In a world economy rapidly running out of bright spots, many are putting their hopes on the emerging and developing economies. Many experienced very rapid growth over the past decade, and most have recovered quickly from the 2008-2009 crisis.

Optimism abounds. Citigroup predicts real gross domestic product will grow more than 9 per cent a year in Nigeria and India, and more than 7 per cent in Bangladesh, Indonesia and Egypt over the next two decades. In a new Peterson Institute for International Economics study, Arvind Subramanian projects that aggregate output of developing and emerging economies will expand at an annual rate of 5.6 per cent over the same horizon.

If they prove correct, developing countries will make a substantial contribution to aggregate demand in the struggling rich countries and ensure the world economy’s steady growth. We shall witness the most impressive closing of the gap between rich and poor in history.