While it is possible to reverse the decline, China is now in a different demographic regime than in those centuries where the population stayed mostly even.
The regime then was high fertility and high mortality. Now, it's low and low, and both the fertility and mortality declines have strong economic, institutional and cultural drivers.
In geographic terms for example, people live very differently. Then, most people lived on farms with or near their extended family, surviving (often malnourished) by arduous work that mostly wore out joints and tendons by age 50. Now, most people are in nuclear families or single-adult households in cities, much better nourished and housed and expending fewer Calories per day.
Economic progress has also given people more agency and more possibilities, and quite a few are choosing, for example, to maintain career momentum rather than take time out to have children.
At the same time the costs (in both money and time) of raising children to be economically productive are rising rapidly and there are other large demands on Chinese families' income - housing, healthcare and saving for their own retirement,* for example.
It's possible that some government policies might lift fertility (in particular, a universal pension, cheap universal healthcare, and laws about career momentum with children) but imho these policies will only be tried some decades after a one-child or no-child household has become firmly entrenched in the culture. That is, too late.
* Nearly everyone wants to avoid a precipitous drop in standard of living on retirement. China has very low retirement ages: 55 for women and 60 for men, IIRC. And there is no socila security. With fewer income earning years, people have to save a bigger proportion of their income.
Sidebar: in a low mortality regime, the key demographic statistic for long run population growth or decline is the reproduction ratio (RR), the number of daughters per woman. In the past demographers have used the easier-to-obtain Total Fertility Rate (TFR, lifetime number of children per woman if this year's number of babies per 100,000 population were to remain constant) or CCF50 (completed cohort fertility at age 50) which counts the number of children 50-year-old women have had.
The assumption was that there is a fixed relationship between RR and TFR and/or CCF50. Now that fetal gender selection is being practised, the relationship is no longer so fixed. So things are worse for China than they might appear using simple whole-population numbers.
Everything in life is on average 50% genetics, and nature has a way of weeding out those who have a lower propensity to reproduce. I wouldn't worry at all about population declines in and of themselves.
All over the world, we have transitioned from more traditional societies to more liberated societies that are failing to reproduce. That collapse in fertility goes lockstep with modernism. As a fun fact: there were studies that in 19th C France those postal codes in which large numbers of Diderot's encyclopedia were sold saw rapid fertility drops. Something about modernism is incompatible with human reproduction, so either we will evolve to thrive in the more liberal societies, or the future will belong to those subpopulations that reject modernity, whether orthodox jews in Israel or Amish in the US, or more fundamentalist islamic groups in the middle east, which have already taken over the dead carcasses of modern secular societies that thrived in the 60s and 70s. So either modernism will die or people will evolve to have more kids in modernist societies, but in either case, population will be increasing again in the future, which belongs, as the old saw goes, to those who show up. Eventually there will be a harmonization where our environment is suitable for reproduction.
But still, I think if it became necessary, governments could offer a one time cash payment of 50,000 dollars per child and that would send birth rates up pretty fast. That’s not free though. I see what you’re saying about it being a different situation now, and you’re right, it is.
There are about 4,000,000 live births in the USA every year; paying 50,000 for each of them would cost 200 billion, which is less than a third of the military budget, not cheap, but doable.
If you reduce the number of people, the GDP is spread over fewer people and the GDP per head is higher.
The strange thing is a census need to be waited. Is it a fact or ...?
China.
Btw I am not thinking about the rumour there is usual amount of death as well. Can’t be ... can it?
China has GDP per capita below Costa Rica[0], and yet can determine actions and statements made by enormous US organizations like NBA [1], and in knock-on effects, statements made by Disney-owned ESPN about statements made and subsequently disowned by NBA [2]. Multi-national organizations don't think twice about Costa Rica.
Matthew Yglesias makes the case in a recent book that the US should embrace all the ways that the country is able to continue growing while China's, and many other countries', populations stagnate and decline.[3]
[0] https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(nomi... [1] https://www.npr.org/2019/10/31/774985504/the-nba-and-hong-ko... [2] https://www.fool.com/investing/2020/10/22/is-disney-relation... [3] https://www.econlib.org/reflections-on-one-billion-americans...
Only half the population has access to safe drinking water, and only 10% has access to household sewage treatment. 43% of the waterways are unfit for human contact, and 90% of the cities have poisoned their own water tables. The following article has pages of statistics like this.
http://factsanddetails.com/china/cat10/sub66/item391.html
The air pollution is at least as bad.
China is a large enough percentage of the earth’s surface area to make these global problems.
But it does not seem to have (yet) significantly impacted population decline for now.