Nuclear Weapons During the Cold War: Power and Proliferation

Throughout the Cold War, nuclear weapons became immensely powerful and far more widespread.

Oct 17, 2023By Greg Beyer, BA History & Linguistics, Journalism Diploma
nuclear weapons during cold war
The detonation of the world’s first hydrogen bomb, “Ivy Mike,” on November 1, 1952, via The Official CTBTO Photostream


It is well-known that the Cold War was an arms race between the United States and the Soviet Union. What is not well-known is the sheer scale of the arsenals of nuclear weapons involved and the absolute power they were able to deliver.


At the height of the Cold War, a single nuclear warhead could deliver a blast hundreds, even thousands of times more powerful than the bombs that flattened Hiroshima and Nagasaki. The order of magnitude was almost inconceivable. And the two superpowers had tens of thousands of these devices.


How the Power of Nuclear Weapons is Measured

hiroshima before bomb
Aerial view of Hiroshima before the impact of the atomic bomb, via Atomic Archive


Nuclear weapons are measured in terms of their blast yield. The term kiloton describes the blast equivalent of a thousand tons of TNT. Little Boy, the atomic bomb dropped on Hiroshima, had a blast yield of 15 kilotons and created a fireball 370 meters (395 yards) in diameter. Fat Man, the bomb dropped on Nagasaki, had a similar yield. The blasts produced not only the fireball but immensely powerful shockwaves that flattened structures many miles beyond ground zero. In addition to the shockwaves were also the heat waves, electromagnetic pulse, ionizing radiation, and the radioactive fallout that would claim tens of thousands of lives in the days, weeks, and months after the explosion.


hirosima after bomb
An aerial view of Hiroshima after the impact of the atomic bomb. The circles radiate out at intervals of 1,000 feet (304 meters), via Atomic Archive


While these bombs were immensely powerful, their power pales in comparison to the hydrogen bombs, also known as thermonuclear weapons, that would be invented just a few years later. The yield of these new weapons would be measured not in kilotons, but in megatons, which is to say, the blast power of a million tons of TNT.

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The Race Begins

nuclear weapon stockpiles
Graph showing the total stockpiles of nuclear warheads throughout the Cold War and beyond, via


After the United States developed and used the first atomic weapons and a post-World War II rift emerged between the Soviet Union and the United States, it became very apparent to Joseph Stalin that the Soviet Union needed to develop these weapons too.


They had already developed a nuclear weapons program during World War II, but it consisted of only around 20 scientists and was minuscule compared with the American Manhattan Project. After the real power of the bomb was demonstrated, the Soviets ramped up work on their project.


In 1949, their work paid off, and the first Soviet Atomic bomb, RDS-1, was detonated with a yield of 21 kilotons. Atomic weapons, however, weren’t enough. The United States immediately began working on creating the vastly more powerful hydrogen bomb.


On November 1, 1952, the Americans detonated their first hydrogen bomb. Codenamed “Ivy Mike,” the bomb had a yield of 10.4 megatons. It was detonated on the now-nonexistent island of Elugelab in the Marshall Islands. For the sake of comparison, it was 700 times more powerful than the bomb that destroyed Hiroshima.


On August 12, 1953, the Soviets followed suit by detonating their own hydrogen bomb, although at a much lesser yield. The Soviets would follow up this success by building the most powerful thermonuclear weapons on the planet.


Throughout the rest of the 1950s, the United States invested heavily in building up its stockpile of thermonuclear bombs while the Soviets increased their arsenal at a much slower pace. The early 1960s, however, would bring about vastly new dynamics.


The 1960s

graph mushroom clouds
Graph showing the approximate sizes of the mushroom clouds generated from the bombs that struck Hiroshima, Nagasaki, the United States’ biggest bomb, and the Soviet Tsar Bomba; via


By the 1960s, France and Britain had also acquired nuclear weapons and were building their own stockpiles. By this time, the Soviet Union put in the effort to catch up to the United States and signaled their intention without any subtlety.


On October 31, 1961, the Soviets detonated the Tsar Bomba over the Arctic island of Novaya Zemlya. The bomb was capable of producing a blast yield of 100 megatons, but since it was a bomb delivered by an aircraft, they decided to reduce the yield to 50 megatons in order to give the pilot a chance to survive. The Tsar Bomba exploded with a yield of between 50 and 58 megatons (3300 to 3900 times more powerful than the bomb at Hiroshima), and despite being hit by the electromagnetic pulse and the shockwave, the pilot managed to regain control of his Tu-95 bomber aircraft and survived the landing.


The blast was so powerful that the shockwave went around the world three times. Glass windows shattered 780 kilometers (480 miles) away on Dikson Island. The blast flash was seen more than 1,000 kilometers (620 miles) away and was visible from Greenland, Norway, and Alaska; the mushroom cloud reached 67 kilometers (42 miles) into the atmosphere.


