This article speculates that rather than worrying about the rise of Chinese power causing war, we should worry about China's decline:
What will be the geopolitical implications for China, its neighbors and the United States if the Chinese economy tanks? Would China be taken off of its supposed collision course, or would conflict remain unavoidable? ...
Which brings us to our second theory—one that I believe is more likely to materialize. This theory posits that an economic downturn in China will cause a crisis in legitimacy for the Chinese Communist Party, who will in turn point to external threats to bolster its internal legitimacy. China’s leaders, in other words, will play the nationalism card, perhaps provoking an international conflagration in one or more of the aforementioned flashpoints.
Indeed. While China's economic growth has been substantial, I don't think it can be sustained.
In the long run, we may be just fine compared to China's now-predicted rise to dominance.
I don't get too worked up over the PPP comparison since it is essentially a scoring handicap for Third World economies compared to advanced economies. Raw GDP is still the way one has weight in the international community which doesn't really care that someone in China pays less for a cup of coffee at their corner shop than we do. This measuring stick has uses, of course, as does per-capita comparisons.
For example, defense spending comparisons greatly under-estimate China's spending by failing to consider how much cheaper it is to field and equip a Chinese solder by PPP measures (in addition to the other personnel costs that we endure plus spending categories involved with projecting power globally that other countries don't have).
But notwithstanding the real achievement of this milestone, if China's economic problems are really bad enough to threaten the growth that got China to this point, the chance of China's rulers using a foreign flashpoint to bolster their rule is under-estimated by using a Western model of internal versus external policies.
For China's Communist rulers, all problems anywhere are part of a continuum of threats to their rule. So all responses are part of a continuum, too, with no Western break between domestic and foreign actions. There is no particular gap to leap by using an "international conflagration" to stoke nationalistic support for Chinese Communist Party rule in the face of economic difficulties.
Remember, China already says that "foreign" (from our view) territorial disputes with Japan, Taiwan, claimants to South China Sea islands, and India are all actually internal issues of Chinese land that foreigners have no business even talking about.
Of course, if China really does face internal problems serious enough to lead to war, will this shake out as a response by China the country or China the continent?
If conflict really is unavoidable whether China rises of declines as the article says theory predicts, perhaps we will be saved by that internal/exterior model when the Chinese Communist Party finds itself fighting newly external foes that were once internal problems in our thinking.
That may not matter to the party itself with its view of all threats to its rule, but it will matter a great deal to us if the fighting is mostly inside China's current borders.