proposal

How Would North Korea and China Use Nuclear Weapons?
Scenarios for Discussion

Narushige Michishita

This article presents some scenarios in which North Korea and China use nuclear weapons. It outlines the objectives, means, locations, targets, expected damage, and limits, as well as possible negative effects of different types of nuclear weapons use. The descriptions and assessments of those scenarios are based entirely on the author's knowledge and judgments rather than specific evidence. The probability figures assigned to each scenario are defined as the likelihood that the relevant type of nuclear weapons use will take place within the next 20 years. Again, those figures are based on the author's judgment.

This article aims to furnish a common understanding within security communities in concerned countries regarding the scenarios and assessments of nuclear weapons use by North Korea and China. If this article helps bolster discussions on that issue, it will have achieved its purpose. If there is a certain level of consensus on how North Korea and China might use nuclear weapons, the United States, Japan, South Korea, Taiwan, and other countries in the world can engage in discussions on how to address the nuclear challenges posed by North Korea and China.

With the outbreak of war in Ukraine in 2022 and Russian President Vladimir Putin's suggestion of the possible use of nuclear weapons, the possibility of China's nuclear use in the event of a Cross-Strait conflict is becoming an important topic of discussion in the US security community. However, most of the scenarios discussed in the United States involve China using nuclear weapons against the United States. For example, in a May 2022 paper, Stacy Pettyjohn and Becca Wasser presented a scenario in which China detonates a nuclear weapon off the coast of Hawaii as a threat to prevent US intervention in a Cross-Strait conflict. 1 In addition, a wargame conducted in the summer of 2022 by the Center for a New American Security showed China conducting an atmospheric nuclear test inside its territory and then attacking a US military base in Guam with a low-yield nuclear weapon. The atmospheric nuclear tests were intended to pose a threat to the United States and to increase the credibility of China's nuclear threats. The attack on Guam was intended to retaliate against a US attack on the Chinese mainland and to force the United States to get out of the war. 2

In reality, however, if North Korea or China are to use nuclear weapons against other countries, it would likely be against South Korea, Japan, and Taiwan, which do not possess nuclear weapons. The scenarios presented in this paper assume that North Korea and China would avoid using nuclear weapons against the United States. Understandably, security specialists tend to focus on threats to their own country. In that sense, it would be useful for experts from various countries to present various scenarios of nuclear use from their perspectives and discuss how nuclear weapons might be used, how likely each scenario is, and what kind of countermeasures we might be able to develop.

This article first discusses the current status of North Korea's nuclear and missile capabilities, and lists and evaluates five scenarios for the country's use of nuclear weapons. It will then review China's nuclear and missile capabilities, and lay out three scenarios for China's use of nuclear weapons. I hope that those scenarios will provide a useful basis for future discussions among policymakers and security specialists.

1 North Korea

(1) Nuclear Weapons and Delivery Means

The Institute for Science and International Security based in Washington, DC estimates that North Korea possessed between 35 and 63 nuclear weapons as of December 2022, while the Stockholm International Peace Research Institute estimates, as of January 2022, that North Korea possessed approximately 20 nuclear weapons and sufficient fissile material for 45 to 55 nuclear devices. 3 In the 12 years following its first detonation test in 2006, North Korea has conducted six nuclear tests, with explosion yield increasing steadily from less than 1 kiloton in the first test to 160 kilotons in the sixth test. 4 North Korea has also miniaturized its nuclear weapons and has probably mounted them on ballistic missiles. The sixth North Korean nuclear test appears to have involved a hydrogen bomb, given the dramatic increase in explosion yield over previous tests. North Korea characterized its sixth test as "a test of H-bomb for ICBM [intercontinental ballistic missile]" and "a very significant occasion in attaining the final goal of completing the state nuclear force." 5

