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The contemporary global security environment is characterized by a dynamic interplay of traditional geopolitical rivalries, accelerating technological advancements, and emergent non-traditional threats. This complex tapestry presents a security landscape far more intricate than previous eras, demanding a nuanced understanding of interconnected risks. The proliferation and modernization of nuclear arsenals, coupled with shifts in strategic doctrines, underscore a heightened state of global military readiness. Concurrently, pervasive challenges such as climate change, resource scarcity, and economic disruptions contribute to societal instability, creating new pathways for conflict. The rapid evolution of artificial intelligence (AI) and biotechnology introduces unprecedented capabilities alongside novel risks, further complicating the strategic calculus for states and international organizations. This confluence of factors suggests a departure from historical conflict paradigms, necessitating a comprehensive re-evaluation of future conflict scenarios.
This report aims to provide a rigorous, evidence-based analysis of the strategies and tactics employed by the world's nuclear-armed states. It delves into their current arsenals, evolving doctrines, and ongoing modernization programs to illuminate the state of global nuclear deterrence. Furthermore, the report undertakes a scientific assessment of the likelihood of a "Fourth World War," interpreting this concept not merely as a conventional military conflict but as a multi-domain, systemic collapse scenario driven by a combination of geopolitical, environmental, economic, and technological factors. The scope encompasses all nine recognized nuclear powers and examines the multifaceted drivers that could converge to precipitate a global-scale conflict in the 21st century.
The analysis presented herein integrates insights from strategic studies, geopolitical analysis, and futures research methodologies. The examination of nuclear strategies and arsenals draws upon established frameworks of deterrence theory, arms control, and military modernization, utilizing quantitative data and qualitative assessments of national security policies. The assessment of future conflict likelihood employs a multi-causal approach, recognizing that societal developments are shaped by complex interactions rather than linear progressions. This involves:
This comprehensive methodological approach ensures a robust, evidence-based discussion of complex global dynamics and their implications for future international security.
As of January 2024, nine states are recognized as possessing nuclear weapons: the United States, Russia, the United Kingdom, France, China, India, Pakistan, the Democratic People's Republic of Korea (North Korea), and Israel.3 The collective global inventory of nuclear weapons stood at approximately 12,405 warheads, with about 9,585 considered potentially operationally available.3
The distribution of these arsenals remains highly concentrated, with Russia and the United States together holding roughly 90% of all nuclear weapons. Their military stockpiles of usable warheads appeared relatively stable in 2024.3 However, a notable trend is the rapid expansion of China's nuclear arsenal, which saw a 20% increase from 500 to 600 warheads between 2024 and 2025.6 Projections suggest that China could potentially deploy as many intercontinental ballistic missiles (ICBMs) as either Russia or the United States by the end of the current decade.5
Beyond the major powers, India and Pakistan are also believed to be increasing the size of their nuclear arsenals in 2024.3 As of 2025, Pakistan is estimated to possess around 170 warheads, while India's stockpile is estimated at 180 warheads.7 North Korea, despite significant uncertainty surrounding its capabilities, is estimated to have assembled approximately 50 nuclear warheads, with sufficient fissile material for an additional 70 to 90.3 The United Kingdom's warhead stockpile is also projected to grow, with confirmed plans to raise the ceiling on warhead numbers to 260.3 France and Israel are reported to maintain relatively stable nuclear inventories.16
A significant shift is observable from a post-Cold War era of gradual disarmament to a renewed phase of re-armament and modernization. While the overall global nuclear inventory has seen a year-on-year decrease due to the dismantlement of retired warheads by the United States and Russia, the pace of these reductions is slowing. Simultaneously, the deployment of new nuclear weapons and the expansion of military stockpiles are accelerating across several nuclear-armed states.3 This indicates a critical reversal in global nuclear trends, where the focus is increasingly on enhancing operational capabilities rather than reducing overall numbers.
A major challenge looming on the horizon is the potential for an arms control vacuum. The bilateral 2010 New START Treaty between the United States and Russia is set to expire in February 2026. Without a new agreement to cap their respective stockpiles, the number of warheads deployed on strategic missiles by these two major nuclear powers is likely to increase.3 This impending lack of a binding arms control framework could further destabilize the global strategic environment and accelerate a broader arms race, as other nuclear states may follow suit.
Beyond mere quantitative increases, a qualitative shift in nuclear modernization programs is evident. Nuclear-armed states are heavily investing in upgrading existing weapons and developing newer versions designed for enhanced survivability, speed, and penetration. Examples include India's "canisterized" missiles, which can be transported with mated warheads and potentially deployed in peacetime, and China's development of hypersonic glide vehicles (HGVs) designed to evade radar detection and missile defenses.3 North Korea is also focusing on new solid-fuel missiles and various hypersonic weapons.17 These technological advancements are not just about increasing destructive power but about making nuclear weapons potentially more "usable" in a conflict scenario, thereby raising concerns about a lowered threshold for their employment.
