The world economy is currently in a state of profound change, arising from  the effects of four factors which determine four major trends. These are: a  drastic shift of the center of activities towards developing countries,  such as China; an accelerated spread and influence of technologies; rapid  ageing of population; and the growth of interdependence arising from the  flows of goods, capital, people, and information. Longterm macroeconomic  forecasts to 2050 are presented. In the medium term outlook for the global  economy, a new phase of‘differentiated growth’ is expected and examined.  The format of development in specific countries will vary considerably  according to government policies.