How the Climate Cost Index (CCI) is calculated

What the CCI Measures

The Climate Cost Index (CCI) is a standardised, single-number score expressing the greenhouse gas emissions attributable to manufacturing one unit of a product, expressed in kgCO₂e per unit. It covers the cradle-to-gate lifecycle boundary: from raw material extraction through factory gate, including all upstream supply chain emissions but excluding use-phase and end-of-life. The score is always presented as a conservative upper-bound estimate — it reflects what a product’s footprint plausibly is in the absence of verified supplier-specific data.

A second indicator — kgCO₂e per kg of product — normalises the score by the product’s mass, allowing comparison across product categories with different typical weights. A smartphone scoring 75 kgCO₂e per unit and weighing 200 g has a score of approximately 375 kgCO₂e/kg. This normalised figure helps identify which product categories are intrinsically carbon-intensive relative to their physical mass.

The CCI is not a lifecycle assessment in the full academic sense. It does not attempt to model every emission from every process for a specific product. Instead, it is a structured benchmarking framework that assembles the best available data for a product category into a defensible, reproducible estimate. The target audience is buyers, procurement teams, and the general public — people who need to compare products across categories without commissioning bespoke LCAs.

The Data Hierarchy

The CCI applies a strict evidence hierarchy to determine which data source to use for each element of a product’s footprint. Higher-ranked sources override lower-ranked ones:

Level 1 — Verified product-specific LCA. A peer-reviewed, third-party verified lifecycle assessment covering the specific product category, with system boundary aligned to cradle-to-gate. This is the gold standard. Examples: published peer-reviewed journal articles with full LCA data tables; ISO 14044-compliant LCA studies reviewed by an independent critical review panel.

Level 2 — Manufacturer environmental report. A product-level carbon footprint published by the manufacturer and certified by an accredited third party against ISO 14067, PAS 2050, or equivalent. Examples: Apple iPhone Product Environmental Reports (certified per ISO 14067); Samsung Galaxy Carbon Trust certifications. These are product-specific and manufacturer-reported, making them higher quality than industry averages but potentially subject to commercial incentives in boundary choices.

Level 3 — EPD or industry association data. An Environmental Product Declaration registered with a recognised programme operator, or a dataset published by a credible industry association (e.g., the World Steel Association’s average emission factors for crude steel production, or the Aluminum Association’s material intensity data). These are category-average figures rather than product-specific ones.

Level 4 — Academic literature and government datasets. Peer-reviewed lifecycle inventory studies from academic journals; government-published emission factor databases (US EPA, UK BEIS, European Environment Agency). These are used where manufacturer or association data is not available.

Level 5 — Proxy estimation. Where no direct data exists, the CCI constructs a proxy estimate from material composition (mass of each input material × emission factor per unit mass) plus energy consumption estimates from comparable process data. This is the least certain methodology and results in a “low” confidence rating.

In practice, most product categories use a combination of levels. A smartphone score might combine Level 2 manufacturer data for the final assembly stage, Level 1 academic LCA data for semiconductor fabrication, and Level 3 industry data for the battery cell.

Scope 1, Scope 2, and Scope 3 Breakdown

Every CCI score is disaggregated into three scope components, following the GHG Protocol framework:

Scope 1 (direct process emissions at the point of manufacture): Combustion of fossil fuels for process heat, solvent emissions, refrigerant leaks, and other on-site releases. For most consumer goods manufactured in modern facilities, Scope 1 is a small fraction of total footprint — typically 1–3%. It is calculated from process-specific emission factors where available, or estimated as a fixed percentage of total based on sector benchmarks.

Scope 2 (purchased electricity): Calculated as factory electricity consumption (kWh per unit) multiplied by the grid carbon intensity of the manufacturing region (gCO₂e/kWh). The CCI uses location-based Scope 2 factors from the IEA Emissions Factors dataset, defaulting to the most carbon-intensive plausible manufacturing region for each product category. For electronics assembled in China, the default is 565 gCO₂e/kWh (IEA 2024). Manufacturers who submit documented renewable energy procurement may qualify for a market-based Scope 2 adjustment in a provenance override.

