For a few years now, I and others been banging on about the environmental cost of Bitcoin, and similar cryptocurrencies. This cost from the electricity wasted on the pointless calculations used to ‘mine’ Bitcoins, under the ‘proof of work’ protocol used to ensure the validity of entries in the Bitcoin blockchain. The cost is huge, about the same as the energy use of a medium size country.

For almost as long, we’ve been promised an alternative ‘proof of stake’, in which the integrity of the blockchain would be protected by participants putting up some of their cryptocurrency as a ‘stake’ (more details here). But like nuclear fusion, proof of stale always seemed just over the horizon.

Now, it seems, it may be going to happen. Bitcoin’s biggest rival, Ethereum, has been testing a proof-of-stake blockchain for some time, in parallel with its existing proof-of-work chain. On 15 September, it is planned, the two will be merged in an event creatively called The Merge, and future operation will be proof-of-stake.

If this succeeds, the electricity consumption of Ethereum will be reduced by around 99 per cent. That will make it, in the words of Douglas Adams, mostly harmless. That doesn’t change the fact that, like cryptocurrencies in general, Ethereum is also pretty much useless. Its most notable function is as the basis for pricing non-fungible tokens (NFTs), digital certificates asserting ownership of an image (which anyone else can duplicate, but not own). That’s frivolous but no worse than collecting baseball cards or postage stamps (remember them?).

The big payoff from successful proof-of-stake is that it provides a way to kill the Bitcoin monster once and for all. Rather than banning Bitcoin, all that’s necessary is to ban proof-of-work. If Bitcoin made the transition to proof-of-stake, well and good. If not, no problem. Either way, its disastrous drain on world energy would be over.