"Earth is a poor store of life because it requires a constant stream of light to maintain." Hm no, that doesn't work...
Why was Bitcoin invented; what problem does it solve?
Cryptocurrencies are designed to waste increasing amounts of energy that grow both with time and the popularity of the system. Right now we're not able to pull energy from Sun fast enough to power them (see all the global energy issues, fossil fuels, etc.). And even if we eventually could, cryptocurrencies would only grow to consume all available energy. And even if we could keep up with that, it's an incredibly unnecessary waste if you compare all the other uses that energy could be put to. The guarantees that cryptocurrencies give are not worth the upkeep.
And that's all without discussing the other side of the coin - waste heat.
Actually there are thousands of other things that take way more energy and pollute way more than cryptocurrency mining. In fact you can locate your miners anywhere, unlike, say, your shipping vessels. So there's an incentive to place the miners next to, say, hydrothermal plants.
Why aren't you fervently arguing for the other orders-of-magnitude-larger polluters to be replaced? Lord knows we have alternatives to them too.
By the way, do you know about Bitcoin's emission curve and what is going to happen to mining after bitcoins are no longer emitted?
> And even if we eventually could, cryptocurrencies would only grow to consume all available energy.
That's a lot of energy! Could you provide some kind of grounds for your opinion here?
Because here I'm arguing against the trend, not just absolute magnitude. Almost every other human endeavour has incentives to reduce waste and upkeep. Cryptocurrencies require ever increasing energy use for maintaining the system.
(Note that I also frequently argue against various zero-sum games in the economy, like advertising, which are yet another unnecessary waste of precious resources. I try to be consistent with that position.)
> what is going to happen to mining after bitcoins are no longer emitted?
Isn't it true that Bitcoin requires continuous energy expenditure through mining to maintain the integrity of the network?
> That's a lot of energy! Could you provide some kind of grounds for your opinion here?
I'm talking about the dream/goal scenario of cryptocurrency advocates, in which cryptocurrencies replace fiat and become the new basis for the entire global economy. And the grounds are that the system is designed in a way that you literally make money burning electricity, so as long as electricity is cheaper than payoff somewhere (or you can steal some), there's strong incentive for everyone to try and burn energy.
Which increases energy costs until that profit gets small.
As long as there is a more valuable use for energy than getting a 0.1% profit mining Bitcoin, I don't see why mining would ever consume all energy, that's ridiculous.
I still don't understand why significant deflation is a desirable characteristic for a currency. Mild deflation is tolerable unless the economy is experiencing hyper-growth like the early 20th century, but Bitcoin is more deflationary than gold. Strong economic arguments that I don't have time to type in can be made that an ideal currency (as a medium of exchange) is slightly inflationary (in the monetary base sense) to the degree that the economy as a whole is growing.
Edit: collapse you say? But its value has held up! But this is exactly what happens (for a while) in a deflationary collapse. The value of money skyrockets but its velocity tanks.
http://charts.woobull.com/bitcoin-velocity/
Of course given all of Bitcoin's undesirable characteristics as a store of value I suspect that its value in USD/EUR/etc. will eventually tank as well. This might take a while unless something causes a panic since the market for BTC is slow and thinly traded.
IMHO all deflationary cryptocurrencies will undergo this kind of collapse.
Of course not all cryptocurrencies need be deflationary. Software defined money can be programmed to do anything you want it to do within the bounds of what is possible under e.g. the CAP theorem and other relevant concepts from distributed systems.
Cryptocurrency as a system is also inflationary in a whole-systems sense as new money can be created by forking a code base or creating a token on those coins (e.g. Ethereum) that support it. This argument holds as long as all these currencies are reasonably fungible without too much hassle. As it stands things like shapeshift.io make converting them fairly easy at least for the popular ones.