Table 2.1: Estimated Global Nuclear Warhead Inventories (January 2025)
| Country | Total Inventory (Jan 2025) | Military Stockpile (Jan 2025) | Deployed Strategic (Jan 2025) | Key Modernization Efforts |
|---|---|---|---|---|
| United States | 5,177 16 | 3,700 16 | 1,670 16 | Sentinel ICBM, Columbia-class SSBN 8 |
Note: Data for deployed strategic warheads for China, India, Pakistan, North Korea, and Israel are subject to higher uncertainty due to varying levels of transparency and different storage/deployment postures. Numbers may fluctuate based on new assessments.
The United States maintains a nuclear doctrine of "flexible response," which allows for the consideration of nuclear weapons use in "extreme circumstances" to defend its vital interests or those of its allies and partners.30 This doctrine extends beyond deterring solely nuclear attacks, potentially encompassing "significant non-nuclear attacks," such as major cyberattacks on critical infrastructure or command and control systems, as a valid reason for nuclear use.30 This broadened definition of triggers for nuclear use carries implications for escalation management. By expanding the scope of deterrence to include non-nuclear threats, the United States introduces a potential for miscalculation in conventional or cyber conflicts, where an adversary might underestimate the risk of a nuclear response. This expansion could inadvertently lower the threshold for nuclear escalation by blurring the traditional lines between conventional and nuclear warfare.
The United States relies on a robust nuclear triad for delivery systems, comprising land-based Intercontinental Ballistic Missiles (ICBMs), specifically the LGM-30G Minuteman III, housed in hardened silos across multiple states.32 The sea-based leg consists of Submarine-Launched Ballistic Missiles (SLBMs) deployed on Ohio-class submarines, which serve as an undetectable and survivable second-strike capability.32 The air component includes strategic bombers such as the B-52H Stratofortress and the B-2A Spirit, offering flexible conventional and nuclear response options.32 This diversified triad ensures that a devastating retaliatory strike remains possible even if one or two components are neutralized in a first strike.32
Nuclear command and control (NC2) in the United States is highly centralized, with the President holding sole authority to authorize the use of nuclear weapons.35 This decision is communicated through an intricate Nuclear Command and Control System (NCCS), which provides the President with situational awareness, advance warning, and the means to prevent unauthorized or accidental use.35 The system is designed to ensure crisis stability and maintain the safety and effectiveness of the deterrent.35
The United States is currently engaged in a comprehensive nuclear modernization program, projected to cost approximately $1.7 trillion over 30 years.19 This ambitious program aims to replace and refurbish aging systems developed in the 1970s and 1980s, including the development of new platforms like the Sentinel ICBM and Columbia-class SSBNs.8 While essential for maintaining a credible deterrent, this modernization effort faces planning and funding challenges.3 Furthermore, the push for increasing warhead numbers, partly influenced by China's expanding nuclear deployments, underscores a competitive dynamic that could undermine future arms control agreements and further destabilize the global nuclear landscape.3 The ongoing qualitative and quantitative enhancements by major nuclear powers, including the United States, contribute to a new arms race that could increase the risk of conflict.
Russia's nuclear doctrine underwent a significant shift in 1993, when it abandoned its no-first-use pledge, a policy adopted by the Soviet Union in 1982.38 The 2024 version of its nuclear doctrine, titled "Basic Principles of State Policy on Nuclear Deterrence," is widely recognized for lowering the threshold for nuclear weapons use, even compared to its previous iteration.39 This doctrine explicitly states that nuclear weapons can be used first in response to conventional aggression that poses a "critical threat to their sovereignty and/or territorial integrity".39 This represents a deliberate and aggressive shift in Russia's nuclear posture, making nuclear escalation a more immediate concern in conventional conflicts, particularly in the European theater. The doctrine, combined with Russia's frequent use of nuclear threats, serves as a tool for political coercion, aiming to force concessions from adversaries by raising the specter of nuclear use.
