How will China's future senior citizens support themselves? China still has no official national pension system. Up to now, China's de facto national pension system has been the family -- but that social safety net is unraveling, and rapidly. Until very recently, thanks to relatively large Chinese families, almost every Chinese woman had given birth to at least one son -- under Confucian tradition, their first line of support. But just two decades from now, thanks to the "success" of the one-child policy, roughly a third of women entering their 60s will have no living son.
By completely obliterating the traditional Chinese family and replacing it with a new paradigm that threatens the very fabric of their society, what will come of the country? Combining that with the shortage of females and you'll have a generation of men without women. On top of that, paying for all of the seniors who won't have anyone to care for them combine for what could be the perfect storm of problems that will cause China to either collapse under itself or to explode outward. Either way it could be a problem that would rack the very foundations of the current global situation. This would happen either with a monstrous war of conquest searching for some way out or else a humanitarian situation that could make Africa look like Canada. Either way there is a way out and it starts with eliminating the single child policy. After decades of this setup, they won't see the population explosion that you'd expect because everybody is used to just having one child. You will see somewhat of an uptick, however it will be relatively mild due to the increasing industrialization of the country. The bottom line is that a policy like this, carried indefinitely, will lead to the extinction of a society. That's not good for anyone, least of all, the Chinese.