable, the IPCC publishes its methods at three levels of rigour, the tiers:

• Tier 1 — apply a single global or broad-regional default emission factor to readily available activity data (head of cattle, kg of nitrogen applied, hectares of rice). Lowest data demand, highest uncertainty. This dataset is the Tier-1 default set.
• Tier 2 — substitute country-specific factors (e.g. nation-level enteric methane derived from local feed intake and digestibility) into the same equations.
• Tier 3 — process-based models or direct measurement, parameterised to the reporting entity.

Tier 1 exists so that any reporter can produce a complete, methodologically defensible inventory before investing in country data. Under the IPCC “key category” principle and GHG Protocol guidance, an entity should move to Tier 2 or 3 for the sources that dominate its footprint, and may legitimately keep Tier 1 for minor sources. The factors here are the same defaults that drive the GreenCalculus FLAG emissions calculator and the fertiliser & soil N₂O calculator.

Headline defaults at a glance

The three IPCC sources combined here

The afolu dataset draws on three IPCC publications. The 2006 Guidelines are the foundation; the 2019 Refinement updates a defined set of soil-N₂O and livestock factors; the 2013 Wetlands Supplement adds drained and rewetted organic-soil factors that the 2006 Guidelines did not cover. Where the 2019 Refinement updated a value, this dataset carries the refined value and labels its provenance accordingly.

A practical consequence of the 2019 Refinement matters for anyone reconciling totals: several headline coefficients changed. Direct synthetic-fertiliser N₂O in wet climates rose from the single 2006 default of 0.01 to a disaggregated 0.016 kg N₂O-N/kg N; the leaching fraction FracLEACH fell from 0.30 to 0.24; and the leaching emission factor EF5 rose from 0.0075 to 0.011. Mixing 2006 and 2019 coefficients inside one calculation produces a number that traces to neither vintage. See the fertiliser & soil N₂O methodology for the full reconciliation.

What the 2019 Refinement changed

Livestock — enteric fermentation (CH₄)

Enteric fermentation is the digestive methane produced by ruminants. The Tier-1 default is an annual emission factor per head, in kg CH₄/head/yr. Non-cattle species use a single value (Table 10.10); cattle and buffalo are disaggregated by world region (Table 10.11) because intake — and therefore methane — scales with productivity. To convert to CO₂e, multiply by the AR6 GWP-100 for biogenic methane, 27.9 (see the IPCC AR6 GWP reference dataset); livestock CH₄ is biogenic, not fossil.

Cattle and buffalo are the dominant enteric source and are regionalised. The table below gives the Tier-1 per-head defaults by IPCC world region for dairy cattle, other (non-dairy) cattle, and buffalo. Where a herd spans systems, the 2019 Refinement also publishes a Tier-1a split by high/low productivity within each region.

All values kg CH₄/head/yr. Source: IPCC 2006 GL Vol 4 Ch 10, updated by the 2019 Refinement, Tables 10.10 & 10.11. Uncertainty ±30–40% (Section 10.3.4). Buffalo are not reported by IPCC for North America or Oceania.

Manure management — CH₄ and N₂O

Stored manure emits methane (from anaerobic decomposition of volatile solids) and both direct and indirect nitrous oxide (from nitrification/denitrification and from volatilised then redeposited nitrogen). Methane from manure is strongly temperature-dependent: the same manure in a warm climate emits far more than in a cool one, because the IPCC methane conversion factor (MCF) rises with temperature. The Tier-1 per-head defaults below are annual averages weighted across a region’s typical animal-waste-management systems (AWMS).

Per-head manure CH₄ stored under afolu.manure_ch4.<species>.tier1.global as CO₂e (× AR6 GWP-100, biogenic CH₄ = 27.9): dairy cattle 864.9, pigs 390.6 kg CO₂e/head/yr. Species-level system-and-climate defaults (g CH₄/kg volatile solids, IPCC Table 10.14) are available in the full dataset for entities applying the volatile-solids method rather than the per-head shortcut.

Indirect manure N₂O depends on how much manure nitrogen volatilises as ammonia and NOₓ, which is set by the management system (FracGas_MS, Table 10.22). The volatilised nitrogen is later converted to N₂O at the indirect emission factor EF4 (see §5). Climate dependence here is weak; system choice dominates.

Source: IPCC 2006 GL Vol 4 Ch 10 Table 10.22, Frac_{Gas_MS} column, Dairy Cow. The full dataset carries every species × system cell.

Managed soils — direct & indirect N₂O

Nitrous oxide from managed soils is the largest agricultural N₂O source and the most error-prone to compute, because it runs along two pathways. The direct pathway emits N₂O at the point of application (EF1, EF1FR, EF2, EF3_PRP). The indirect pathway accounts for nitrogen that first leaves the field — as volatilised ammonia/NOₓ (Frac_GASF/Frac_GASM, re-deposited and emitting at EF4) or as leaching/runoff (Frac_LEACH, emitting at EF5). All emission factors below are expressed as kg N₂O-N; convert to N₂O by × 44/28, then to CO₂e by × 273 (AR6 GWP-100 for nitrous oxide).