Russia possesses the world's largest nuclear arsenal, with a significant portion of its strategic forces based on a triad of delivery vehicles.7 This triad includes land-based ICBMs, such as the SS-X-29 (Sarmat) heavy ICBM and the SS-27 Mod 2 (Yars) ICBM, which carry the majority of Russia's strategic nuclear warheads.20 The sea-based component consists of ballistic-missile submarines (SSBNs) like the Dolgorukiy (Borei) class, and the air component involves strategic bombers.20
Russia's nuclear command and control (NC2) system is centered around the automatic system known as Kazbek, with a "nuclear briefcase" (Cheget) held by the head of state, the Minister of Defense, and the head of the General Staff.40 It is believed that affirmations from at least two of these three individuals are required to trigger an actual launch.40 The Strategic Rocket Forces (RVSN RF) are a separate combat arm responsible for controlling Russia's land-based ICBMs.41
Russia is in the process of concluding a comprehensive modernization of its strategic nuclear forces.20 However, its program faced challenges in 2024, including a test failure and further delays in the development of the new Sarmat ICBM and slower than expected upgrades of other systems.3 Despite these setbacks, Russian deployments of nuclear weapons are expected to rise in the coming years, driven by the modernization of strategic forces to carry more warheads per missile and the reloading of previously emptied silos.3
A significant concern arises from the strategic ambiguity inherent in Russia's nuclear posture. While a public doctrine exists, statements by Russian officials and generals frequently go beyond the published text, implying an even lower threshold for preemptive or preventive nuclear strikes.39 This deliberate vagueness contributes to strategic uncertainty, increasing the risk of miscalculation by adversaries who may misinterpret Russian intentions or perceived "red lines." Such ambiguity can lead to an unintended escalation of conflicts, as the precise conditions for nuclear use become less clear, potentially provoking responses that could spiral out of control.42
The United Kingdom adheres to a policy of "minimum credible nuclear deterrence," which is primarily delivered through "continuous at-sea deterrence" (CASD).21 The UK does not maintain a no-first-use policy 44 and deliberately maintains ambiguity regarding the precise circumstances, methods, and scale of nuclear weapons use.43 The doctrine stipulates that nuclear weapons would only be considered for use in "extreme circumstances of self-defence," which explicitly includes the defense of its NATO allies.43 This approach is designed to preserve peace, prevent coercion, and deter aggression by ensuring potential aggressors understand that the costs of attacking the UK or its allies would far outweigh any benefits.43
The UK's nuclear deterrent is exclusively sea-based, consisting of four Vanguard-class nuclear-powered ballistic missile submarines (SSBNs).14 Each submarine is capable of carrying Trident II D-5 ballistic missiles, which can deliver thermonuclear warheads from multiple independently targetable re-entry vehicles (MIRVs).21 A key operational principle is that at least one submarine is always on patrol, submerged and undetected, ensuring a continuous and survivable deterrent.21 These submarines are typically at several days' notice to fire, and since 1994, the UK does not target its missiles at any specific state.43
In terms of command and control, the authority to authorize a nuclear strike rests solely with the Prime Minister.21 Orders would likely be issued from the Pindar command bunker in central London and relayed through a secure chain of command to the submarine commander.21
The UK is undertaking a significant modernization of its nuclear forces, with plans to replace the existing Vanguard-class submarines with the new Dreadnought-class submarines, expected to enter service starting in 2031.21 Furthermore, the cap on the UK's nuclear stockpile is set to increase to no more than 260 warheads, a reversal of previous disarmament commitments.3 This decision, alongside the policy of no longer disclosing the exact number of deployed missiles, indicates a departure from earlier efforts to reduce nuclear arsenals. This stance, while intended to enhance deterrence and ensure national security, carries the risk of undermining global non-proliferation norms. By signaling a greater reliance on nuclear weapons for its security, the UK's policy could inadvertently encourage other non-nuclear states to pursue their own nuclear capabilities, thereby contributing to a broader and more dangerous arms race.47 This tension between national deterrence and international non-proliferation is a critical aspect of the evolving nuclear landscape.
France's nuclear doctrine is fundamentally defensive, built upon the concept of "deterrence by punishment".48 Its primary objective is to protect the country's "vital interests" and safeguard its sovereignty and freedom of action.48 The precise scope of these "vital interests" is intentionally kept vague, a deliberate ambiguity designed to enhance deterrence by complicating an adversary's calculations.50 Ultimately, the President of France holds the sole prerogative to define what constitutes these vital interests in any given situation.50
Following the end of the Cold War, France decommissioned its land-based nuclear missiles, transitioning to an arsenal composed solely of air- and sea-based components.49 This includes the development of third-generation nuclear-powered ballistic missile submarines (SSBNs) and new air-launched cruise missiles.3
The President of France possesses the sole authority to order a nuclear strike.49 This decision-making process is supported by the Jupiter Command Post, a secure facility located in the bunker of the Élysée Palace, equipped with advanced communication and protection systems to enable crisis management and contact with military command posts and foreign governments.49
France continued its modernization programs in 2024, focusing on developing a third-generation SSBN and a new air-launched cruise missile, as well as refurbishing and upgrading existing systems.3
A notable aspect of France's nuclear posture is the strategic ambiguity surrounding its "vital interests" and their potential European dimension. While this ambiguity is intended to enhance deterrence, President Emmanuel Macron's recent emphasis on the "European dimension" of French vital interests suggests a potential expansion of its nuclear umbrella.48 This raises critical questions about the conditions under which France might extend its nuclear protection to other European nations, potentially drawing it into broader European conflicts and complicating NATO's collective security framework. The implied extension of nuclear guarantees beyond national borders could lead to complex discussions about burden-sharing, decision-making authority, and the potential for inadvertent escalation within a wider European conflict, particularly given the ongoing geopolitical tensions in the region.
