This new global currency (call it *G)  would be used to settle all international transactions.  It would be a new digital currency that has a recursive value, such as the US Dollar did after Brentwood.  The *G's  value will not vary over time, because it exists in a political and marco-economic vacuum.

A global currency does not have any value as accrued capital, it is simply a reference currency for  international transactions that will be settled at some future time, at the then prevailing national currency exchange rates.  This new currency would exist only in a cyberspace, it's value is a human quantum, not a financial one.  

We must be able to communicate real value in our interconnected world. If a barrel oil could be traded on the various commodities exchanges for x number of *G's, it's value would not depend on the exchange rate of the various national currencies against the *G, only on the supply and demand of oil that day.   Stocks and bonds could be traded in *G's,and paid in *G's at maturity or redemption, at the exchange rate of that time and place.   This level of financial abstraction is relatively simple to achieve in our cybernetic banking systems, it actually simplifies what is now a chaotic multi-currency kludge.

Since no single country or region would "own" this global currency, it would not be subject to the normal variances that occur in national economies. In due time, all transactions that can use it as a base of reference would do so, even at the retail level, since it would provide an global physiological value reference to international consumers, much as the US Dollar did until 2008.  

There is no limit to the amount of *G's that can be made available, since this is a currency that is not accrued in accounts, it exists only as a reference for actual international transactions.  By definition, a *G is a semantic concept that is monetized only when there is a transaction between two or more parties to a contract, be it public or private. 

All transactions would require counter-transactions,any debit in G's will require a counter credit for the same amount.  The  financial advantage being that the *G's can be booked by all parties as assets or liabilities into the future, without regard to currency exchange at the time and place where the transaction is liquidated. This means that all nations would potentially be at the same level of wealth, given that the *G is instantiated at the construction of a financial object, it is not  a precursor to it.

Unlimited global funds would be available for any project that has merit, either due to it's financial return or because of it solves a social or ecological need.  Since *G's are in essence information, there is no inherent limit to creating them, since they are destroyed at liquidation time and do not devalue. What we have today is a scarcity of ideas for viable projects, not a scarcity of money.