North Korea maintains some 700 to 1,000 ballistic missiles, of which 45 percent are short-range missiles targeted at South Korea, another 45 percent are medium-range missiles targeted at Japan, and the remaining 10 percent are intermediate- to long-range missiles targeted at the United States. 6 Many of those missiles are operated on mobile launchers. 7 North Korea continues to develop and test new types of missiles and has steadily improved its missile technology and operational capabilities. In the first half of 2023, Pyongyang also revealed that it was developing and testing unmanned underwater nuclear attack craft, or underwater nuclear drones, called Haeil (Tsunami) 1 (submerged range: 600 kilometers) and Haeil 2 (submerged range: 1000 kilometers). 8

(2) Scenarios

Scenario 1: Technological Evaluation and Brinkmanship Diplomacy (Probability: 40%)

As part of a nuclear test and brinkmanship diplomacy, North Korea detonates nuclear weapons underwater in the Sea of Japan and/or in the air over the Pacific Ocean.

Objectives:

Prove the technology and effectiveness of underwater nuclear drones and nuclear-armed ballistic missiles, and make adjustments if necessary;

Enhance the role of nuclear weapons as a diplomatic bargaining chip (Previously North Korea has conducted six underground nuclear tests. Conducting another underground would have limited psychological impact.);

Resume US-North Korea talks and other diplomatic communications;

Discourage foreign submarines from operating near North Korea's coasts.

Means:

Underwater nuclear drones under development;

Intermediate-range ballistic missiles (to reach the Pacific Ocean).

Locations:

Inside North Korea's territorial waters in the Sea of Japan (This allows North Korea to claim it as a legitimate exercise of sovereignty. North Korea understands that conducting a test in the Yellow Sea would upset China, and therefore will avoid this.);

Over the Pacific Ocean in areas without islands or maritime traffic (In 2017, Kim Jong-un mentioned the possibility of taking the "highest level of hard-line countermeasure in history" against the United States. 9 Foreign Minister Ri Yong-ho later said that the "highest level of hard-line countermeasure" could mean a hydrogen bomb test over the Pacific Ocean.).

Military/Civilian Targets:

None. Demonstrations only.

Expected Damage:

Radiation contamination and environmental destruction; 10

A potential risk of unintended damage to foreign countries' submarines.

Limits and Negative Effects:

North Korea's underwater nuclear drones malfunction and ballistic missiles get shot down;

Resumption of US-North Korea dialogue becomes even more difficult;

Deterioration in China-North Korea relations;

Additional sanctions are imposed (although their effectiveness will be limited as North Korea is already isolated).

Scenario 2: Hit-and-Run Attacks against South Korea (Probability: 20%)

North Korea conducts serious military attacks such as firing hundreds of artillery shells, rockets, and conventionally-armed missiles against military bases, industrial areas, and major cities in South Korea. North Korea immediately calls for a ceasefire. North Korea threatens to use nuclear weapons and demands that South Korea not retaliate. If South Korea retaliates, North Korea would detonate nuclear bombs underwater and/or in the air and call for an immediate ceasefire.

Objectives:

Escalate to de-escalate;

Gain the upper hand in the inter-Korean competition; (If both sides fire the same amount of artillery, rockets, and missiles at each other, South Korea, which has more to lose, will suffer more in relative terms. Investors could pull their money from South Korea, for example.)

Undermine South Korea's position in the world and teach a "lesson" to conservative South Korean political leaders.

Means:

Underwater nuclear drones;

Short-range ballistic missiles with maneuverable low-yield nuclear warheads (to avoid interception), such as KN-23s, or improved Hwasong-11s.

Location:

Sea of Japan

Military/Civilian Targets:

None. Demonstrations only.

Expected Damage:

Radiation contamination and environmental destruction;

A potential risk of unintended damage to foreign countries' submarines.

Limits and Negative Effects:

North Korea's ballistic missiles malfunction or get shot down;

North Korea becomes unstable as a result of armed conflict;

The United States strengthens its extended nuclear deterrence;

Deterioration in China-North Korea relations;

Further strengthening of South Korea's and Japan's military capabilities, and the rise in their demands for independent nuclear forces.

