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ChartHardwareOrganisations · tCO2e
Published on 20 October 2026

Training emissions, 4 published assessments

Training emissions, in tCO2e (logarithmic scale)

Training emissions, 4 published assessments

1001,000× 1010,000× 10100,000× 10ScalelogarithmictCO2e (logarithmic scale)OLMo, trial runsdevelopment, 2025159 tOLMo, trainingfinal training, 2025312 tGPT-3estimate, 2020552 tLlama 3.13 sizes, 202411,390 t
Source: Morrison et al., 2025; Patterson et al., 2021; Meta, 2024. projetcelsius.com/en/ai · CC BY 4.0AI Impact, by Projet Celsius

The analysis

  • The trials before the final model weigh half of the final training at OLMo: a cost that other providers do not publish.
  • Llama 3.1 emits 20 times GPT-3: the models are larger and trained for longer.
  • Training is only one part: for Mistral Large 2, training and 18 months of use add up to 20,400 tCO2e.

The figures

  • OLMo, trial runs (development, 2025): 159 t.
  • OLMo, training (final training, 2025): 312 t.
  • GPT-3 (estimate, 2020): 552 t.
  • Llama 3.1 (3 sizes, 2024): 11,390 t.

Assumptions

  • Training electricity, unless stated otherwise; hardware manufacturing not counted.
  • Large closed models (GPT-4 and later, Gemini, Claude) do not publish their training assessment.
  • Different methods and electricity grids from one assessment to another.

Published on 20 October 2026MethodologyAll sourcesLicence CC BY 4.0

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