China maintains a long-standing "no-first-use" (NFU) policy, a pledge adopted in 1964, stating that it will never be the first to use nuclear weapons under any circumstances.53 The core of its nuclear strategy centers on deterrence through "assured retaliation," meaning it aims to survive a theoretical first strike and retaliate proportionately.53 This approach is intended to demonstrate the purely self-defensive nature of China's nuclear strategy and to maintain strategic stability, particularly in the Asia-Pacific region.56
China operates a nuclear triad, consisting of land-based ballistic missiles, submarine-launched ballistic missiles (SLBMs), and air-launched ballistic missiles.54 Its arsenal includes Dongfeng intermediate and intercontinental ballistic missiles, Julang-3 SLBMs on Type 094 submarines, and air-launched ballistic missiles on Xi'an H-6N bombers.54 China is rapidly expanding its ICBM silo fields, indicating a significant increase in its land-based strategic capabilities.22
Information regarding the exact number of China's nuclear warheads is a state secret.54 Unlike the United States and Russia, nearly all Chinese warheads are believed to be stored separately from their delivery systems.54 The nuclear command and control structure typically involves a Joint Operations Command Center in Beijing, with theater-level and service command posts below.57
China's nuclear arsenal is undergoing rapid modernization and expansion. Between 2024 and 2025, its arsenal saw a 20% increase from 500 to 600 warheads.6 This quantitative growth is accompanied by significant qualitative improvements in its delivery systems, including the deployment of hypersonic glide vehicles (HGVs) designed to evade radar detection and missile defenses.6 Furthermore, some of China's nuclear forces are reported to have moved toward a "Launch on Warning" (LOW) posture in the early 2020s.54
The coexistence of China's long-standing No-First-Use (NFU) policy with its rapid nuclear arsenal expansion and reported move towards a "Launch on Warning" (LOW) posture presents a significant strategic tension. While NFU is designed to reassure other states that China will not initiate nuclear conflict, a LOW posture implies a readiness to launch upon detecting an incoming attack. This creates a "credibility paradox": the operational shift towards a more rapid response posture, even if intended for assured retaliation, could be misinterpreted by adversaries, potentially increasing the risk of accidental or inadvertent escalation due to false alarms or misinterpretation of signals.55 This dynamic introduces a layer of uncertainty into strategic stability, as it blurs the precise conditions for nuclear use.
China's comprehensive nuclear arms buildup is characterized by both a rapid quantitative increase in its warhead count and substantial qualitative improvements in its delivery systems. The significant increase in its nuclear stockpile, coupled with the deployment of advanced capabilities like hypersonic glide vehicles and the construction of numerous new ICBM silos, demonstrates a strategic commitment to a robust and technologically advanced nuclear force.6 This dual-pronged approach aims to enhance China's deterrence capabilities and potentially challenge the nuclear parity of the United States and Russia, contributing to a broader global arms race.
India's nuclear doctrine is founded on the principles of "credible minimum deterrence" (CMD) and a "no first use" (NFU) policy.23 This doctrine asserts that nuclear weapons are solely for deterrence purposes and would only be used in retaliation against a nuclear attack on Indian territory or on Indian forces anywhere.58 India's NFU policy, however, is qualified; while it pledges not to use nuclear weapons against non-nuclear weapon states, it does not extend this commitment to nuclear-armed adversaries.23 This nuance is crucial for understanding its deterrence posture, particularly in the context of its contentious relationships with nuclear-armed Pakistan and rapidly modernizing China. This qualification implies a potential for first use against nuclear adversaries if deterrence fails, adding complexity to regional strategic stability.
India is actively developing a nuclear triad capability, encompassing land-based ballistic missiles, air-delivered nuclear weapons, and submarine-launched ballistic missiles (SLBMs).23 Its land-based missile force includes the Agni series, with ranges up to 5,000-5,500 kilometers for the Agni-V.24 Air-delivered nuclear weapons are primarily carried by fighter jets such as the Dassault Rafale and Sukhoi Su-30.24 The sea-based component is spearheaded by the Arihant-class submarines, which are capable of launching SLBMs.23
India's nuclear arsenal is under strict civilian control through the Nuclear Command Authority (NCA).24 The NCA comprises a Political Council, chaired by the Prime Minister, which holds the exclusive authority to approve a nuclear strike. An Executive Council, chaired by the National Security Advisor, provides technical and strategic advice and executes the Political Council's orders.24 The Strategic Forces Command (SFC) is responsible for the operational management of India's nuclear arsenal, ensuring the readiness, safety, and security of its weapons and delivery systems.61 This structure emphasizes civilian supremacy and a multi-tiered decision-making process to prevent accidental or unauthorized use.61
India has continued to expand its nuclear arsenal and develop new types of nuclear delivery systems in 2024, including "canisterized" missiles that may be capable of carrying nuclear warheads during peacetime.3 This ongoing development appears to be a reactive response to the nuclear capabilities and modernization efforts of China and Pakistan. Historical evidence suggests that Chinese nuclear testing and Pakistan's acquisition of nuclear capability have consistently pushed the development of India's nuclear program to its next stage.60 This reactive dynamic contributes to a regional arms race, increasing the overall risk of conflict in South Asia, as each country's advancements are perceived as threats by the others, leading to a self-perpetuating cycle of armament.
