AI Vocabulary · 08 Rules & Responsibility

What is Scope 2 Emissions?

The greenhouse gas emissions caused by the electricity a company buys, counted either by the local grid (location-based) or by its contracts (market-based).

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Climate accounting sorts emissions into three scopes. Scope 2 covers the emissions from purchased electricity, heat and cooling. For AI, this is the electricity of the data centres that train and run models. Scope 2 can be counted in two ways. The location-based method uses the average emissions of the grid where the electricity is consumed. The market-based method uses what the company has contracted, for example through power purchase agreements and certificates.

The gap can be large. For 2024, Google reports 345 g CO2 equivalent per kWh location-based and 94 g market-based. A Guardian analysis found the in-house data centre emissions of Apple, Google, Microsoft and Meta for 2020 to 2022 to be about 7.6 times higher location-based than officially reported. The GHG Protocol, which sets the global standard, is revising Scope 2 to require hourly and local matching for clean energy claims.

Why it matters for you

Your provider's emissions become part of your own footprint when you report on the AI you use. Knowing which method a figure uses tells you whether it shows the physical grid where the work runs or the contracts a company has signed.

Own it

Ask providers for both figures, location-based and market-based, and report both yourself. Note the method next to every number, and watch for the revised GHG Protocol rules, planned in full for the end of 2027.

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