LONDON — You have to hand it to the economics team at Goldman Sachs. It was they who came up with the concept of the "BRICs": the four big economies, in Brazil, Russia, India and China, that were going to catch up with and then overtake the big economies of the developed world.

More recently they added the "Next 11": middle-size developing countries like Turkey, Indonesia and Mexico that will also grow fast enough to overtake their old-rich counterparts in the next generation.

Back in 2006, Goldman Sachs predicted that the Chinese economy would surpass that of the United States in the early 2040s, with the Indian economy not far behind. But now the Goldman Sachs team has put out a new set of forecasts. The Chinese economy, they predict, will overtake the U.S. economy around 2025, and will be twice as big by 2050.