Pakistan's nuclear doctrine is termed "Full Spectrum Deterrence" (FSD), a military strategy designed to promote deterrence by guaranteeing an immediate "massive retaliation" to an aggressive attack.25 Unlike India, Pakistan does not adhere to a no-first-use policy and explicitly reserves the right to use nuclear weapons first, particularly if its existence is threatened.25 FSD aims to deter threats across the entire conflict spectrum, from conventional to sub-conventional, utilizing both strategic and tactical nuclear signaling.25 This doctrine is fundamentally geared towards preventing India from any military intervention that could lead to the disintegration of Pakistan, as occurred in 1971.63
Pakistan has developed a diverse range of nuclear delivery systems. Its land-based missile systems include the Shaheen I and II, Ghauri, and the recently tested Ababeel missile, which is reported to be capable of carrying Multiple Independently Targetable Reentry Vehicles (MIRVs).26 Air-based delivery systems include F-16s and Mirage aircraft, which have been modified to carry Ra'ad air-launched cruise missiles (ALCMs) and free-fall nuclear bombs.26 Notably, Pakistan employs short-range Nasr (Hatf-IX) missiles as tactical nuclear weapons, intended for battlefield use.25
Pakistan's nuclear arsenal is controlled by the National Command Authority (NCA), which is chaired by the Prime Minister and holds the sole authority to authorize the use of nuclear weapons.26
In 2024, Pakistan continued to develop new delivery systems and accumulate fissile material, indicating a likely expansion of its nuclear arsenal over the coming decade.3
A significant risk of escalation stems from Pakistan's Full Spectrum Deterrence (FSD) doctrine, which deliberately blurs the lines between conventional and nuclear thresholds. Its explicit first-use policy is designed to compensate for India's conventional military superiority. This strategy, while intended to deter, significantly increases the risk of nuclear escalation in a conventional conflict, as India might misinterpret Pakistan's "red lines" or perceived threats.25 The ambiguity surrounding nuclear thresholds, as observed in the stability-instability paradox, can lead to higher-intensity conventional conflicts, increasing the probability of unintended nuclear use.42
Furthermore, FSD is characterized as a "strategy of perception" and "psychology, not arithmetic," with the aim of "paralysing Indian decision-making by making any retaliation appear potentially escalatory".25 This highlights a sophisticated psychological component to Pakistan's deterrence, where the perceived risk of nuclear use is manipulated to achieve strategic objectives. This approach relies heavily on shaping the adversary's perceptions and decision-making processes through the threat of escalation, rather than solely on military capability.
North Korea adopted a nuclear preemption doctrine in September 2022, asserting its right to initiate war with nuclear weapons.65 This doctrine states that nuclear weapons can be used if a non-nuclear attack is judged to be "drawing near" or "imminent," even if it has not yet materialized.65 This is a more aggressive stance than Russia's "first use" policy, as it allows for a nuclear strike to commence a conflict.65 The stated purpose of North Korea's military force extends beyond mere deterrence to include coercion and intimidation.65
North Korea has developed a highly diverse missile force, encompassing short-range tactical missiles, sea-based missiles, and new launch platforms such as silo-based and underwater capabilities.27 It is actively developing solid-fuel missile technology and various hypersonic weapons, which are designed to improve the quality and survivability of its nuclear and missile capabilities.17
North Korea's nuclear forces operate under the "monolithic command of the president of the State Affairs," Kim Jong Un, who possesses "all decisive powers" regarding nuclear weapons.66 Its nuclear command and control (NC2) system is characterized as "automatic," allowing for immediate nuclear strikes based on pre-determined operational plans if Kim is eliminated or incapacitated.66 This structure prioritizes rapid execution and Kim's decision-making primacy. Furthermore, North Korea employs information manipulation and narrative control as part of its "nuclear-cognitive warfare" strategy to influence adversary decision-making.67
North Korea continues to modernize and grow its nuclear arsenal, with Kim Jong Un inspecting a "nuclear material production base" in September 2024 and January 2025.17 South Korean officials warned in July 2024 that North Korea was in the "final stages" of developing a "tactical nuclear weapon".3
The nuclear preemption doctrine adopted by North Korea is highly aggressive, permitting it to initiate war with nuclear weapons if an attack is merely "imminent," even before it materializes. This doctrine is strategically coupled with a "nuclear-cognitive warfare" approach that utilizes disinformation, narrative control, and psychological operations. The aim is to instill fear, despair, and helplessness among the South Korean public and to disrupt and dismantle military command structures, thereby undermining the cohesion of the ROK-US alliance.67 This represents a unique and highly destabilizing approach to nuclear strategy, moving beyond traditional deterrence to actively manipulate the adversary's cognitive processes.
The accelerated development and pursuit of tactical nuclear weapons by North Korea are intended to provide options for nuclear use below the strategic level.3 This development, combined with its preemption doctrine, significantly lowers the potential threshold for nuclear use in a regional conflict. The proliferation of such "usable" nuclear weapons increases the risk of limited nuclear exchanges, as North Korea seeks to gain strategic advantage through intimidation and the threat of immediate nuclear action in a regional context.27
Israel's nuclear doctrine is widely known as the "Samson Option," a deterrence strategy that involves the potential for massive retaliation with nuclear weapons as a "last resort" against an existential threat to the state.68 This doctrine is intrinsically linked with Israel's long-standing policy of "nuclear opacity" or "deliberate ambiguity," whereby it consistently refuses to officially confirm or deny its possession of nuclear weapons or describe how they would be used.16 This policy is designed to influence other governments' perceptions, strategies, and actions without definitive public statements, thereby enhancing deterrence by keeping potential responses uncertain and potentially catastrophic.
