The carbon and water footprint of AI usage, as an open dataset

    An open, versioned set of emission and water factors for AI inference, with the method, the sources and the accounting guides behind it. Factor version soma-ai-ef-2026.10-dataset-v3.0.0. Last updated .

    What is the carbon footprint of AI usage?

    It depends on three things, and a single number hides all of them. The size class of the model, the cloud region it is served from, and what the estimate counts.

    A typical exchange of 1210 tokens with a mid-size model on the global-average grid emits about 0.053 g CO₂e. The same exchange costs 5.6 times as much from Asia Pacific - Singapore as from EU North - Sweden. A frontier model costs about 13 times a small one for the same tokens.

    SOMA publishes the factors that turn token counts from a provider invoice into a Scope 3 Category 1 line, with the uncertainty and the sources attached.

    They are estimates built from published benchmarks and published grid data, not readings of anyone's data centre. Every figure on these pages is derived from the dataset rather than typed in.

    Why use SOMA AI Emission Factors (SAEF)?

    • Open licence. CC BY 4.0, so a consultancy, an assurance provider or a software vendor can build on the factors and cite them.
    • Citable and versioned. Concept DOI 10.5281/zenodo.20443585 resolves to the latest version, and every older version stays resolvable, so last year's inventory can be reproduced. See the changelog.
    • Under peer review. The method is a preprint under review at Sustainable Production and Consumption.
    • Independent of the vendors it covers. SOMA does not sell AI models, so no row is a claim about its own product.
    • Built for the inventory. Four data tiers, one entry per service, mapped to GHG Protocol Scope 3 Category 1 and ESRS E1. Water is reported beside carbon and never added to it.

    Method and data

    • MethodologyHow a token becomes carbon and water: terms, tiers, classes, uncertainty and sources.
    • SOMA AI Emission Factors (SAEF)The full table across 18 regions and 3 model classes, with a CSV download and the dataset record.
    • AI factors APIOne factor row per request, for a model id and a cloud region.
    • ChangelogEach published version, its date, record and changes.

    Factors by model class

    • Class A: small modelsgpt-4o-mini, gpt-4.1-mini, gpt-4.1-nano. About 0.016 g CO₂e per 1210-token query on the global-average grid.
    • Class B: mid-size modelsgpt-4o, chatgpt-4o-latest, gpt-4.1. About 0.053 g CO₂e per 1210-token query on the global-average grid.
    • Class C: frontier modelsgpt-4, gpt-4-turbo, gpt-5. About 0.2 g CO₂e per 1210-token query on the global-average grid.

    Factors by cloud region

    One page per region, with the per-query figures, the split between electricity, hardware, construction and training, water, and the comparison with the other regions. Lowest carbon first for a mid-size model:

    Answers

    En español

    Guides

    Estimate your organisation's AI footprint

    The free AI footprint calculator applies these factors to the AI tools your teams use. Answer a few questions (tools, people, how often) and it estimates the CO₂e, electricity and water per team and per tool, with a range, and shows the changes that would cut it. Message counts from an admin export or token numbers from an invoice sharpen the estimate.

    Use the factors

    Download the table as CSV, cite the dataset by its concept DOI, or call the API. To have the usage exports of your AI providers turned into the finished inventory line, see SOMA AI Footprint.