For our customer, Virtuabroker, a cryptocurrency trading platform, we have created a Carbon Dioxide emissions calculator for cryptocurrency transactions. An article by Gallersdörfer, Klaassen and Stoll was the seed of my thinking. In simple terms, the method outlined in this paper allowed us to find values for the Power of the entire networks of each Proof-of-Work cryptocurrency. Then, using values for the number of daily transactions, we could find the Energy consumptions due to each individual on-chain transaction. Using a map of miners around the world from the Cambridge Bitcoin Electricity Consumption Index, we could come up with a rough estimate for Carbon intensity of mining and therefore, we could find values for the mass of CO2 emitted per on-chain Proof-of-Work transaction. For the Proof-of-Stake coins, we obtained rough estimates by following a method similar to an article written by Tezos.
Many thanks to Gallersdörfer, Klaassen and Stoll, those at the Cambridge Bitcoin Electricity Consumption Index and those at Tezos. If you have any questions about the methods used or the assumptions made, please do not hesitate to get in touch. This is still a work in progress so any recommendations or enquiries would be much appreciated as they could help towards future development.