Israel is believed to possess a nuclear triad of delivery options, enabling it to launch nuclear weapons from land, sea, and air.28 This includes F-15 and F-16 fighter jets, Dolphin-class submarine-launched cruise missiles, and the Jericho series of intermediate to intercontinental range ballistic missiles.28 The Jericho III ICBM is estimated to have a range of up to 11,500 km, providing a significant long-range strike capability.29
Due to its policy of deliberate ambiguity, little public information is available on Israel's nuclear command and control (NC2) structure. However, it is understood that the Israel Defense Forces (IDF) present assessments to the political echelon for major operations, suggesting a centralized decision-making process for critical military actions.71
Israel is believed to be actively modernizing its nuclear arsenal.3 In 2024, it conducted a test of a missile propulsion system that could be related to its Jericho family of nuclear-capable ballistic missiles.3
Israel's deliberate policy of nuclear ambiguity, combined with the "Samson Option," serves as a core element of its deterrence strategy. By refusing to explicitly confirm or deny its nuclear capabilities, Israel aims to influence adversaries' perceptions and actions without definitive public statements. This approach enhances deterrence by maintaining uncertainty about the nature and scale of its potential response, which could be catastrophic, thereby discouraging aggression.68 This strategy effectively leverages the psychological impact of an unknown but potentially devastating retaliatory capability.
Furthermore, Israel's "Begin Doctrine" incorporates a proactive military counter-proliferation strategy, including preventive strikes against regional actors seeking to acquire nuclear weapons.70 This doctrine has been demonstrated through historical operations, such as the destruction of pre-critical Iraqi and Syrian nuclear reactors in 1981 and 2007, respectively.70 In 2025, Israel also extensively targeted the Iranian nuclear program using malware, assassinations, and airstrikes during their conflict.70 This proactive approach reflects a commitment to preventing nuclear proliferation in the region through direct military action, rather than relying solely on deterrence or international non-proliferation regimes.
The concept of a "Fourth World War" extends beyond the traditional understanding of large-scale conventional military conflicts that characterized the first two global wars. While the term "Fourth Reich" has been used in academic literature to refer to a hypothetical resurgence of Nazi influence 72, and "Fourth World nations" describe marginalized indigenous tribes unaffected by global events 73, the contemporary interpretation of a "Fourth World War" in strategic discourse often refers to a multi-domain, systemic global crisis. This type of conflict would involve a convergence of various non-traditional and traditional threats, leading to widespread societal collapse or existential risks to human civilization.1
Historically, World War I and II were defined by large-scale military engagements between state actors, involving massive casualties and global reach. However, the 21st century introduces new dimensions of conflict. The "Fourth World War" could manifest not as a single, declared war, but as a series of interconnected crises across geopolitical, environmental, economic, and technological domains. This perspective is informed by the understanding that modern conflicts are increasingly complex, involving a multiplicity of drivers and non-state actors.74 The "Fourth World War" would represent a breakdown of global systems and institutions, where the cumulative impact of various stressors leads to widespread instability, resource wars, and potentially, existential threats to humanity. It is a scenario where the "war" is fought on multiple fronts simultaneously, against a backdrop of accelerating change and diminishing global resilience.
The global geopolitical landscape in the 2020s has witnessed a significant return to Cold War levels of risk.76 This heightened tension is characterized by ongoing major wars in Europe (e.g., Russia-Ukraine conflict) and the Middle East (e.g., Israel-Hamas conflict), which continue to fuel regional instability and have broader impacts on energy and food security.76 The increasing number, intensity, and length of local and civil wars further contribute to this volatile environment.77
The return of great-power competition, particularly between the United States, Russia, and China, has amplified the risks of conflict, including the potential for nuclear escalation.80 This competition is driven by shifting global economic power, with the Asia-Pacific region anticipated to be a key long-term growth engine. The pursuit of advanced technology in warfare and the desire to gain competitive advantage act as structural catalysts for security dilemmas among these powers.83
The current environment presents a fertile ground for miscalculation and unintended escalation. Decision-makers may struggle to identify adversary thresholds, and delays in recognizing the onset of a crisis can impede the transmission of coercive signals.80 The boundaries of "red lines" become fluid as conflicts evolve, increasing the prospect of inadvertent escalation.80 For instance, nuclear threats, while intended to increase adversary fears, may not always compel substantial changes in behavior, especially when an inferior nuclear power antagonizes a more powerful rival.80 The reorganization of decision-making bodies can also alter access to or interpretation of information, complicating efforts to influence power centers.80
The rise of nationalism and protectionism further exacerbates these dynamics, leading to increased scrutiny of globalization's positive impacts and exposing weaknesses in global supply chains. Governments are increasingly tying trade measures to economic security and climate goals, while expanding tariffs, subsidies, and industrial policies, which could trigger retaliatory measures and add trade barriers. This fragmentation of global trade and the pursuit of national interests over collective stability contribute to a more fractious and uncertain international system. The struggle for control over critical resources, such as rare earth metals, also fuels geopolitical competition, as countries implement strategies to secure access to essential minerals for high-tech manufacturing. This complex web of economic, political, and military competition, coupled with a lack of consensus on international norms and institutions, increases the overall likelihood of major global conflict in the 21st century.82
Climate change and resource scarcity are not direct causes of war but function as powerful conflict multipliers, exacerbating existing vulnerabilities and creating new pathways for instability. Global temperatures are projected to remain at or near record levels in the coming five years, with an 80% chance that at least one year between 2025 and 2029 will be warmer than the warmest year on record (currently 2024). Projections indicate an 86% chance that at least one year will exceed 1.5°C above pre-industrial levels, and a 70% chance that the five-year average warming for 2025-2029 will surpass 1.5°C. Every additional fraction of a degree of warming drives more harmful heatwaves, extreme rainfall events, intense droughts, and rising sea levels.
