They have Numerous separatists and cession movements, the most prominent one being the East Turkestan Independence Movement,
however, attacks are down in the past few years. members and actors affiliated with the East Turkestan Independence Movement have carried out multiple terror attacks, such as the April 2014 Ürümqi attack, 2011 Kashgar attacks, and the 2011 Hotan Attack
International pressure, In the past few years, China has procured a ”Wolf Warrior” diplomacy stance, causing its diplomats to be harsh and deny accusations against the Chinese state. China is also damming up the Brahmaputra, the Indus, and destroying the Mekong. Which will further hurt their diplomatic and geopolitical status with India, their biggest rival in their immediate vicinity.
China confronts a uniquely challenging geography. It is bordered by 14 countries, four of which are nuclear armed and five of which harbor unresolved territorial disputes with Beijing. These include an aging but wealthy Japan, a rising and nationalistic India, a revanchist Russia, a technologically powerful South Korea, and a determined Vietnam. All these countries have national identities that resist subordination to China or its interests. And the United States maintains a constant forward-deployed military presence in the region. Biden can work with these countries in the military sector, multiple bases in Japan, a technological SK which can be leveraged, and border stances by SCS countries can be assisted with US patrols and deployments.
By Pr0-metheu5
From Russia's side: Not a good option at all, but seen more as inevitability than anything else. The main detractors of the idea are Putin's more liberal friends, who believe Russia is a firmly European country and has no business falling into China's sphere of influence. It's also opposed by a small cluster of siloviki, who believe that China will devour Russia as wasteland of natural resources, and will use it as a bargaining chip at the first convenience. So, there's concerns about appropriateness of the relationship and who will be junior partner. The latter part might become absolutely crucial, as one of the main reasons Putin, who used to be fairly pro-western, grew disillusioned with the west is that he held that he was being treated as the "junior partner" in the relationship. It would be a sour grapes situation, since it's back to square one, but youre not even with preferred bedfellows. One need not forget that this is Russia, here. People still remember how the USSR (which, I insist, was not just "Russia by another name", but that's for another time) dictated to the world its terms. It'd be hard to go from that to being "the term-dictator's oil-rich neighbor." A lot of the inside-Russia academic types are really hoping it is just a spook story to use against a west fearful of consolidating threats.
The complicator: Central Asia... Russian and Chinese interests are at total odds here and a friction point is waiting to pop up.
By 2040 China will require more natural resources than the world combined, and their massive military spending will drag down their economy, and pollution is getting worse. Their belt and road project and their infrastructure investments are just draining money. Not to mention international pressure from the outside world, most notably US, Japan, SK, and India. Their aggressiveness with ASEAN and the South China Sea, Taiwan, and India will only further complicate and negatively impact their diplomatic and immediate status.
China has an enormous Housing bubble and shoddy infrastructure, the most significant being the three gorges dam, which has possibly warped. They also need to deal with ecological problems caused by climate change such as desertification, food and water problems caused by their growing population rapid economic development, and again, climate change. However, China has done great progress towards green technology,
https://blogs.ei.columbia.edu/2011/05/05/how-china-is-dealing-with-its-water-crisis/
https://www.rapidtransition.org/stories/how-china-brought-its-forests-back-to-life-in-a-decade/
https://www.nytimes.com/2020/09/23/world/asia/china-climate-change.html
They want people to be in conflict with each other.
Their GDP growth is bigger than it was a decade ago but has been slowing in recent years as major importers move either to India or domestic manufacturing.
Will China overtake the US per capita? probably not in this century. I am just saying in total size, 4x more people is highly likely if not almost certainly will overtake a country with 4x less people.
https://youtu.be/h7wZOGtsOWg- Is China the Next World Power?