Scope 3 (upstream supply chain): The dominant component for most product categories, typically 70–90% of total footprint. The CCI traces Scope 3 emissions through the major supply chain tiers: the emission factors for each input material (steel, plastic, glass, semiconductors, cotton, etc.) are sourced from lifecycle databases and multiplied by the quantity of each material in the product’s bill of materials. For products with complex, multi-tier supply chains — electronics, vehicles, textiles — the upstream Scope 3 computation is the most methodologically challenging part of the score.

Hotspot Identification

Each CCI wiki page includes a hotspot breakdown — a ranked list of the supply chain elements that contribute most to the total score. Hotspot analysis serves two purposes: it helps buyers understand where the emissions are concentrated, and it guides manufacturer engineering effort toward the highest-impact interventions.

For a smartphone at 75 kgCO₂e, the hotspots are:

• Integrated circuits and semiconductor fabrication: 35% of total (Scope 3)
• PCB and passive component assembly: 15% of total (Scope 3)
• Display assembly and glass production: 18% of total (Scope 3)
• Battery (lithium-ion cell manufacturing): 14% of total (Scope 3)
• Final assembly, packaging, and logistics: 18% of total (Scope 2)

Hotspot percentages are rounded and may not sum precisely to 100% due to minor scope overlaps. They represent the CCI’s best estimate of the proportional contribution of each supply chain element, based on the data sources used to construct the score.

Confidence Ratings

Every CCI score carries a confidence rating of high, medium, or low:

High: At least one verified manufacturer report (Level 2) or peer-reviewed LCA study (Level 1) is available and anchors the estimate. The score is unlikely to differ from the true value by more than ±15%.

Medium: The score is based primarily on industry average data (Level 3) and academic literature (Level 4), without a manufacturer-specific verified figure. Uncertainty range is approximately ±20–30%.

Low: The score relies substantially on proxy estimation (Level 5). Uncertainty may exceed ±40%. These scores are published to provide at least a directional indication where no better data exists, but buyers should treat them with appropriate caution.

The confidence rating also reflects data vintage: a score built from LCA studies more than seven years old may be downgraded one level even if the original data quality was high, to account for changes in manufacturing processes and grid intensity.

Provenance Overrides

The CCI default score is the best estimate for a product category in the absence of supplier-specific data. Manufacturers and suppliers can submit verified primary data to replace the default with a product-specific score — called a provenance override.

Acceptable override documents include:

1. A third-party certified Product Carbon Footprint per ISO 14067 or PAS 2050, covering at least the A1–A3 lifecycle modules
2. A registered EPD from a recognised programme operator
3. A bill of materials with supplier-specific emission factors for key components, combined with factory energy data certified by an accredited auditor
4. Documented renewable energy certificates (RECs) or power purchase agreements (PPAs) for assembly facilities, which may reduce the Scope 2 component

When a valid override is accepted, the product wiki page is updated to show the override score alongside the default, with the data source and certification body identified. The override score may be lower or — in cases where the default was optimistic — higher than the default.

Self-declared carbon claims without third-party certification are not accepted as provenance overrides. The CCI requires an independent verification step to prevent greenwashing in the override mechanism itself.

Version History and Updates

CCI scores carry a methodology version identifier (e.g., “1.0”). This allows users to track changes over time as new data becomes available, LCA databases are updated, or methodology refinements are made. Key version milestones:

• v1.0: Initial release. Scores based on best available data as of April 2026. Grid intensity values from IEA 2024. LCA data from ecoinvent 3.10, US LCI Database, and peer-reviewed literature published through 2025.
• v1.1: Display rounding changed from nearest to ceiling (round-up) to avoid undercounting. Tiered formatting applied. No underlying data changes.
• Future versions will update grid intensity factors annually with each new IEA Emissions Factors release, and will incorporate updated LCA database versions as they are published.

A score update does not automatically invalidate a previously accepted provenance override, but overrides more than five years old are subject to renewal review.

Where to Learn More

The CCI methodology is described in full at /methodology, including the complete list of emission factor sources, the allocation rules for multi-output processes, and the treatment of biogenic carbon in bio-based materials. The methodology page also covers future development priorities, including plans to extend coverage to use-phase emissions for categories where use-phase dominates (large appliances, vehicles) and to incorporate water use and biodiversity impact indicators alongside the core GWP score.

For product-specific details — including the precise hotspot breakdown, data sources, and any active provenance overrides — see the individual product pages in the wiki. Each page documents the data lineage behind the score, so buyers and analysts can evaluate the evidence base themselves rather than taking the number on faith.