The impacts on critical resources are severe. Global water demand is projected to increase by 20% to 25% by 2050, with an additional 1 billion people expected to live with extremely high water stress, even under optimistic temperature rise scenarios. For regions like the Middle East and North Africa, this means 100% of the population will live with extremely high water stress by 2050, posing a direct threat to political stability. Furthermore, without adaptation, some regions could see a decline in crop yields of more than 10% over the next five to 25 years. Feeding a projected 10 billion people by 2050 will require producing 56% more food calories than in 2010, all while dealing with increasing water stress and climate-driven disasters.
This intensifying resource stress and environmental degradation lead to several destabilizing social effects. Lower agricultural production, economic stagnation or decline, and mass migrations from areas of scarcity to perceived opportunities are all potential consequences.86 These pressures can weaken governing institutions and inflame intergroup inequalities, making violent conflict more likely.86 Scientific assessments suggest that climate variability and change have influenced between 3% and 20% of conflict risk over the last century, and this influence is expected to increase substantially with intensifying climate change.87 The mechanisms involve economic shocks to agricultural communities, which heighten the risk of armed conflict when combined with other drivers of violence.88
The overwhelming scientific consensus indicates that human emissions of greenhouse gases are the primary driver of these unusual changes, which are already having significant adverse impacts on human well-being and ecosystems. Unless emissions are greatly reduced, this harm will continue to grow, leading to unprecedented conditions that societies may struggle to adapt to.88 The inability of existing systems and models to cope with these growing challenges is likely to produce greater contestation at every level, increasing the risk of conflict.84
The global economy is undergoing profound transformations driven by rapid technological advancements, particularly in artificial intelligence (AI) and automation. AI is projected to affect almost 40% of jobs worldwide, with potential for significant job displacement, especially in white-collar occupations. While AI is expected to unlock substantial economic value, potentially reaching $15.7 trillion by 2030, this shift is not without its challenges. The economic benefits may not be widely shared, potentially deepening inequality and leading to social fragmentation. This imbalance can create economic insecurity and declining social trust, destabilizing societies worldwide.
The increasing rates of "job churn" due to AI and automation mean that individuals may work for many different organizations in a short span, potentially jeopardizing their financial futures if not adequately supported by policy changes. The transition to an AI-driven economy requires workers to develop new skills and adapt to AI-driven workflows, posing a challenge for those with low levels of education or in vulnerable positions. If not managed effectively, this economic disruption could lead to a decline in overall welfare even as GDP increases.
Compounding these economic pressures are significant demographic challenges. South Korea, for instance, faces an unprecedented demographic crisis characterized by a historically low birth rate (0.72 children per woman in 2023, projected to drop further) and a rapidly aging population. This leads to a gradual decline in the total population and jeopardizes the country's economic model by reducing the working-age population and increasing the dependency ratio. Factors contributing to this crisis include the high cost of education and housing, a highly competitive work culture, poor work-life balance, and the disproportionate burden of domestic chores on women. Such severe demographic shifts can undermine societal cohesion and economic stability, creating internal pressures that could spill over into regional or global conflicts.
The digital domain also presents growing risks. Cyberattacks are becoming more frequent and severe, with annual cybercrime damage projected to reach $10.5 trillion by 2025. These threats target financial networks, communication channels, and critical infrastructure, posing significant national security concerns.90 The increasing complexity of cyberattacks, including AI-driven malware and zero-day attacks, demands forward-thinking strategies and robust defenses. The potential for cyberattacks to disrupt critical systems further contributes to the fragility of societies already grappling with economic and social instability.
The accelerating pace of technological innovation, particularly in artificial intelligence (AI), robotics, and biotechnology, introduces new and complex risks that could profoundly reshape future conflict dynamics. Major AI breakthroughs are rapidly transforming various fields, with AI research undergoing significant changes in topics, methods, and community. Topics like AI ethics and safety, and AI for social good, have become central themes in major AI conferences.
A hypothetical but widely discussed future scenario is the "technological singularity," a point at which technological growth becomes uncontrollable and irreversible, with AI potentially surpassing human intelligence. While some envision AI enhancing human capabilities and addressing societal challenges, others express concern over the risks associated with extreme reliance on AI. Skeptics question the feasibility of true machine intelligence replicating human cognitive abilities, but warnings persist about self-aware robots taking over daily lives or even posing existential threats to humanity.
