What are some solutions to creating a "one world currency" ?

Question

What are some solutions to creating a "one world currency" ?

Answer 1

the whole world goes back to gold standard and not currency.

Its as simple as that

Answer 2

1) Come up to agreement between countries,

2) Develop proper and reliable model.

3) Set rules of this game

4) Appoint ruling board and main policy goals.

5) Remove transfer barriers between countries involved

6) Announce starting date and period of adaptation (transformation).

7) Start to accomplish program steps.