> Most of the increase could be fully offset if the world put an end to the incredible waste of electricity on cryptocurrency mining (currently 0.5 to 1 per cent of total world electricity consumption, and not normally counted in estimates of IT use).

I do not accept this. It was once true under Proof-of-Work (typically ~1,000–2,000 kWh per transaction), not so much under Proof-of-Stake (typically 0.03–0.05 kWh per transaction).

Note that proof-of-stake may actually have a lower energy footprint than credit card or fiat banking transactions. An IMF analysis [1] pegged core processing for credit card companies at ~0.04 kWh per transaction (based on data centers and settlement systems), but noted that including user payment means like physical cards and terminals could increase this by about two orders of magnitude—though even then, it doesn't extend to bank branches or employee overhead - an overhead not implicit in decentralized finance.

[1] https://www.elibrary.imf.org/view/journals/063/2022/006/arti...