There will be major changes in the composition of global GDP
Global GDP is taken as sum of GDP for 34 OECD and 8 non-OECD G20 countries.
Source: Long-term Growth Scenarios, OECD Economics Department Working Paper No. 1000
In late 1980s, the situations were very different (Japan: 8~9%, China: 3~4%, India: 2~3%, etc.)