I question whether China has actually even surpassed Japan in GDP. As I've said before, I think China is a ticking time bomb that is in the midst of a massive bubble right now. Quite a few others believe this too, two prominent ones being Jim Chanos (who forsaw Enron's collapse) and economist Nouriel Roubini (http://www.project-syndicate.org/commentary/roubini37/English" ).
The concern over China acquiring an overall larger GDP than the U.S. is that they can fund a very large military for what they want to do (control that region of the world). That said, I do not think they will surpass the U.S.'s GDP. All of these nations, during their growth phases, can gain an aura of invincibility. It happened to the United States even during the 2000s, when economist Ben Bernanke gave a speech talking about how we had entered a "new era" in which major recessions were a thing of the past and so forth, Dubai thought they were invincible, Japan thought they were invincible during the 1980s, Ireland thought they were invincible, etc...people thought the Soviet Union was leaving us in the dust even. I also do not buy that the Chinese government takes into account the long-term as opposed to the short-term as our politicians do. Enacting such a big stimulus as they did, the fact that the local Chinese governments have economic growth targets to meet, along with corruption in the Chinese government and state-run Chinese enterprises, etc...none of that indicates taking into account the long-term. Recently, China's government has had to assume the liability for about $308-$463 billion worth of bad loans from the local and regional Chinese governments (http://www.cnbc.com/id/43228404/China_s_Enormous_Local_Government_Bailout" )
I think China's government is scared to death of a major uprising in the country. That is why it pushed through that massive infrastructure stimulus and why they have been censoring heavily in the country regarding the uprisings in the Middle East. China has no social safety nets of any kind. They have ethnic tensions in the country as well. If the economy stalls big time, then things could really explode beyond the ability of the Communist Party to control them.
An interesting "bubble indicator" as well is those who say it is not a bubble. Well, they "could" be right, but I mean that is whwat has been said about almost every major bubble in history. You look at Japan in the 1980s, the Soviet Union, the Dot Com bubble, the real-estate bubble of the 2000s, etc...you could find very smart people (economists, investors, traders, etc...) who could give a good, detailed argument on why "This time, it's different!" We see some doing the same with China right now.
Another interesting thing regards skyscrapers and art. Alongside Japan's real-estate bubble during the 1980s was a massive art bubble. And, in addition to an apparent massive real-estate bubble, China also is undergoing a big art bubble as well:
http://www.thedailybeast.com/articl...about-to-burst-says-vikram-mansharamani.html"
Regarding skyscrapers, the construction of very tall skyscrapers has also often served historically as a great bubble indicator. Right now, five of the ten tallest buildings are under construction in China:
http://www.forbes.com/2011/03/10/skyscrapers-burj-dubai-leadership-leaders-bubbles.html"
http://finance.yahoo.com/tech-ticker/look-out-below-why-skyscrapers-are-classic-bubble-indicators-536048.html"
Here are some interesting reads on China:
http://www.zerohedge.com/article/gmos-edward-chancellor-discusses-chinas-red-flags-must-read-fresh-perspective-chinas-bubble"
http://seekingalpha.com/article/259775-china-is-not-a-bubble-it-s-the-hindenburg"
http://www.businessinsider.com/pictures-chinese-ghost-cities-2010-12?slop=1#"
http://www.businessinsider.com/there-are-now-enough-vacant-properties-in-china-to-house-over-half-of-america-2010-9"
http://www.businessinsider.com/the-...bble-is-the-most-obvious-bubble-ever-2010-1#"
http://www.cnbc.com/id/43639266/Why_China_s_Local_Government_Debt_Is_So_Scary"
http://www.bbc.co.uk/news/business-14836386"
http://www.reuters.com/article/2011/07/05/us-china-debt-moodys-idUSTRE7640EN20110705"
http://economictimes.indiatimes.com/news/international-business/chinas-hidden-debt-undermines-its-sermons/articleshow/9911609.cms"
China has some major demographic problems regarding an aging population and because of killing so many of their female babies, a big problem of a severe shortage of available women for the men, major problems with pollution (they have no pollution controls on their industry), major problems with lack of quality control (they build garbage infrastructure apparently, LITERALLY---see the http://www.weirdasianews.com/2010/02/05/shanghai-wonderbridge-trash-collapses/" ), lack of food safety and worker safety standards and regulations, etc...
Also a video:
http://www.youtube.com/watch?v=rPILhiTJv7E&feature=player_embedded
I just find it hard to believe with all this going on that they are going to keep chugging along, increasing in GDP output, and blow by the United States. The Chinese government cannot circumvent the laws of economics, even though they have tricked quite a few into thinking they can it seems.