Scenario 3: Forming a Second Front in a Cross-Strait Conflict (Intra-War Probability: 10%)

A conflict erupts in the Taiwan Strait, and the United States and Japan deploy their forces there. China requests North Korea to conduct limited but sustained strikes against South Korea while promising full military and diplomatic support. In response, North Korea takes limited but sustained military actions against South Korea, including artillery, rocket, and missile attacks. Fearing an escalation of the situation, the United States and South Korea carry out retaliatory strikes against North Korea in a limited fashion. However, as the engagement continues, people in South Korea start to demand a stronger retaliation. In response, North Korea announces, "If South Korea escalates the situation, we will be forced to use nuclear weapons to prevent the war from escalating." If South Korea nevertheless takes strong countermeasures against North Korea, North Korea will detonate a nuclear weapon underwater or in the air in the Sea of Japan off South Korea's east coast, escalating to de-escalate. In this scenario, the probability of North Korea using nuclear weapons is not as high as in the previous scenario because of China's backing and the US and Japan's reluctance to fight a two-front war on the Korean Peninsula and in the Taiwan Strait.

Objectives:

Gain the upper hand in the inter-Korean competition;

Support China by diverting US and Japanese forces away from the Taiwan Strait;

Enhance the effectiveness of China's nuclear coercion against the United States and Japan;

Occupy an advantageous position as China's ally as China unifies Taiwan by force and establishes regional hegemony.

Means:

Underwater nuclear drones;

Short-range ballistic missiles with maneuverable low-yield nuclear warheads.

Location:

Sea of Japan

Military/Civilian Targets:

None.

Expected Damage:

Radiation contamination and environmental destruction;

A potential risk of unintended damage to foreign countries' submarines.

Limits and Negative Effects:

North Korea's nuclear ballistic missile might get shot down;

North Korea becomes unstable as a result of armed conflict;

China might fail to unify Taiwan. (If that happens, China might become unstable domestically and isolated internationally, putting North Korea in a difficult position. In the worst case, it would lead to the collapse of the North Korean regime.)

Scenario 4: Preventing South Korea-led Unification (Probability: 5%)

The political and socioeconomic situation in North Korea deteriorates and South Korea decides to intervene militarily. Pyongyang decides to use low-yield nuclear weapons to prevent South Korean forces from occupying the northern half of the peninsula. (The probability of this scenario is low because South Korea is not likely to intervene forcibly. Not many South Korean citizens desire unification and the risks associated with North Korea's response would be high.)

Objectives:

Prevent Korean unification under the South Korean leadership;

Keep Korea divided and maintain the North Korean regime.

Means:

Short-range ballistic missiles with maneuverable low-yield nuclear warheads.

Locations:

In and near the Demilitarized Zone (DMZ).

Military/Civilian Targets:

South Korean armed forces.

Expected Damage:

Significant damage to South Korean forces and limited collateral damage in both Koreas.

Limits and Negative Effects:

North Korea's nuclear ballistic missiles malfunction or get shot down;

South Korea-led armed unification through a counteroffensive conducted by US and South Korean combined forces.

Scenario 5: Kim's Mass Murder-Suicide (Probability: 3%)

Kim Jong-un faces an imminent regime collapse due to a palace or military coup. Desperate, Kim resorts to self-destruction, conducting all-out nuclear attacks against South Korea, Japan, and the United States, taking them down with him. (The probability of this scenario is very low because Kim Jong-un reaching a state of desperation implies that he has already lost control of his military command.)

Objectives:

Destroy neighboring countries;

Take revenge on South Korea for defeating North Korea's legitimacy, on Japan for its historic colonization of Korea, and on the United States for its "hostile policy" towards Pyongyang.

Means:

All available nuclear forces.

Locations:

South Korea, Japan, and the United States.

Military/Civilian Targets:

Major cities in South Korea, Japan, and the United States.

Expected Damage:

Severe and extensive human and physical damage.

Limits and Negative Effects:

The United States and South Korea could successfully preempt and intercept most of North Korea's nuclear attacks with various means including the use of US nuclear weapons. Japan could also participate in missile defense and, possibly, strike operations. The three countries would seek to minimize casualties with robust civil defense measures. South Korea could use the opportunity to unify the Korean Peninsula.

