Despite its positive aspects, the creation of a global currency also has negative aspects, related in particular to the local views of different countries.
1- Reducing the freedom of fiscal policy Domestic fiscal policies will be greatly affected with the emergence of a global currency. We must bear in mind the fact that the political and economic conditions in the countries of the world are different. Some of these countries are rich, others are poor. Some have democratic governments, while others are under the control of dictatorial regimes. And if the tour doesn't have complete control over its currency, it won't be able to address its economic concerns. For example, some countries may need to lower interest rates in the face of economic turmoil, which is impossible to do without having complete control over the currency used in the country. But with the use of a global currency, the freedom of fiscal policy will be curtailed.
2- One central bank and one policy. If a global currency is used, there will be one central bank in the world, which will be responsible for formulating the fiscal policy, which will be one that applies to all countries regardless of their circumstances, which will prevent some economic problems from being addressed. Including specific countries and not others. It is not possible, of course, to set different interest rates or different reserve levels for banks in all countries of the world.
3- The spread of economic problems in one country to all parts of the world When using a global currency, it will become easy for an economic problem in a particular country to affect all countries of the world. Perhaps the best example of this is what happened in the European Union, where the collapse of the Greek economy and the depression of Spain and Portugal spread throughout the European Union, with serious consequences even for established economic giants such as Germany and France.
4- Serving the interests of powerful countries only The global currency system will serve the interests of economically powerful countries only at the expense of smaller countries. It will likely have a better representation in the global central bank, and an upper hand in making fiscal policy. After touching on the pros and cons of using a global currency, we ask again, can there really be a single currency used all over the world? It is an idea worth aspiring to, but it is not viable under the current circumstances, as even in the European Union, there are still member states that are committed to using their own currency. Some are legally exempt, such as the United Kingdom and Denmark, while others, such as Poland, Sweden, Hungary, Romania, Croatia, Bulgaria and the Czech Republic, will start using the euro after certain conditions are met. However, it still has the right to keep its own currency. We can summarize the reasons that drive these countries to refrain from using the euro as follows:
1- Maintaining the independence of monetary policy, including the ability to put in place measures to control inflation and devalue the currency.
2- Freedom to make decisions regarding policies to meet the challenges specific to each country. 3- Having an independent lender of last resort which is the independent central bank of the country which has its own currency. These reasons apply to the rest of the world in the event that a single global currency is decided upon. It would be very difficult to persuade the world's governments to support this decision since the downsides and risks outweigh the positives, for the time being at least. Perhaps the only case in which the global currency will come close to the truth, will be after the emergence of a world war that wipes out the greater part of the universe, leaving a small group of survivors who wish to build a new great country under one economic system!