China releases no official information about its nuclear weapons stockpile. However, according to open-source research, China currently has fewer than 300 nuclear warheads.
Tong Zhao is a fellow in Carnegie’s Nuclear Policy Program based at the Carnegie–Tsinghua Center for Global Policy.
China also has a wide range of nuclear weapon delivery systems. These are mostly ballistic missiles of various ranges, which can carry nuclear warheads to targets around the world.
Unlike those of the United States and Russia, it is commonly believed that China’s nuclear weapons are kept in storage and are not deployed on active alert in peacetime.
Does China have more or fewer nuclear weapons than its peers?
China’s overall nuclear arsenal is at least ten times smaller than those of the United States or Russia. Washington and Moscow each have around 4,000 nuclear weapons in their arsenals, plus thousands more that are retired and waiting to be dismantled.
China’s nuclear stockpile is of a similar scale to those of other medium-sized nuclear weapon states. It seems to be slightly smaller than that of France, which has about 300 warheads, but a bit larger than that of the UK, which has about 215.
Why does China want more nuclear weapons in the first place?
China feels that the credibility of its existing nuclear deterrent is not strong enough.
In other words, Beijing is anxious that other countries are not completely convinced that, if they were to launch a preemptive strike against China’s nuclear weapons, China would be able to strike back and destroy them.
If China only needs enough nuclear weapons to show it can defend itself, why does it want more?
As long as there is a decent chance that some Chinese nuclear weapons could survive a hypothetical hostile first strike and be available for a Chinese counterstrike, Beijing’s deterrent would be credible enough.
The problem is that many Chinese experts have started to worry that this second-strike credibility is eroding. They believe China needs more and better nuclear weapons to show that it could still strike back if attacked.
Their fear is mainly due to new challenges from emerging non-nuclear technologies, such as missile defense and conventional precision strike weapons.
Chinese experts worry that other countries’ conventional weapons are now sophisticated enough to endanger Chinese nuclear weapons, if the other country struck first.
And enemy missile defense could make it harder for China to strike back. This is because any remaining Chinese nuclear missiles that survived a hypothetical first strike would risk being shot down before reaching their targets.
Worse, some U.S. experts have published research that says a first strike by the United States could potentially strip China of any ability to retaliate with nuclear weapons. In light of such research, Beijing is increasingly uneasy and keen to make its nuclear forces more robust, more diverse, and more high-tech.
Does China want to increase the size of its nuclear arsenal overall?
China’s main goal is not to significantly increase its number of nuclear weapons.
Instead, Beijing wants to arm certain submarines with nuclear warheads. The plan is to diversify the structure of its nuclear force and to make sure that each category of nuclear weapons would be as survivable as possible. Essentially, China wants to avoid having all its eggs in one basket.
How many nuclear submarines does China want?
As a rule, China would need at least four nuclear-armed submarines to keep one submarine deployable at all times. This is because the other three submarines would need to undergo regular maintenance and crew training or would be on their way to or from patrol areas.
By the same logic, if Beijing feels it needs to keep at least two nuclear-armed submarines constantly at sea to constitute a credible deterrent, it would have to build at least eight nuclear-armed submarines.
Why do maintenance and refueling take so long?
Submarines need frequent and regular maintenance. In particular, refueling submarine reactors is a time-consuming, expensive process, which typically involves cutting the submarine open.
For example, one type of nuclear-armed submarine, the U.S. Ohio-class model, currently requires a four-year, mid-life overhaul, including a two-year refueling period. Future models of this particular U.S. submarine will have a core that lasts as long as the ship itself, but it is unlikely that Chinese submarines will be so cutting-edge.
Can China just move underwater some of the nuclear weapons it already has on land?
No. These additional warheads cannot simply come from the existing land-based missile force.
This is because land-based missiles are still the most important component of China’s nuclear deterrent. Even if China uses the same type of warheads for its submarine-launched missiles, it cannot afford to risk undermining its land-based deterrent by moving too many of those warheads out to sea.
Why is it a good idea to keep nuclear weapons underwater in the first place?
The mainstream view is that putting nuclear weapons on submarines makes them more likely to survive enemy detection and attack. In most cases, it is harder for an enemy to detect and track submarines in the open ocean than land-based missiles.
Submarine-launched missiles have another benefit. They make it difficult for an enemy to predict where a missile strike may come from. This could make it harder for the enemy to intercept the missiles.
