What Happened to Nuclear War?
The threat of nuclear war, once a defining feature of the Cold War, has seen a significant resurgence in the 2020s due to escalating geopolitical tensions, the erosion of arms control treaties, and the modernization and expansion of nuclear arsenals by multiple states. As of April 2026, global experts warn of an unprecedented risk of nuclear catastrophe, with the Doomsday Clock set to its closest point ever to midnight.
Quick Answer
As of April 2026, the threat of nuclear war is considered to be at an unprecedented high, with the Doomsday Clock set to 85 seconds to midnight. This heightened risk is driven by the expiration of key arms control treaties like New START, the expansion and modernization of nuclear arsenals by several nations including China, Russia, and North Korea, and ongoing geopolitical conflicts. Efforts to prevent proliferation are under significant strain, and new dialogues are attempting to address the complex, multi-actor nuclear environment.
📊Key Facts
📅Complete Timeline14 events
Atomic Bombing of Hiroshima
The United States drops the 'Little Boy' atomic bomb on Hiroshima, Japan, marking the first use of a nuclear weapon in warfare.
Soviet Union Develops Nuclear Weapons
The Soviet Union successfully tests its first atomic bomb, initiating the nuclear arms race and the Cold War.
Cuban Missile Crisis
A 13-day confrontation between the United States and the Soviet Union over Soviet ballistic missile deployment in Cuba, bringing the world to the brink of nuclear war.
Nuclear Non-Proliferation Treaty (NPT) Signed
The NPT is opened for signature, aiming to prevent the spread of nuclear weapons, promote disarmament, and foster peaceful uses of nuclear energy. It entered into force in 1970.
Intermediate-Range Nuclear Forces (INF) Treaty Signed
The US and USSR sign a treaty to eliminate ground-launched ballistic and cruise missiles with ranges between 500 and 5,500 kilometers.
START I Treaty Signed
The US and USSR sign the Strategic Arms Reduction Treaty, aiming to cut their strategic nuclear arsenals by a third.
North Korea Conducts First Nuclear Test
North Korea claims to have successfully tested its first nuclear weapon, significantly escalating proliferation concerns.
Treaty on the Prohibition of Nuclear Weapons (TPNW) Enters into Force
The TPNW becomes international law, prohibiting the development, testing, production, stockpiling, stationing, transfer, use, and threat of use of nuclear weapons.
North Korea Declares Itself a Nuclear Weapons State
North Korean state media reports the passage of a new law declaring the country a nuclear weapons state, with Kim Jong Un vowing never to give up its nuclear weapons.
Israeli Strikes Risk Driving Iran Toward Nuclear Weapons
Israeli strikes on Iran are reported to risk pushing Tehran closer to developing nuclear weapons, amidst ongoing tensions.
Doomsday Clock Set to 85 Seconds to Midnight
The Bulletin of the Atomic Scientists moves the Doomsday Clock to 85 seconds to midnight, the closest it has ever been, citing nuclear risks, climate change, and AI.
New START Treaty Expires
The New Strategic Arms Reduction Treaty, the last bilateral nuclear arms control agreement between the US and Russia, expires without a successor, leading to an era of potentially unconstrained nuclear build-up.
Global Nuclear Arsenals Continue to Grow
The Nuclear Weapons Ban Monitor 2026 reports that the number of nuclear warheads available for use by the nine nuclear-armed states has increased for the ninth consecutive year in 2025, reaching 9,745.
North Korea Seeks Nuclear Recognition for US Talks
North Korean leader Kim Jong Un states that any bilateral talks with the United States would require Washington to recognize North Korea as a nuclear-armed state, further solidifying its nuclear posture.
🔍Deep Dive Analysis
The concept of nuclear war emerged with the development of atomic weapons during World War II, culminating in the atomic bombings of Hiroshima and Nagasaki in August 1945, which remain the only wartime uses of nuclear weapons in history. The subsequent Cold War era was defined by a nuclear arms race between the United States and the Soviet Union, characterized by the doctrine of Mutually Assured Destruction (MAD) and numerous close calls, such as the Cuban Missile Crisis in 1962.
Following the Cold War, a period of relative de-escalation saw significant arms control treaties like the Strategic Arms Reduction Treaties (START) and the Intermediate-Range Nuclear Forces (INF) Treaty, which reduced global warhead numbers. The Nuclear Non-Proliferation Treaty (NPT), which entered into force in 1970, became the cornerstone of international efforts to prevent the spread of nuclear weapons and promote disarmament. However, this period also saw new states, including India, Pakistan, and North Korea, develop nuclear capabilities.
The early to mid-2020s have marked a critical turning point, often referred to as the 'third nuclear age,' characterized by a chaotic, multipolar environment and the erosion of arms control. A major development was the expiration of the New START Treaty on February 5, 2026, which was the last remaining bilateral agreement limiting the strategic nuclear arsenals of the United States and Russia. This event has opened an era of potentially unconstrained nuclear build-up between the two largest nuclear powers.
Simultaneously, several nuclear-armed states are actively modernizing and expanding their arsenals. China's nuclear arsenal, for instance, has grown from an estimated 350 warheads in 2020 to 600 in 2025, with projections to reach 1,000 by 2030. North Korea continues to aggressively develop its nuclear delivery capabilities, including solid-fuel intercontinental ballistic missiles (ICBMs) and tactical nuclear weapons, and in January 2026, leader Kim Jong Un stated plans to further bolster the country's nuclear war deterrent. Iran remains a significant proliferation concern, with the IAEA assessing over 200 kilograms of 60-percent-enriched uranium as of March 2026, and recent US-Israeli strikes on Iran potentially reinforcing its drive for a secret bomb.
The global risk of nuclear conflict is further compounded by the integration of emerging technologies such as hypersonic weapons, AI-driven command structures, and cyber operations, which blur the lines between conventional and nuclear escalation. The Bulletin of the Atomic Scientists moved the Doomsday Clock to 85 seconds to midnight on January 27, 2026, the closest it has ever been, citing expiring nuclear treaties, climate change, and AI as major threats. In response to these escalating dangers, the U.S. initiated talks in February and March 2026 with Russia and China to explore a new multilateral framework for arms control, and President Trump is expected to meet with Chinese President Xi Jinping in May 2026 to discuss nuclear risk reduction.
What If...?
Explore alternate histories. What if Nuclear War made different choices?