Behind AI Data Centres Facing Emission Reporting Scrutiny

Data centre emissions reporting has come under scrutiny as AI workloads drive energy consumption higher, with new analysis suggesting major technology companies significantly understate their environmental impact.

The International Energy Agency estimates data centres and data transmission networks each account for 1-1.5% of global electricity use. 

However, Guardian analysis indicates actual emissions from facilities owned by Google, Microsoft, Meta and Apple were around 7.62 times higher than officially reported between 2020 and 2022.

The data centre emission reporting problem

Data centres worldwide consume approximately 460TWh of electricity annually and could reach 1,000TWh in coming years – equivalent to Japan’s total energy consumption. 

These facilities produce around 3% of global carbon emissions, matching the aviation industry’s contribution.

The discrepancy between reported and estimated actual emissions shows the challenges in measuring the environmental costs of digital infrastructure as AI adoption accelerates across industries.

Microsoft’s Senior Director of Sustainability, Dr Amy Luers, says: “This is a fast-moving space and these numbers come with uncertainty.”

“Anchoring discussions in trusted sources like the IEA helps cut through the noise and support more informed dialogue.”

However, she cautions against relying exclusively on single data sources: “But using estimates from the IEA and similar trusted organisations as benchmarks — especially when analysts and media use them to understand and explain why a figure is higher or lower — can help strengthen the dialogue.”

Amy advocates for transparency in emissions reporting methodology; “Let’s keep working to cite data, state assumptions and benchmark wherever possible,” she says.

Amazon Web Services leading cloud emissions

Thanks to varying reporting methods and data availability, identifying  a single largest emitter is not simple, but Amazon Web Services (AWS) — the world’s largest cloud provider — is typically seen as the most prominent data centre emissions emitter.

Microsoft, Google, Meta and Apple are still also significant emitters, though some have suggested their reported emissions often significantly underrepresent the actual levels.

Raw emissions data for AWS data centres specifically are not publicly set out by Amazon in its sustainability reports. 

However, the 2024 instalment says that while Amazon’s absolute carbon emissions rose from 64.38 million MTCO₂e in 2023 to 68.25MTCO₂e in 2024, the carbon intensity of its business declined, with emissions per dollar of gross merchandise sales falling from 75.6g CO₂e to 72.6g CO₂e, showing improved efficiency despite growth

AWS data centres are however known for their strong operational efficiency, with a global Power Usage Effectiveness (PUE) of 1.15 in 2024, outperforming the public cloud industry average PUE of 1.25.

All five tech companies have made carbon-neutrality pledges, mostly with 2030 as a date set to accomplish them by. 

Google, for instance, aims for 24/7 carbon-free energy for its data centres and offices by the end of the decade.

Simultaneously, Microsoft has committed to becoming carbon negative, removing all the carbon it has emitted since it was founded.

Google’s change of carbon strategy

Google has modified its carbon neutrality approach, ending mass purchases of carbon offsets and no longer claiming carbon neutral operations, a status it had maintained since 2007. 

The company now targets net-zero carbon emissions by 2030.

Google’s 2024 Environmental Report showed overall greenhouse gas emissions increased 13% year-over-year in 2023, with AI and data centre energy consumption contributing to this rise.

Google Chief Sustainability Officer Kate Brandt and Benedict Gomes, Senior Vice President for Learning & Sustainability, acknowledge the challenges in their environmental report: “In spite of the progress we are making, we face significant challenges that we’re actively working through,” they say.

“In 2023, our total GHG emissions increased 13% year-over-year, primarily driven by increased data centre energy consumption and supply chain emissions.”

The executives also emphasise the need for systemic change: “A sustainable future requires systems-level change, strong government policies and new technologies. 

“We’re committed to collaboration and playing our part, every step of the way.”

All five technology companies have established carbon neutrality commitments, with most targeting 2030 for completion. 

Google aims for 24/7 carbon-free energy for its data centres and offices by decade’s end, while Microsoft has committed to becoming carbon negative, removing all carbon emitted since the company’s founding.

Morgan Stanley projects AI-optimised data centres will quadruple their electricity consumption, with global emissions from these facilities rising from 200 million metric tons currently to 600 million tons annually by 2030.

Microsoft Vice Chair and President Brad Smith emphasises the importance of transparent reporting in the company’s sustainability report, saying: “We believe data transparency is critical to driving accountability and progress on climate.”