Liming, urea application & rice cultivation

Three further direct sources round out cropland accounting. Liming and urea application release CO₂ as the carbonate or amide carbon hydrolyses in the soil; their emission factors are carbon-content fractions. Rice cultivation emits methane from flooded paddies, built up from a baseline daily emission factor (EFc) scaled by water regime, pre-season practice, and organic amendments, then multiplied by the cultivation period.

Carbon-content EFs become CO₂ by × 44/12: limestone 0.12 t C = 0.44 t CO₂ per tonne; urea 0.20 t C = 0.733 t CO₂ per tonne. The full dataset holds the regional rice EFc set (North America 0.65, South Asia 0.85, Africa 1.19, Southeast Asia 1.22, South America 1.27, East Asia 1.32, Europe 1.56 kg CH₄/ha/day) and the SFw water-regime scaling factors (continuous flooding 1.0, single drainage 0.71, multiple drainage 0.55, regular rainfed 0.54, upland 0).

Land-use change & carbon removals

Land-use change releases the carbon stored in cleared biomass and soil; mature and restored ecosystems remove carbon. GreenCalculus carries these as Tier-1 CO₂e aggregates (IPCC AR6 WGI defaults) for the FLAG and land-sector calculators. Deforestation factors are one-time stock losses on conversion; removals are annual fluxes (shown negative). These are deliberately CO₂e-aggregate rows — gas and GWP set are null because the IPCC publishes them already aggregated.

Drained organic soils & wetlands

Drained peat and other organic soils are an outsized emissions source per hectare, which is why the 2013 Wetlands Supplement added dedicated factors absent from the 2006 Guidelines. CO₂ factors are expressed as tonnes of carbon per hectare per year (× 44/12 for CO₂); CH₄ and N₂O are direct gas fluxes.

The full dataset also carries dissolved-organic-carbon (DOC) drainage factors (e.g. temperate EF_DOC 0.31 t C/ha/yr) and coastal-wetland rewetting factors (tidal marsh, mangrove, seagrass) from Wetlands Supplement Ch 2 & 4.

Biomass & crop-residue burning

Burning vegetation and crop residues emits CH₄ and N₂O (the inventory-relevant non-CO₂ gases; biogenic CO₂ from burning is reported but not counted as a net anthropogenic source where the biomass regrows). Emission factors are grams of gas per kilogram of dry matter burnt, applied to the mass of fuel actually combusted — which is the fuel load × the combustion factor (Cf, e.g. 0.80 for agricultural residues, Table 2.6).

All values g per kg dry matter burnt. Source: IPCC 2006 GL Vol 4 Ch 2 Table 2.5.

Application — formulas & worked examples

AFOLU Tier-1 calculations follow the pattern activity data × emission factor × GWP, with the gas-specific GWP-100 from IPCC AR6: biogenic CH₄ = 27.9, N₂O = 273, CO₂ = 1. Stoichiometric conversions (N₂O-N → N₂O × 44/28; C → CO₂ × 44/12) are applied before the GWP step.

Soil-N₂O worked in full: 100,000 kg synthetic N × EF1 0.016 = 1,600 kg N₂O-N → ×44/28 = 2,514 kg N₂O → ×273 ≈ 686 t CO₂e. With the aggregated EF1 = 0.01 instead, the same 100 t N yields ≈ 429 t CO₂e — the disaggregated-vs-aggregated EF1 choice changes the result by 60%, so disclose which you used.

Framework requirements

AFOLU Tier-1 factors are accepted or mandated across the principal inventory and disclosure frameworks, almost always with the proviso that the reporter discloses the tier and moves to higher tiers for key categories.

Common reporting errors

1. Using a Tier-1 default where Tier-2 country data exists. For a key category, IPCC and the GHG Protocol expect the country/entity factor. Defaulting to Tier 1 to save effort understates or overstates a material line and is an audit finding.
2. Applying the wrong climate zone. Tropical EF2 (16 kg N₂O-N/ha/yr) is double the temperate value (8); wet-climate EF1 (0.016) is over three times the dry value (0.005). Climate-zone misassignment is the single largest Tier-1 error.
3. Double-counting biogenic CO₂. CO₂ from biomass burning or livestock respiration where the biomass regrows is reported as a memo item, not added to the net anthropogenic total. Only CH₄ and N₂O from these sources count.
4. Ignoring the indirect N₂O pathway. Reporting only direct EF1 and omitting volatilisation (Frac_GASF/EF4) and leaching (Frac_LEACH/EF5) understates fertiliser N₂O by roughly a third.
5. Mixing 2006 and 2019 coefficients. Pairing a 2019 disaggregated EF1 with a 2006 Frac_LEACH = 0.30 (rather than 0.24) produces a total that traces to neither vintage. Pick one refinement set and apply it throughout.
6. Applying livestock EFs without regional adjustment. Dairy cattle range from 73 (Indian Subcontinent) to 138 (North America) kg CH₄/head/yr. Using the wrong region nearly doubles or halves the estimate.
7. Netting removals against emissions. A forest removal of −11,000 kg CO₂e/ha/yr must be reported on its own line, not subtracted from gross emissions, under land-sector guidance.
8. Using the fossil-CH₄ GWP for livestock. Enteric and manure methane are biogenic (GWP-100 = 27.9), not fossil (29.8). The 6.8% difference compounds across a large herd.