Does putting nuclear weapons underwater make them harder to defend?
It depends. The noisier a submarine is, the more vulnerable it is. That’s because enemy technology can detect where submarines are by the sounds they make. To build and maintain a quiet fleet requires advanced technology and good operational experience. Beijing is still in the process of trying to achieve these standards.
What’s more, putting nuclear weapons on submarines would mean that China is deploying its nuclear weapons outside of its territory for the first time, making them more vulnerable to potential enemies.
How might other countries respond to China getting more nuclear submarines?
Other countries may see China’s growing nuclear submarine fleet as part of an effort to beef up its nuclear forces and to make nuclear weapons a bigger part of the country’s national security strategy.
A new Chinese submarine (Type 094a) that is capable of carrying nuclear warheads
If they believe this to be the case, U.S. allies may rely more on the U.S. nuclear umbrella for their security. This commits the United States to responding with a nuclear counterstrike if a rival were to launch a nuclear attack against one of its allies.
To protect its nuclear-armed submarines, China needs to deploy massive general-purpose forces in its coastal waters to fend off enemy ships and aircraft that could threaten them. Other countries may see this as an aggressive Chinese move to seek regional military dominance. Neighboring countries may increase their security cooperation with the United States, and among themselves, to counter the perceived growth of China’s sphere of influence.
What might be the broader consequences?
A growing Chinese nuclear stockpile may make the United States and Russia more reluctant to reduce their own nuclear arsenals.
If the world’s major powers were to renew their interest in nuclear weapons, this would have a devastating impact on regional and international strategic stability. Everyone would feel a greater need to invest more in their own nuclear weapons and would feel less secure.
Furthermore, by adding more Chinese military patrols to already crowded waters, China’s efforts to protect its submarines and counter U.S. anti-submarine warfare would also make things more tense between conventional military forces. There would be no winner in the end.
Could these dynamics make a nuclear war more likely?
The risk of a nuclear war may increase as a result of unforeseen incidents and unintentional escalations.
One issue is that China’s nuclear-armed submarines could be mistaken for nuclear-powered attack submarines armed with only conventional weapons. Nuclear attack submarines are nuclear-powered, but they do not carry nuclear weapons, whereas nuclear strategic submarines do. A threat to the latter is seen as a much higher-level threat.
In a crisis, for example, the Chinese could misinterpret a U.S. effort to track and trail China’s conventionally armed nuclear attack submarines. They might wrongly believe that the United States was actually preparing for a preemptive strike against China’s nuclear strategic submarines, which probably operate in the same area.
In such a scenario, China might decide to use its nuclear weapons before it believes they will be destroyed, resulting in a nuclear exchange.
The reported lack of reliability in China’s nuclear command, control, and communication system may make such risks even more dangerous. If there were a breakdown in communication in a crisis, it would be more likely that China might misjudge the situation and overact.
What do people in the West not understand about how China thinks about its nuclear deterrent?
President Donald Trump and his administration’s 2018 Nuclear Posture Review portrays China as adopting some sort of escalate to de-escalate strategy—meaning that Beijing supposedly may intend to use nuclear weapons first to intimidate an enemy if China were facing a major defeat in a hypothetical conventional military conflict.
In such an instance, this line of U.S. thinking goes, Washington would have to consider using tactical nuclear weapons to deter or respond to Beijing’s potential use of nuclear weapons.
But there is no evidence that China actually does embrace or is considering such a strategy. On the contrary, Chinese military strategists seem to have incorporated the country’s unconditional no-first-use policy deeply in their military thinking and planning.
This U.S. misunderstanding of China’s nuclear posture could lead to misjudgment and overreaction, which could increase the risk of inadvertent nuclear war.
What should China and other countries do to make a nuclear war less likely?
They need to better understand each other’s nuclear thinking and nuclear postures, and they must avoid exaggerated threat perceptions and overreactions.
They ought to limit the role of nuclear weapons to only deterring the use of nuclear weapons by others, thus minimizing the part nuclear weapons play in their national security strategies.
They should also avoid dangerous nuclear postures, such as putting nuclear forces on high alert during peacetime or allowing nuclear and conventional weapon systems to share the same set of command, control, and communication systems.
Finally, they should give up any plans to incorporate unproven artificial intelligence technologies with nuclear weapons (such as self-navigating nuclear torpedoes) or efforts to use cyber technologies to interfere with each other’s nuclear command, control, and communication systems.