Additionally, the "environmental disaster" claims have always seemed shallow to me. Yes, it is a serious issue if everyone is mining with coal powered electricity, but how did it get so cheap? Isn't it on the government to not subsidize coal? The largest mining companies are finding super cheap energy in renewables (1). In the long run, I feel like mining is what can pay for further investment in renewables. For instance, see the article below about Germany paying customers to use electricity (2). Seems like government level mining might be a good investment.
1. https://globalnews.ca/news/3974083/bitcoin-mining-quebec-can...
2. https://www.independent.co.uk/environment/germany-grids-payi...
Distributed blockchains.
I'm not saying blockchains are bad technology, non-distributed blockchains can be a very good solution to certain problems, but it's not the "world changing" revolution many claim it to be.
If you're local (or within a small network with bounded, you don't really need asynchronous consensus. Dolev-Strong or any number of other synchronous/semi-synchronous protocols would work fine.
> non-distributed blockchains can be a very good solution to certain problems
How I see it: blockchaining is an arms race in computing power. In order to sufficiently 'secure' your chain you need to spend more value (electricity) than an attacker is willing (or capable) of spending. This makes blockchains very expensive, slow and an environmental disaster.
Unless a blockchain has tremendous value (like cryptocurrencies currenly have) there is no way to sustain them.