Wool

Material Composition Assumptions

The default CCI score covers clean (scoured) wool fibre, representing the functional unit of 1 kg of processed wool ready for spinning. The production chain modelled includes:

• Sheep farming: Grazing on pasture, supplementary feed, and animal husbandry inputs. Enteric methane from ruminant digestion is the dominant emission source and is classified as Scope 1 in the context of the wool processing supply chain (Scope 3 from the brand/retailer perspective).
• Wool scouring: Hot-water washing to remove lanolin, suint, and vegetable matter. Energy- and water-intensive; typically performed in Australia, New Zealand, or China.
• Carbonising and combing: Chemical treatment to remove vegetable matter; top-making for worsted processing.
• Dyeing and finishing: Application of dyes, shrink-resist treatments (e.g., chlorine-Hercosett for machine-washable wool), and softening agents.
• Spinning: Ring or open-end spinning into yarn for subsequent weaving or knitting.

Wool fibre is approximately 97-98% pure protein (keratin) by mass. Lanolin yield (15-25% of raw fleece mass) is a co-product and may generate a small system expansion credit in detailed LCAs, but is excluded from the default conservative estimate.

Manufacturing Geography

The default manufacturing region reflects the global supply chain structure for wool:

• Farm origin: ~80% of apparel-grade fine wool (merino) originates in Australia and New Zealand. UK and Falkland Islands produce coarser British breeds.
• Scouring and early processing: Increasingly concentrated in China (particularly Zhejiang province), which processes an estimated 40-50% of global raw wool. Some scouring remains in country of origin (Australia, New Zealand).
• Spinning and fabric production: Primarily China, with significant secondary production in Italy (for luxury worsted) and India.

The default grid intensity of ~700 gCO2e/kWh reflects Chinese provincial grids in major textile-processing regions, which are more coal-intensive than the national average. Italian and UK processing facilities would use lower-intensity grids (~230 and ~210 gCO2e/kWh respectively), resulting in materially lower Scope 2 emissions.

Regional Variation

Processing Region	Grid Intensity	Estimated Score Adjustment
China (default)	~700 gCO2e/kWh	Baseline
Australia / New Zealand	~590 gCO2e/kWh	-15% on Scope 2 (saves ~0.6 kgCO2e)
EU average	~300 gCO2e/kWh	-57% on Scope 2 (saves ~2.3 kgCO2e)
Italy (luxury worsted)	~230 gCO2e/kWh	-67% on Scope 2 (saves ~2.7 kgCO2e)
UK	~210 gCO2e/kWh	-70% on Scope 2 (saves ~2.8 kgCO2e)

Note: Because Scope 3 (feed, land use, enteric methane) dominates at ~65% of total emissions, regional grid variation has a proportionally smaller effect on the total score than in more electricity-intensive categories.

Provenance Override Guidance

A supplier or manufacturer may override the default CCI score by submitting:

1. Certified LCA or Product Carbon Footprint (PCF) per ISO 14067 or PAS 2050, covering farm-gate through yarn or fabric stage with audited methane and land-use figures.
2. Farm-level methane data: Certified pastoral management practices (e.g., improved pasture species, selective breeding for low-methane sheep) supported by NZAGRC or equivalent methodology.
3. Scouring facility energy data: Utility bills or renewable energy certificates (RECs/GOs) for the scouring plant with regional grid-emission factor.
4. Dyeing process certification: GOTS (Global Organic Textile Standard) or bluesign certification with audited wastewater treatment and energy records.
5. Responsible Wool Standard (RWS) or ZQ Merino certification may support reduced land-use emission claims if aligned with a recognized LCA methodology.

Methodology Notes

• CCI score of 25 kgCO2e/kg represents a mid-range estimate consistent with published LCA literature for scoured merino wool. The CSIRO Wiedemann et al. range of 24-27 kgCO2e/kg clean wool (including farm-gate land use) is used as the primary anchor.
• Scope breakdown: Scope 3 dominates at 64% (16 kgCO2e), comprising primarily feed production, pasture management, and upstream logistics. Scope 1 is 20% (5 kgCO2e), driven almost entirely by sheep enteric methane from ruminant digestion — a biogenic methane source with a GWP100 of 28 (AR5) or 27.9 (AR6). Scope 2 is 16% (4 kgCO2e) from scouring and dyeing electricity consumption.
• Functional unit: 1 kg of clean (scoured) wool fibre, cradle to gate (farm through yarn). Downstream garment assembly and consumer use are excluded.
• Land use: Wool grazing systems typically involve low-intensity extensive pasture in semi-arid environments. Land use change emissions are modest compared to soy or beef but are included in the Scope 3 estimate for completeness.
• Data gaps: Methane intensity varies significantly by breed, diet, and pasture management system. Farm-level variation of ±30-50% around the mean is common in peer-reviewed literature. This uncertainty is reflected in the medium confidence rating.
• Comparison context: Wool’s footprint (~25 kgCO2e/kg) is substantially higher than cotton (~8-10 kgCO2e/kg) and conventional polyester (~5.5 kgCO2e/kg) on a per-kg basis. However, wool garments typically have longer service lives and may require less frequent washing, partially offsetting the production-phase differential on a per-wear basis.