A bigger but somewhat slower growing China of the future will contribute about as much to global demand as the smaller but faster growing China of before. This is arithmetic: An economy that is twice as big can grow by half as much and contribute the same to global demand. By the way, China today is more than twice as big as it was a decade ago. So, the good news is, even with slower growth, China will continue to be an engine of global output. Indeed, an even bigger engine than before.