The increasing integration of AI into military systems, even outside direct nuclear weapon systems, has the potential to influence nuclear escalation. AI-powered decision-support systems may compress decision-making timelines, potentially increasing miscalculation risks during a crisis.2 Opaque recommendations from AI systems could bias human decision-makers towards acting, while autonomy in systems with counterforce potential may undermine strategic stability by threatening the integrity of second-strike capabilities.2 This raises fundamental questions about whether AI introduces new risks, exacerbates existing ones, or fundamentally alters the nature of nuclear escalation.2 No serious proposal has emerged to entrust computers or AI with the actual decision to launch nuclear weapons, but the potential for AI to enhance human control over nuclear weapons in appropriate contexts is being explored.91
Biotechnology, particularly gene editing technologies like CRISPR and synthetic biology, has seen remarkable advancements in the last two decades. These fields offer immense potential for medical breakthroughs, such as next-generation therapies and correcting genetic disorders, and for environmental sustainability, like engineering organisms to break down plastics or absorb carbon dioxide. However, these advancements also present significant ethical dilemmas and dual-use concerns. Issues such as data privacy and consent, algorithmic bias in AI systems (leading to inequitable outcomes), accountability and transparency of AI decisions, and the potential for misuse of powerful biotechnologies are critical challenges. The ability to engineer life with precision raises profound questions about human intervention limits and the equitable distribution of benefits, requiring robust ethical frameworks and global governance solutions. The convergence of these disciplines, with AI accelerating biological design, means that the pace of change is rapid, and the potential for unforeseen consequences, including those that could contribute to global instability, is high.
The preceding analysis reveals a confluence of escalating risk factors that, when considered collectively, suggest a non-negligible, albeit complex, likelihood of a systemic global conflict, conceptualized as a "Fourth World War." This is not merely a prediction of a conventional military confrontation but a recognition of the increasing fragility of global systems under mounting pressure from multiple, interconnected domains.
The primary drivers of this elevated risk are:
These factors are not isolated but are deeply interdependent. For instance, climate-induced resource scarcity can intensify geopolitical competition over remaining resources. Economic disruptions can exacerbate social inequalities, leading to internal instability that external actors might exploit. The rapid development of AI could further supercharge military capabilities, while simultaneously increasing the speed and scale at which wars can be fought, potentially making escalation harder to control. The interplay of these elements creates a complex adaptive system where small perturbations can have cascading, unpredictable effects across global domains.
The pathways to a "Fourth World War" are multifaceted and could arise from various escalation scenarios, often involving a combination of the risk factors identified. While direct, large-scale conventional warfare between major powers remains a possibility, the more probable pathways involve:
These scenarios are not mutually exclusive and could interact in complex, unpredictable ways. A regional resource conflict, for example, could escalate rapidly if major powers with opposing interests and advanced military technologies become involved, potentially leading to a nuclear close call or even limited nuclear exchange. The increasing interconnectedness of global systems means that a crisis in one domain can quickly cascade into others, amplifying overall instability.
While the prospect of a "Fourth World War" is concerning, it is not an immutable outcome. Strategic interventions and proactive measures can significantly reduce the likelihood and severity of negative developments. Addressing these complex, interlinked threats requires a multi-pronged approach focused on strengthening international cooperation, enhancing arms control, promoting sustainable development, and ensuring responsible technological governance.
Key areas for mitigation and resilience-building include:
These measures, while challenging to implement in a polarized world, represent pathways to steer global trajectories away from catastrophic conflict. The collective will of nations and the proactive engagement of all stakeholders are necessary to navigate this perilous period and build a more stable, equitable, and sustainable future.
The analysis presented in this report underscores a critical juncture in global security. The strategies and tactics of nuclear-armed states are evolving towards more assertive postures, driven by modernization programs that enhance both the quantity and quality of their arsenals. The erosion of arms control frameworks, coupled with the development of more "usable" nuclear weapons and ambiguous doctrines, significantly elevates the risk of nuclear escalation in regional and global conflicts. This traditional military threat is compounded by a complex web of non-traditional challenges: intensifying geopolitical rivalries, the accelerating impacts of climate change and resource scarcity, profound economic disruptions driven by technological shifts, and the unforeseen risks posed by emerging technologies like AI and advanced biotechnology.
The concept of a "Fourth World War" in this context is not a singular, conventional military event, but a plausible scenario of systemic global collapse resulting from the convergence and interaction of these multifaceted stressors. The interdependencies between these risk factors mean that a crisis in one domain can rapidly cascade into others, amplifying instability and making de-escalation increasingly difficult. The potential for miscalculation, unintended escalation, and the erosion of societal resilience are heightened in this complex environment.
To mitigate these escalating risks and foster a more secure future, the following conclusions and recommendations are put forth:
The prospect of a "Fourth World War" is a stark reminder that global security is indivisible and profoundly interconnected. Averting such a catastrophic future requires a concerted, multi-dimensional effort from all state and non-state actors, prioritizing long-term strategic stability and human well-being over short-term gains and narrow national interests. The scientific evidence points to clear risks, but also to pathways for collective action to build a more resilient and peaceful world.