Readers’ comments

Central cryptoheating

The negative consensus assessment of cryptocurrencies in last month’s issue (see issue 324, p26) isn’t strong enough in my opinion. They are nearly useless as currencies because they do not have sufficient transaction capacity and the value is too volatile. As assets, they are a pure Ponzi scheme. Unlike gold, the energy consumption used to limit the supply of cryptocoin is not recoverable. By contrast, the so-called “fiat currencies” are backed by the tax-raising powers of the governments that issue them.

The farmer who uses biomethane to generate electricity for cryptomining isn’t being green. He is releasing just as much stored carbon into