Global central banks are afraid. Before Greece tried to stand up to the Troika, they were merely worried. Now it's clear that no matter what they tell themselves and the world about the necessity or even righteousness of their monetary policies, liquidity can still disappear in an instant. Or at least, that's what they should be thinking.

The Federal Reserve and US government led policy of injecting liquidity into the US and then into the worldwide financial system has resulted in the issuance of trillions of dollars of debt, recycling it through the largest private banks, and driving rates to 0% — or below. The combined book of debt that the Fed and European Central Bank (ECB) hold is $7 trillion. None of that has gone remotely into fixing the real global economy.