The key trait about Britain’s empire was it’s utter naval supremacy, policy and fact was that it had to be able to fight the next two biggest navies at once and win, and the USA’s empire also has command of the seas, mostly because the USSR was a land power. China, while it could certainly gain command of the seas, isn’t a similar naval power (Japan has a similarly sized navy) and three important trends exist to complicate things. First is peak oil and from it the decline in fuel availability for navies, this is already limiting anti-piracy operations, and ocean transport is being similarly affected. Second is the diffusion of naval power, effectively many powers are building up their navies, significantly India and Iran since they can easily shut down or control major sea routes (Persian Gulf and the Malacca Strait), notably where most of China’s oil goes through. Thirdly is the rise of missile technology and while they haven’t been used to full effect, a missile swarm (50-300) could easily destroy a carrier taskforce (or any other naval taskforce, except submarines), or alternatively they could be turned on transport ships, wether of troops, supplies or cargo. Effectively, missiles have made projecting naval power and moving military forces via the sea harder and almost impossible against a serious, tech capable and prepared defender, once they’re finally used this aspect will become quite clear.
Now, these three trends aren’t insurmountable and China could still end up dominating most of the world’s oceans. A mixture of stockpiling, preparation and an active approach by the government to lower oil use to save for future military use can counter the first trend. The second trend can be solved by increased military build-ups or solid alliances but that’s prohibitively expensive or difficult, a more likely approach is that China will limit its scope of control to important sea lanes (from its point of view) and gain the alliances of several other major naval powers, note that the sea lanes China uses aren’t the ones we use. The third trend is harder to counter, and while its always possible that some new technology will solve it (If a certain trend holds they will, when its to late), I wouldn’t hold my breath. Soft power will certainly become more important and having steadfast allies on all continents would help, however those methods aren’t anywhere near as reliable, especially without adequate hard power to back them up. In summary, while it is possible for the Chinese to gain total dominance of the seas, its unlikely and it’s instead likely to be restricted to the important sea lanes (for China) with many sections of the world’s sea under regional naval powers instead and others under the other large naval powers.
Another important detail, which is directly related to overshoot, is that of technological superiority. Naval warfare is highly technical in nature, and only small advantages in technology are needed to completely change the strategic and tactical landscape. The Romans before they fought Carthage had absolutely no experience as a naval power and while they did have a few client cities with a strong naval tradition, those cities lacked the numbers and industry to significantly contribute to challenging Carthage (who ruled the Mediterranean back then). So what happened that allowed Rome to destroy Carthage’s navy and dominate the Mediterranean in just 20 years; One they confiscated a Carthaginian quinquereme that had run aground, they then it used to design their fleet of 120 ships the they built in 2 months. Later on they bested that feat and built a bigger navy when a storm wrecked the first one. Two, to make up for their lack of maritime skill and the lack of manuverability this caused, since ramming was the dominate tactic back then, they invented the Corvus, basically a giant plank on a swivel table with a spike in it (a.k.a a boarding bridge) and used their legionaries at sea. The battle of Lepanto had a similar dynamic where the modern but outnumbered Holy League fleet destroyed or captured 200 of the Ottomans 275 strong fleet while only losing 15 ships. The victory in what turned into a large slugging match happened because the Holy League had 1815 cannons while the Ottomans had only 750 cannons, they also ran out of gunpowder. Another advantage to the Holy League also had 6 galleass (midway between a galley and a man-o-war) which were said to sink 70 galleys by themselves (while they were several miles in front of the holy league fleet). The conditions that allowed Britain and the USA to keep naval superiority don’t exist anymore, while Britain didn’t always innovate itself, due to its huge industrial might it could put any innovation into large scale action first and the USA navy has massive funding. China will have many industrial opponents capable of innovation and implementation and one of the key traits of post-peak naval warfare will be technological flux, meaning global naval superiority is out of China’s reach. Also Britain main rival France never had the skilled sailors necessary to fight Britain openly and the USSR was a land based power, while China is a land power with a strengthening but not unusually big naval culture (which can be very important) and some of its opponents have a strong maritime tradition.
Heres a what I remember of a short sci-fi story to illustrate the differences between the army and the navy. The imperium is subjugating some natives on the planet and an Admiral and a General are walking along having a chat. Suddenly a hover car zooms by them with a spear sticking out of it and the Admiral exclaims ‘how can we lose against someone who can only throw spears at a hover car’. The General responds by saying ‘how can we win against someone willing to throw spears at a hover car’.
Now, why are those details important? Because of the answer to our previous question of why the link Between Australia and then Britain and now the USA is like it is. Link. None of our strategic concerns are territorial, their all to do with trade routes, specifically maritime. Since Britain and the USA controlled the seas, aligning with them made perfect sense and so that’s what we did. But China’s (or any other potential empires) empire’s position isn’t anywhere near as strong in naval terms and since Overshoot is already limiting modern navies ability to police the seas (which is their main job, even during war), that deal cannot exist in as strong a form as it historically has. So, how strong could our relationship with China be?