The Organisation for Economic Cooperation and Development has predicted a dramatic shift in the balance of economic power in the next half century.
In a report, the OECD says emerging economies will account for an ever increasing share of output, and China will overtake the United States as early as 2016, the BBC reports.
The organisation expects the current trends of faster growth in emerging economies to continue.
The result is that the largest of them, those with the biggest populations, will overtake what the OECD calls fast-ageing economic heavyweights, such as Japan and the eurozone.
On the basis known as purchasing power parity, which tends to favour emerging countries, China and India combined will be larger than the entire developed world by 2060.
The report says gaps in living standards will narrow, but will not be eliminated.
In the poorest countries, income per person is predicted to quadruple. For China and India, it will increase sevenfold.