Since 2008, total public and private debt in major economies has increased by over $60tn to more than $200tn, about 300 per cent of global gross domestic product ("GDP"), an increase of more than 20 percentage points.

Over the past eight years, total debt growth has slowed but remains well above the corresponding rate of economic growth. Higher public borrowing to support demand and the financial system has offset modest debt reductions by businesses and households.

If the average interest rate is 2 per cent, then a 300 per cent debt-to-GDP ratio means that the economy needs to grow at a nominal rate of 6 per cent to cover interest.

Financial markets are now haunted by high debt levels which constrain demand, as heavily indebted borrowers and nations are limited in their ability to increase spending. Debt service payments transfer income to investors with a lower marginal propensity to consume. Low interest rates are required to prevent defaults, lowering income of savers, forcing additional savings to meet future needs and affecting the solvency of pension funds and insurance companies.