2 China

(1) Nuclear Weapons and Delivery Means

In 2021, China's operational nuclear warheads stockpile was assessed to have surpassed 400. If China keeps expanding its nuclear forces at the current pace, it will likely field about 1,500 nuclear warheads by 2035. China has also deployed more than 600 short-range ballistic missiles with a range of 300 to 1,000 kilometers, over 500 medium-range ballistic missiles with a range of 1,000 to 3,000 kilometers, and more than 250 intermediate-range ballistic missiles with a range of 3,000 to 5,500 kilometers. It also possesses 300 intercontinental ballistic missiles with a range of 5,500 kilometers or more, and over 300 ground-launched cruise missiles with a range of 1,500 kilometers or more. 11 In 2021, China is assessed to have launched 135 ballistic missiles for testing and training purposes. That was more than the number of missiles launched outside of China, excluding those launched in conflicts. 12

China is estimated to possess approximately 60 nuclear weapons for tactical missions in the Indo-Pacific region. The missiles capable of delivering those tactical nuclear weapons include the DF-21A/E ballistic missile (with a range of over 2,100 kilometers and at least 40 mobile launchers), DF-26 ballistic missile (with a range of 4,000 kilometers operated on 200 mobile launchers, of which approximately 20 are designated for nuclear operation; an anti-ship version is also available), and DF-17 ballistic missile with a hypersonic glide vehicle (with a range of over 1,800 kilometers operated on at least 16 mobile launchers). It is believed that the DF-15 ballistic missile (with a range of 600 kilometers) can carry nuclear warheads, but there is no evidence of actual nuclear deployment. While it cannot be ruled out that China's cruise missiles are capable of carrying nuclear weapons, they are not currently engaged in substantive nuclear operations. Finally, due to the lack of capable delivery means, the Chinese air force's nuclear mission is limited, with only around 20 nuclear gravity bombs in its possession. 13

(2) Scenarios

Scenario 1: Neutralizing Japan and, possibly, the United States in the Cross-Strait War

(Intra-War Probability: 50%)

China launches an attack on Taiwan and strongly warns the United States and Japan against military intervention, detonating nuclear weapons at sea. If the United States and Japan continue to provide support to Taiwan despite the warnings, China launches tactical nuclear strikes against the Japan Maritime Self-Defense Force's surface vessels. Relatively small vessels are targeted at first, but if US and Japanese intervention continues, larger vessels become targets. Moreover, Beijing declares that if the United States retaliates with nuclear weapons against China, it will launch further nuclear attacks against Japanese assets and even territory. The goal is to encourage Japan to ask the United States not to retaliate with nuclear weapons. China never uses nuclear weapons against the United States. China can also use nuclear weapons against the Japan Ground Self-Defense Force's anti-ship missile units deployed in the Southwestern (Nansei) Islands such as Miyako and Ishigaki.

Objectives:

Neutralize Japan; (If Tokyo does not allow the United States to use its bases in Japan and decides not to commit the Self-Defense Forces to the Cross-Strait war, that would make the defense of Taiwan extremely difficult. The United States would find it difficult to fight effectively without Japan's help and might decide to abandon Taiwan. Even if Japan is not completely neutralized, limiting its commitment will help China.)

Make it difficult for the United States to operate its aircraft carriers near Taiwan;

Neutralize the United States, if possible.

Means:

DF-21A/E ballistic missiles (detonation at sea and Southwestern Islands attacks);

DF-26 ballistic missiles (anti-ship operations);

Possibly DF-17 hypersonic glide missiles.

Locations:

Western Pacific east of the First Island Chain (where US-Japan missile defense assets are not densely deployed).

Military/Civilian Targets:

Demonstration purposes only at first;

The Japan Self-Defense Force's surface vessels and anti-ship missile units.

