Offsets, often based on paying to plant trees or absorb carbon through restoring other ecosystems such as peatlands, face criticism due to the difficulty of quantifying the carbon absorbed and controversy around “double-counting”, where two businesses both claim the same carbon removal.
Dr Catherine Flick, a reader in computing and social responsibility at De Montfort University, said: “It’s kind of like a collectible card game. I think there’s a limit to the sustainability of that, as well.
“The initial push for it will be exciting and maybe make a lot of money, but I suspect this whole thing is going to die down quite significantly in a few years’ time, as people realise they are pretty worthless.
“Is that worth the hit for the climate that it’s making? Especially completely frivolous stuff like this.”
A spokesman for the museum said it would soon be moving to “Ethereum 2.0”, a new version that uses significantly less energy, though this project has been repeatedly delayed.
He said: “We are serious about our commitment to sustainability and the environment and have put in place a plan to minimise the impact.
“In technical terms, the British Museum’s NFTs are currently on the Ethereum blockchain and we plan to move to Ethereum 2.0 as soon as it is made available this year.
“Ethereum 2.0 only requires a tiny fraction of the energy usage compared to Ethereum.
“Our NFT partner LaCollection is also currently undertaking an analysis of the environmental impact of the programme and investigating the best possible offset solution – we expect any solution to offset existing energy usage and any future developments.”