China to overcome USA "before 2030" - much earlier I'd say

A study by the US official think tank National Intelligence Council admits that China will overcome the USA as first global power by GDP "before 2030". Of course... but why to say 2030 when it is likely that it will be by 2021 (by nominal GDP) or even much earlier (by GDP-PPP)?

In 2010 I reported that China would overcome the USA by GDP-PPP in 2018 (however present day IMF estimates already suggest 2017 in fact). As an exercise I have estimated at home that (at current growth rates) China will overcome the USA by GDP (nominal) in 2021:

Y-axis: nominal GDP in billion USD

By 2030 actually the US-China relationship will be totally inverted in relation to present day one in terms of absolute GDP (assuming that the forecast stands the test of time).

The NIC study is not realistic at all but rather self-complacent in fact. See for example how they dream to be at the same level as China in 2030:

click to expand

The overcome in GDP by China resembles a lot the same scenario in the late 19th century, when Germany overcame Britain in similar economic output figures (overall economic might) and, like China today, lacked of a colonial or semi-colonial network (and like China today worked frantically to attract low development powers like Russia and the Ottoman Empire to its orbit as result). 

The parallels may end there anyhow because while the British Empire had a creole backup replacement in the form of the USA, this one has no backup whatsoever. Also while Britain could push for all out war, today such eventuality is only the madman's option, as the whole planet would be razed to the ground.

Also Germany, Britain, the USA and most of the other actors in the early 20th century were of European culture (the main exception being Japan), today China stands to vindicate a long history of Asian global primacy which was only temporarily eclipsed by European mariner and mercantile audacity, this is a major unprecedented change in the overall human ethno-cultural landscape, at least for the last many centuries.

And such a rather unprecedented change is happening right now, almost...