My world is in the future (very far, ~2480), but due to an energy crisis, the global economy has failed and has resulted in a sort of "medievalization" of the current nations. Given that present time has large areas that have a common currency, would these regions maintain a common currency, or would new currencies develop for each region?
Currency has always evolved throughout history.
The currency today LOOKS like the currency of the early 1800's, but it has become a 'spreadsheet' currency (most currency today is virtual, it is not in real, physical printed money). It has become debt-based, instead of cash-only. It has become a means of making more money in its own right (interest, for example, on money in bank accounts). It's value is now determined by it's relation to other currencies. Money is exchanged for another currency for profit. It's value is now determined by factors other than it's own physical existence. International banking is now more important to many economies than international trade.
I would suggest that history (the economic collapse of the 'dirty thirties') indicates that actual hard physical currency would once again dominate, over spreadsheet bank-balance currency. The economic model would change. The model would be based on 'present value' instead of 'future potential value'. It would be cash only, 'In God we trust, all others pay cash'. The plastic credit card economy would completely collapse. I can imagine everyone would go bankrupt, all loans and paper money (mortgages, stocks, bonds, bank accounts) would disappear. Huge sums of 'artificial' money would just vaporize. It would be a total reset back to a cash economy from a cashless economy.
But the actual cash, the physical currency, would still continue. People would still trade hard cash for goods, and then exchange that hard cash for other goods. The currency would still have 'value', but it would be real value, not virtual value.
It would be a return to the concept of currency in medieval times - the rich don't have bank accounts, or investments, or stocks, or bonds, they have a roomful of physical currency. 'Investments' would be in tangible products - land ownership, boats, means of production, animals - not money. But exchange would still be done in some form of common 'cash only' currency.
And this physical currency would be much the same as it is today.
The effects on society, and the impact of the economic collapse, would depend on how far the world had evolved into a 'cashless' currency model. The poor, and the marginally employed 'subsistence level' citizen, would see little change. They are pretty much already 'cash only'. But the middle class, whose wealth is now primarily 'cashless' wealth, would see significant impact.
Their wealth would reduce to whatever they had in their wallet.
As to whether there would be multiple currencies or a single surviving currency, it would depend on the extent of global, vs local, trade and travel. If trade was global, it would be done in some globally-based currency. However, if trade reverted back to local economies, then I suggest local currencies would become dominant. In medieval times, it did not make sense to use British currency in Germany, as there were very few opportunities to USE currency earned in Germany and spent in Britain.
Look at historical examples: When the romans ruled the world there was both roman currency and local currency floating around. Since it was metal based, when you ran into something new you weighed it.
Money is much like religion. People accept money because they believe that when they want something that someone else will in turn accept it. I work in your fields bringing in the hay. You give me a thingy. I take that thingy to the tavern and exchange it for a pail of beer (haying is brutally hot work) and some smaller thingies in change.
In another sense money is crystallized sweat.
In our present society most money is abstracted to bits in computer memory. Currency transactions are a small part of the exchange.
Ragnarok. All the bit type money (bitcoins especially...) evaporate. But the existing currency still has many of the attributes you want:
- Easy to carry
- Difficult to forge.
The problem would be the limited supply, and that paper money has a much shorter life span than coinage. It's not unreasonable for coinage to last for half a century of daily use. Paper money lasts 5-20 years currently, with the larger bills lasting longer.
A local warlord could establish the old coinage as currency by accepting taxes in it, and by being willing to exchange grain for it.
With time, as coinage grows more scarce it's value increases. The local warlord would coin new coins that were sub-multiples of the existing ones. These would vary from region to region with the region size being determined by the effective trading circle once the first warlord started making coin.
Making coinage would depend on what is left from the previous tech. It should be reasonable to make coins out of copper and brass. Sheet aluminum would stick around, and would be fairly easy to stamp. If there was any kind of remnant of electricity, you could do things like plate metals with copper or brass or zinc.
More info on making coins: http://www.classicalcoins.com/page103.html
This is a very broad question, probably the reason for the three close votes so far. I think I can give you an useful answer, however.
A kind-of-medieval view of currency is a lump of valuable metal stamped for weight and purity and hence useful for commerce. Take a gold coin and a gold nugget of the same weight and purity and they should have the same value, except for a small premium on the coin to account for the standardized weight.
A kind-of-modern view of currency is a promise of payment of value by the issuing authority (generally a nation or group of nations these days). During the transition period, paper money could be tied directly to gold or silver. "Pay the bearer of this note one pound sterling silver."
As economies evolve they leave the gold standard, not least because it ties the money supply to the gold supply. Careless governments may get into high inflation when they abuse the system, careful governments will keep the inflation just high enough to keep the economy ticking (the opposite of inflation is deflation, which is bad for the economy).
So what standard are those re-medievalized nations of yours using? It could be that they are using currency as a stamped lump of metal, and still (for traditional reasons) use the old names. So there could be gold dollars in America, gold pounds in England, and gold euros in continental Europe. Merchants and kings might even insist on standard weights, so a gold dollar from the Prince of Philadelphia and a gold dollar from the Duke of Dallas are both 20 gram, say, only the Earl of Edmonton strikes 18-gram gold dollars and merchants know to be wary.
Follow-up: Deflation is bad for the economy when keeping the money under the mattress has a higher return on investment than spending the money on the inventory of a shop or a similar economic activity.
It is not very clear as to what "medievalization" means, and I will assume it is a "halfway apocalypse".
Here are my assumptions:
- Global trade and travel will collapse to a small fraction of today's value;
- National energy grids and infrastructure networks will cease to exist;
- Central governments of large countries will either disappear completely or continue to function in a nominal way;
- Technology will plummet to XIX-century level, however, there still be quite a few old relics around, like computers and tanks, carefully maintained and used;
Given the conditions above, it is reasonable to expect that global currencies of today will disappear or their role would be greatly diminished. Two factors would contribute to it:
- Currency is national. If USA gets fractured to a number of smaller states, there will be no support for the old green buck, and its value would disappeared. New states would have every interest in minting and supporting their own coin.
- Modern currency is a fiat currency. Fiat money have no intrinsic value, commonly it's just a piece of paper. Fiat money's value is typically supported by issuing authority. In the times of crisis, fiat money is known to undergo rapid inflation, and people are know to flock away from it.
Also, curiously enough, I believe that cryptocurrencies like Bitcoin would not only be used, but would be even more trusted than small-states money. If there is still a number of running computers, and they are connected to the network (you don't really need a full scale national grid for that), Bitcoin transactions would go flawlessly like today, and will be more reliable than any other medieval-style operations. Bitcoin also would be impervious to governments' collapses and inflation.