Shipping Packaging — Corrugated Cardboard

Material Composition Assumptions

The default reference product is 1 kg of single-wall corrugated cardboard (C-flute), composed of:

• Linerboard (top and bottom): Two layers of kraft linerboard or testliner, each approximately 125-200 g/m². Kraft linerboard uses predominantly virgin softwood fiber; testliner uses recycled fiber.
• Fluting medium: Corrugated medium (wave-shaped inner layer), typically 90-150 g/m², made from semi-chemical or recycled pulp.
• Starch adhesive: Corn or wheat starch adhesive bonding the fluting to the liners, approximately 5-15 g/kg of board.
• Recycled content: Global average recycled content in corrugated board is approximately 50-60% in Europe and 30-50% in the USA. The default score uses a blended virgin/recycled scenario.

Corrugated board is the most widely used shipping packaging material globally, with approximately 160 million tonnes produced annually. The kraft pulping process (digesting wood chips in sodium hydroxide and sodium sulfide) is the primary manufacturing method and is energy-intensive but increasingly uses black liquor (a by-product) as biomass fuel.

Manufacturing Geography

Corrugated packaging is produced regionally due to its bulk and low value-to-weight ratio:

• USA: World’s largest corrugated producer. Mills concentrated in the Southeast (pine forests) and Midwest. Average recycled content ~40%.
• China: Second-largest producer, with growing domestic demand driven by e-commerce. Higher reliance on recycled fiber (formerly imported OCC).
• EU: Germany, Sweden, Finland, and France are major producers. EU average recycled content ~65%.
• Grid intensity (USA): 390 gCO2e/kWh (IEA 2024).
• Grid intensity (China): 565 gCO2e/kWh (IEA 2024).
• Rationale: Pulp and paper mills are among the most energy-intensive manufacturing facilities, but the kraft process generates significant biomass energy from black liquor combustion. Many mills are 50-70% energy self-sufficient. Grid electricity is primarily used for paper machine drives and corrugating equipment.

Regional Variation

Manufacturing Region	Grid Intensity	Estimated Score (per kg)	Adjustment vs Default
USA (default)	~390 gCO2e/kWh	1.3 kgCO2e	Baseline
China	~565 gCO2e/kWh	1.5 kgCO2e	+15%
EU average	~300 gCO2e/kWh	1.0 kgCO2e	-23%
Sweden/Finland	~30 gCO2e/kWh	0.7 kgCO2e	-46%
India	~708 gCO2e/kWh	1.7 kgCO2e	+31%

Note: Recycled content is as influential as grid intensity. 100% recycled corrugated board typically has 20-40% lower cradle-to-gate emissions than virgin-fiber board, independent of grid effects.

Provenance Override Guidance

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

1. Environmental Product Declaration (EPD) per EN 15804 or ISO 14025 for the specific corrugated board product.
2. Recycled content certification: Verified recycled content percentage (e.g., FSC Recycled, SFI Certified Sourcing). Higher recycled content reduces virgin-fiber upstream emissions.
3. Mill energy data: Biomass self-generation fraction, renewable electricity procurement, and fossil fuel usage for lime kiln and recovery boiler.
4. FSC or PEFC chain-of-custody certification: Verifies sustainable forestry practices for virgin fiber input.
5. Lightweight board data: Reduced basis weight (thinner liners, optimized flute profiles) directly reduces per-unit emissions.

Methodology Notes

• CCI score of 1.3 kgCO2e/kg represents a conservative estimate for US-produced corrugated board with ~40% recycled content. FEFCO data for European production (higher recycled content) reports 0.7-1.0 kgCO2e/kg. AF&PA data for US production reports 1.0-1.4 kgCO2e/kg.
• Scope breakdown: Scope 3 dominates at 62% (0.8 kgCO2e/kg), driven by virgin fiber supply chain, recovered fiber collection/sorting, and chemical inputs. Scope 1 is 23% (0.3 kgCO2e/kg) from on-site combustion in recovery boilers and lime kilns. Scope 2 is 15% (0.2 kgCO2e/kg) from grid electricity for paper machines and corrugators.
• Confidence: High because corrugated board has extensive published LCA data, multiple EPDs, and well-established industry benchmarks.
• Functional unit: 1 kg of single-wall C-flute corrugated cardboard, cradle to gate.
• Biogenic carbon: Following industry convention, biogenic CO2 from wood fiber is reported separately and excluded from the GWP score. Wood-based carbon in the product is approximately 0.4 kgC/kg (1.5 kgCO2e/kg of biogenic carbon storage).
• End-of-life: Corrugated cardboard has the highest recycling rate of any packaging material (~80% in the USA, ~85% in the EU). End-of-life credits are excluded from the cradle-to-gate score.