Emission Impossible: privacy-preserving carbon emissions claims
Jessica Man, Sadiq Jaffer, Patrick Ferris, Martin Kleppmann, and Anil Madhavapeddy
1st International Workshop on Low Carbon Computing (LOCO),
Glasgow, UK,
December 2024.
Abstract
Information and Communication Technologies (ICT) have a significant climate impact, and data centres
account for a large proportion of the carbon emissions from ICT. To achieve sustainability goals, it
is important that all parties involved in ICT supply chains can track and share accurate carbon
emissions data with their customers, investors, and the authorities. However, businesses have strong
incentives to make their numbers look good, whilst less so to publish their accounting methods along
with all the input data, due to the risk of revealing sensitive information. It would be
uneconomical to use a trusted third party to verify the data for every report for each party in the
chain. As a result, carbon emissions reporting in supply chains currently relies on unverified data.
This paper proposes a methodology that applies cryptography and zero-knowledge proofs for carbon
emissions claims that can be subsequently verified without the knowledge of the private input data.
The proposed system is based on a zero-knowledge Succinct Non-interactive ARguments of Knowledge
(zk-SNARK) protocol, which enables verifiable emissions reporting mechanisms across a chain of
energy suppliers, cloud data centres, cloud services providers, and customers, without any company
needing to disclose commercially sensitive information. This allows customers of the cloud service
to accurately account for the emissions generated by their activities and identify opportunities to
reduce them.