Methodology, boundaries & uncertainty

Rounding & precision

Every value is reproduced at the IPCC’s published precision — 0.016 is not rounded to 0.02, 27,900 to 28,000, or 1.19 to 1.2. Where a value is stored in MasterBrain as a CO₂e aggregate (livestock per-head, land-use change, removals), the underlying gas-and-GWP basis is documented in the row note and reproduced in the section footnotes here.

Climate-zone dependence

Many AFOLU factors are split by climate (wet/dry, temperate/tropical, boreal). The disaggregated value is more accurate where the zone is known; the aggregated value is the fallback. This dataset carries both, clearly labelled, and the calculators expose the choice.

Uncertainty

IPCC Tier-1 AFOLU uncertainty ranges are wide: roughly ±30–50% for enteric and manure methane, a factor-of-two order for managed-soil N₂O emission factors, and large ranges for land-use-change stock factors. Tier 1 is a screening-grade estimate; report it as such and prioritise key categories for higher-tier methods.

Geographic applicability

Regional defaults (cattle, buffalo, rice) apply to the IPCC world region named, not to any single country within it. National Tier-2 factors, where published, supersede these defaults locally.

What is excluded

This dataset does not contain Tier-2 or Tier-3 country-specific factors, full Tier-2 livestock characterisation parameters beyond the published Annex defaults, or harvested-wood-product (HWP) accounting (which is a stock-change method, not an emission factor). It is the Tier-1 default layer only.

Implementation & provenance chain

1. Primary source — the IPCC 2006 Guidelines Vol 4 (AFOLU), the 2019 Refinement, and the 2013 Wetlands Supplement, read at the table and equation level (each row records its source.cell_ref, e.g. “Vol 4 Ch 10 Table 10.11”).
2. MasterBrain afolu rows — each factor is stored as a canonical row with key, value, unit, gas, GWP set, source id and cell reference. The version stamp is dynamic: v2026.110 (2026-08-08).
3. REST API — rows are exposed read-only at the public factors endpoint (§15), the same data this page is verified against.
4. CSV — a flat machine-readable export of the same rows for spreadsheet and data-science use.
5. Live calculators — the FLAG emissions calculator and fertiliser & soil N₂O calculator read these factors at runtime and emit an audit trail naming the row, value and source.
6. Update plan — when the IPCC issues a further refinement, the affected afolu rows are updated in MasterBrain, the MB version increments, and this page’s version history records the change. The frozen tables above are re-verified before any value is altered.

Data access — REST API and CSV

The AFOLU factor set is published as IPCC source-derived reference data, reproducible with attribution. The endpoint exposes the verified factor rows; it does not expose the proprietary curation, blends, and methodology mappings that sit elsewhere in MasterBrain.

REST API (JSON)

Query the live factors endpoint, filtered to the afolu section:

/wp-json/greencalculus/v1/factors/afolu?limit=500

Open API endpoint →

Each row returns key, name, factor (value, unit, gas, GWP set, uncertainty), source (id, cell_ref, retrieved) and scope.

CSV (flat dataset)

A flat CSV of every AFOLU factor — key, value, unit, gas, GWP set, source, cell reference — for direct import.

Cite this dataset

Cite the IPCC primary sources for the factor values. The GreenCalculus compilation reference is optional and points to the machine-readable, version-stamped archive.

Frequently asked questions

Version history

Primary source. IPCC (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4 (AFOLU); IPCC (2019) 2019 Refinement to the 2006 IPCC Guidelines; IPCC (2014) 2013 Supplement: Wetlands. IGES, Japan. IPCC material is reproducible with attribution.

GreenCalculus implementation. MasterBrain v2026.110 (2026-08-08); values verified cell-by-cell against the IPCC AFOLU source tables and the MasterBrain afolu rows by Jeremiah Say, June 2026. Tier-1 defaults reproduced at published precision; aggregated and disaggregated variants both retained and labelled.

Disclaimer. Published for reference and calculation. Tier-1 defaults are screening-grade global/regional averages with wide uncertainty; verify the tier, climate zone and vintage required by your reporting framework, and move to Tier 2/3 country factors for key categories before finalising an inventory.

This dataset is published as part of MasterBrain — the GreenCalculus open emission-factor database, anchored to the IPCC, GHG Protocol, DEFRA and Ember. MasterBrain v2026.110 (2026-08-08) →