For 20 years the Centre for Economics and Business Research (Cebr) has supplied independent economic forecasting and analysis to hundreds of private firms and public organisations. They have annual forecasts of world GDP and GDP per capita.
In 2016, CEBR forecasts :
India is now starting to catch up with China and will eventually overtake in the second half of the century.
Korea is overtaking most of the European countries and will be one of the world’s top 5 economies at some point in the 2030s.
Nextbigfuture notes that a lot has to go right for India to achieve that kind of growth for that many decades.
This 2016 CEBR forecast is before China turned in better results for 2017.
Extrapolating from the pace of GDP growth from 2030-2031.
The top countries in 2040 would be
1. China $45 trillion
2. USA $39 trillion
3. India $16 trillion
4-7. South Korea, Germany, Japan, UK around $5-6 trillion
Extrapolating more recent IMF forecasts would suggest that China could surpass the US economy in 2027. Extrapolating China’s economy from the IMF numbers would suggest a China economy of about $50-55 trillion in 2040.
Sometime between 2025 and 2030 India should become the third largest economy.
If the IMF is correct about India’s economy in 2022 then the CEBR forecast for India in 2030 (twice as large as Japan) would be overoptimistic. India would more likely be at a GDP of $6-7 trillion in 2030.
The long range economic forecasts pretty much all have China as the number one world economy on a nominal GDP basis from 2030-2060. The uncertainty is how much larger the China economy will be than the US economy.
The long range forecasts pretty much all have India as the number three world economy sometime in the 2024-2030 timeframe. The uncertainty is how much larger the India economy will be than Japan (or Germany) in number 4 and how far India will lag the US or China’s economy.
There will be only a 20% differential between China and the US economy from 2023 through 2030. China lagging the US by 20% and the US eventually lagging China by 20%.
Nominal GDP is currency exchange dependent, so anything that radically adjusts currency valuations would cause a more rapid adjustment in nominal GDP rankings.