Emission Impossible: privacy-preserving carbon emissions claims

It all started in September 2024, when Prof Anil Madhavapeddy suggested a paper for me to work on and told me to “have fun with it”. The paper was originally authored by Dr Sadiq Jaffer, Patrick Ferris and Anil himself, it was such a great opportunity to work with them and it’s an interesting paper to work on. I have always wanted to work with cryptography, it’s such a good sustainability-related topic too! I was secretly excited about it, a bit like a child who was given a new puzzle solving toy.

At the same time, Dr Martin Kleppmann started his full-time role in the department. Incidentally, he has also been working on applied cryptography for sustainability. A few conversations later, he became my primary supervisor and I have been working in this research direction ever since.

The extended abstract version of the paper was submitted and accepted at the 1st International Workshop on Low Carbon Computing (LOCO 2024) workshop, and in April this year, the full paper was also accepted. The camera-ready version is now available on arXiv.

Here is the 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 cloud services to accurately account for the emissions generated by their activities, improving data quality for their own regulatory reporting. Cloud services providers would also be held accountable for producing accurate carbon emissions data.

I want to thank all the co-authors on this paper, I have certainly enjoyed working on it!