Expected Damage:

Approximately 100 sailors on small surface combatants and some 500 on large surface combatants;

About 570 Japanese army personnel in Ishigaki and about 700 in Miyako;

Minimal collateral damage for civilians.

Limits and Negative Effects:

The United States and Japan could successfully intercept China's ballistic missiles, undercutting the effectiveness of China's nuclear coercion;

The United States, with its superior nuclear capabilities, could dominate each stage of escalation with aggressive nuclear use.

Scenario 2: Nuclear Use for Victory (Intra-War Probability: 30%)

China uses tactical nuclear weapons against areas along Taiwan's west coast where Chinese forces are expected to land. Taiwan's defense systems and other assets will be destroyed. In addition, China conducts nuclear strikes against key Taiwanese and Japanese military assets at sea and on land without harming US personnel or assets. Even if Taiwan is nuked, the threshold will be high for the United States to carry out nuclear retaliation against the Chinese mainland. While the use of nuclear weapons would likely divide public opinion in the United States and other Western societies, it would not cause major political problems in China. The Chinese government might even take pride in making China the second country in the world to use nuclear weapons in war and present that as a symbolic event in China's rise to hegemony. If China uses nuclear weapons tactically, it will justify that as part of its effort to defy "foreign interference in the internal affairs of the Chinese nation."

Objectives:

Destroy Taiwan's defense capabilities;

Minimize attrition of Chinese amphibious landing forces;

Break Japan's ability and willingness to continue the war.

Means:

DF-21A/E ballistic missiles (detonation at sea and Southwestern Islands attacks);

DF-26 ballistic missiles (anti-ship operations);

Possibly DF-17 hypersonic glide missiles.

Locations:

Western Pacific;

Taiwanese and Japanese territories.

Military/Civilian Targets:

Taiwan's and Japan's military assets.

Expected Damage:

Numerous casualties among Taiwanese military personnel and limited collateral damage to civilians;

Approximately 100 sailors on small surface combatants and some 500 on large surface combatants;

About 570 Japanese army personnel in Ishigaki and about 700 in Miyako.

Limits and Negative Effects:

The United States and Japan could successfully intercept China's ballistic missiles;

The United States might use tactical nuclear weapons against China's military assets such as amphibious landing forces.

Scenario 3: Face-Saving Way Out (Probability when China becomes convinced of its defeat: 20%)

Having failed to take Taiwan by force, China launches a single nuclear attack on a key Taiwanese military base located in an area with a small civilian population for the stated purpose of "punishing the separatists and teaching them a lesson." The Chinese leaders take such an action to end the war while saving their face. They then immediately declare a ceasefire and withdraw their forces, claiming that their patriotic venture to unify the Chinese nation was frustrated by "American imperialists, Japanese militarists, and Taiwanese separatists."

Objectives:

Accept the failure of the invasion of Taiwan in a dignified manner;

Keep China's neighbors on the defensive;

Make leaders of the Chinese Communist Party and the People's Liberation Army complicit in the inhumane act of using nuclear weapons lest they betray the top leader.

Means:

DF-21A/E ballistic missiles;

DF-26 ballistic missiles;

Possibly DF-17 hypersonic glide missiles.

Locations:

Taiwan

Military/Civilian Targets:

Critical base or infrastructure of Taiwanese military.

Expected Damage:

Destruction of military installations and a significant number of Taiwanese service member casualties.

Limits and Negative Effects:

The United States and Japan could successfully intercept China's ballistic missiles;

China will become isolated in the international community (although there will be a limit since isolating China too much can be counterproductive and economic interdependence will remain);

People in Taiwan will become disillusioned by China, and few will remain willing to see the unification of the Chinese nation.

Acknowledgments

I would like to express my deepest gratitude to Mr. Masashi Murano of the Hudson Institute for his valuable comments on my scenarios and to Ms. Ariel Stenek of the National Graduate Institute for Policy Studies for editorial support.

Narushige Michishita is an executive vice president and professor at the National Graduate Institute for Policy Studies (GRIPS) in Tokyo. He can be reached at michi@grips.ac.jp.

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