Climate Cost Index (CCI) — Methodology

1. Purpose & Scope

The Climate Cost Index (CCI) is an open, versioned methodology for estimating the embodied carbon footprint of consumer product categories. It is designed to serve three audiences:

• The public: A free, accessible reference for understanding the carbon embedded in everyday goods
• Sustainability professionals: A consistent, sourceable baseline for supply chain carbon accounting
• Suppliers: A transparent framework against which verified product-level data can be submitted and scored

The CCI covers embodied carbon only — that is, greenhouse gas emissions associated with the extraction, processing, manufacturing, and transport of physical goods. It does not cover use-phase energy consumption or end-of-life emissions, except where noted in individual category pages.

All emissions are expressed in kilograms of CO₂ equivalent (kgCO₂e) using IPCC AR6 100-year global warming potential (GWP100) values.

2. Foundational Principles

2.1 Conservative-First Scoring

The CCI defaults to worst-case plausible assumptions for every category. This means:

• Highest-emission material compositions are assumed where composition is variable
• Highest-emission manufacturing geographies are used as defaults
• No credit is given for recycled content unless verified
• No credit is given for renewable energy unless verified

This approach is deliberately anti-greenwashing. The burden of proof is on suppliers to demonstrate lower emissions — not on the wiki to assume them. A product's score can only improve through verified data submitted via the Provenance Override process (see Section 7).

2.2 Full Lifecycle Coverage (Cradle-to-Gate)

The CCI covers emissions from raw material extraction through point of manufacture (cradle-to-gate). This aligns with ISO 14067 and PAS 2050 scope for embodied carbon. For categories where transport to end consumer represents a significant emissions source (e.g., imported goods), a transport module is added and disclosed separately.

2.3 Scope 1 / Scope 2 / Scope 3 Decomposition

Every CCI score is broken into three components aligned with the GHG Protocol:

• Scope 1: Direct emissions from manufacturing processes (combustion, chemical reactions, on-site fleet)
• Scope 2: Indirect emissions from purchased electricity and heat consumed during production
• Scope 3: All upstream value chain emissions — raw material extraction, processing, transportation of inputs, supplier operations

For most consumer goods, Scope 3 (upstream) represents 70–90% of total embodied carbon. The CCI makes this visible rather than obscuring it in aggregate figures.

2.4 Transparency by Default

Every score on Climate Cost includes:

• The emission factor sources used
• The assumptions made
• The methodology version applied
• The date of last review

No score is published without a source trail. Where data quality is low, this is flagged explicitly with a confidence rating (see Section 6).

3. Emission Factor Sources

The CCI draws from the following primary data sources, in order of preference:

Where multiple sources are available for a category, the CCI uses a weighted average or selects the most conservative estimate, documented explicitly on the category page.

4. Category Score Calculation

4.1 The CCI Formula

Each category receives a default CCI score expressed as:

Where S1, S2, and S3 represent scope-specific emission contributions estimated from the methodology above.

For categories where "per unit" is ambiguous (apparel, raw materials, packaging), scores are also expressed as kgCO₂e per kilogram of product.

4.1.1 Worked Example — Smartphone

This walks through how the CCI score for the Smartphones category (75 kgCO₂e per unit) is calculated:

4.2 Material Composition Assumptions

For each category, a default bill of materials is defined based on the most common or most emissions-intensive composition found in the literature. Example:

• Smartphone: Default assumes aluminum casing, lithium-ion battery (cobalt-heavy chemistry), display glass, printed circuit board assembly, and packaging. No recycled content assumed.
• Cotton T-Shirt: Default assumes conventional (non-organic) cotton, grown in a water-intensive region, dyed with conventional processes, manufactured in a high-emission grid country.

Material composition assumptions are published in full on each category page.

4.3 Manufacturing Geography

Grid carbon intensity varies dramatically by country. The CCI uses IEA country-level carbon intensity factors to calculate Scope 2 emissions for each category's assumed manufacturing location.

Default manufacturing locations are set to the highest-emission plausible geography for that product category, unless peer-reviewed literature provides strong evidence for a different global average. These defaults are documented and versioned.

Examples:

4.4 Regional Variation Module

For users in different markets, the CCI includes a regional variation note on each category page. This adjusts Scope 2 assumptions for locally manufactured alternatives (e.g., EU-produced goods benefit from lower-carbon grid mixes).

Regional variation does not change the default CCI score — it is provided as context. The default always reflects worst-case plausible, not regional average.

5. Scope Breakdown & Hotspot Analysis

Each category page includes a hotspot analysis — the top 3–5 emission drivers within the total score, with their estimated percentage contribution. This is designed to help sustainability teams identify where intervention has the most impact.

Example (Smartphone):

Hotspot percentages are estimates derived from the literature and are reviewed with each methodology version update.

6. Data Quality & Confidence Ratings

Not all categories have equal data depth. The CCI assigns each category a confidence rating:

Low-confidence scores are still published — because a conservative estimate is more useful than silence — but are flagged prominently with a disclosure on the category page.

7. Provenance Override — Supplier Data Submission

The CCI is designed to be improved by verified real-world data. Suppliers, brands, and manufacturers can submit a Provenance Override request to update their product's score if they can provide verified documentation.

7.1 Accepted Evidence Types

7.2 Process

1. Supplier submits documentation via the enterprise app (Tier 2)
2. Climate Cost reviews documentation for standard compliance
3. If validated: product receives a Verified CCI Score displayed alongside the default
4. Source documentation is linked publicly
5. Independent expert reviews borderline submissions

Provenance Override does not remove the default CCI score from the wiki. Both scores are shown, labeled clearly.

8. Methodology Versioning

The CCI methodology is versioned using a MAJOR.MINOR system:

• MAJOR version changes: Material changes to scope, formula, or source hierarchy
• MINOR version changes: Source updates, new regional data, hotspot refinements

All historical versions are archived. Every category page displays the methodology version under which its score was calculated. When the methodology updates, category scores are flagged for review.

Current version: 1.1

8.1 Version History

9. What the CCI Does Not Cover

To be explicit about scope limitations:

• Use-phase emissions (energy consumed while using a product) — not included in default CCI scores
• End-of-life emissions (landfill, incineration, recycling) — not included by default; noted where significant
• Carbon offsets — not factored into any score; offsets do not reduce embodied carbon
• Logistics / last-mile delivery — not included in default; available as an add-on module for enterprise users
• Biogenic carbon — treated as zero at point of use per PAS 2050 default; disclosed where relevant

10. Governance & Review

The full methodology, including version history, is published at climatecost.org/methodology and in the public GitHub repository.

11. Citation

To cite the Climate Cost Index methodology:

Climate Cost. (2026). Climate Cost Index (CCI) Methodology, Version 1.1. climatecost.org/methodology