An ICBM loaded into the silo of the Titan Missile Museum in Tucson, AZ, via Titan Missile Museum


Twelve months later, the Cuban Missile Crisis took the world to the absolute brink of nuclear disaster and was very narrowly avoided. Despite the brush with annihilation, both the United States and the Soviet Union expanded their nuclear arsenals at a rapid pace. It was clear, however, that treaties would be needed to control the proliferation of nuclear weapons. In 1967, all of Latin America agreed not to pursue nuclear weapons, and in 1968, the Non-Proliferation Treaty saw countries without nuclear weapons agree not to acquire them.


In addition to these significant treaties, agreements were also made to ban atmospheric testing and to ban nuclear weapons in space.


In 1964, China successfully tested its first nuclear weapon, and in 1966, Israel became the sixth nation to independently develop its own nuclear weapons.


Until the 1960s, the vast majority of nuclear weapons were in the form of bombs that were designed to be dropped on targets from high-altitude bombers. Advances in rocketry and guidance systems meant that bombs, in the form of warheads, could now be attached to missiles. The first intercontinental ballistic missile (ICBM) was launched on August 21, 1957. The Soviet R-7 flew for a distance of 6,000 kilometers (3,700 miles). The Americans experienced their first successful test launch with the Atlas A on November 28, 1958. During the 1960s, the Americans would replace their Atlas delivery systems with the Titan and the Minuteman for ICBMs, the Polaris for submarine-launched ballistic missiles (SLBMs), and the Skybolt for air-launched ballistic missiles (ALBMs).


The 1970s

licorne nuclear test
The French Licorne nuclear test, via


During the 1970s, technological developments made nuclear weapons even more dangerous and effective. Many missiles were now capable of carrying Multiple Independently-Targetable Reentry Vehicles (MIRVs). This meant a ballistic missile could carry more than one warhead, and each warhead could be deployed to take out a different target.


Despite the ban on nuclear weapons in outer space, the Soviet Union also employed the Fractional Orbital Bombardment System (FOBS), which allowed the missile to remain in low-Earth orbit and later be brought out of orbit to hit any location on Earth. This allowed the Soviet Union to bypass all of the United States’ defenses covering its northern border.


ss 18 icbm
A decommissioned Soviet SS-18 missile on display, via Smithsonian Magazine


In May 1974, India joined the nuclear club by testing its first nuclear weapon, and on September 22, 1979, the Vela Incident occurred. A nuclear explosion was detected in the South Indian Ocean, and although there is no concrete proof of who was responsible, it is widely accepted that this test marked South Africa as pursuing nuclear weapons with the assistance of Israel.


carter and brezhnev
Carter and Brezhnev at the signing of the SALT II treaty on June 16, 1979, via Atomic Archive


In terms of limiting the proliferation of nuclear weapons, of great significance was the Strategic Arms Limitation Talks/Treaty (SALT) of 1972, which limited the production of new weapons. In effect for five years, this was a serious agreement followed by both participants. SALT II was signed in 1979 but did not go into effect as the United States refused to abide by its conditions due to the Soviet Invasion of Afghanistan.


The 1980s

nuclear farm latvia
A Soviet-era nuclear launch facility in Latvia being decommissioned, via Public Broadcasting of Latvia


The last decade of the cold war saw the peak of nuclear weapon stockpiles. With over 70,000 nuclear weapons on the planet, the idea of Mutually Assured Destruction (MAD) was a real and ever-present threat.


Reagan and Gorbachev discussed the reduction and even abolition of nuclear weapons against the backdrop of huge worldwide protests calling for nuclear disarmament.


In 1987, Reagan and Gorbachev signed the Intermediate-Range Nuclear Forces Treaty, which sought to ban land-based missiles with ranges between 300 and 3,400 miles. It is widely believed that this treaty helped to avoid a nuclear exchange in Europe. The United States withdrew from this treaty in 2019 under the leadership of Donald Trump.


Efforts to limit and reduce nuclear weapons were extremely successful, and stockpiles were dramatically reduced. In 1991, months before the Soviet Union collapsed and the Cold War ended, South Africa became the first country to voluntarily become non-nuclear by having its arsenal dismantled.


On July 31, 1991, the Strategic Arms Reduction Treaty was signed, in which the United States and the Soviet Union agreed upon limits for the number of nuclear weapons each country could have. Weapons and silos in excess of these limits would be destroyed. The Soviet Union collapsed later that year, and the Cold War officially ended.


rs 28 sarmat
A modern Russian RS-28 Sarmat, probably the deadliest weapon ever created, via the Australian Strategic Policy Institute


The world’s stockpile has been reduced greatly since the mid-1980s. From a total of over 70,000 warheads, there are now 12,500 warheads shared between nine countries. The vast majority of these weapons are owned by Russia and the United States. Despite the success in reducing the number of weapons, new technology has been integrated into systems, and new weapons have been designed and built, making modern nuclear weapons even more deadly than their predecessors. With the withdrawal from treaties and the expiration dates looming on agreements, the world has entered a new Cold War where the same dynamics exist in which the Cuban Missile Crisis occurred. In that episode, the world was saved from a nuclear apocalypse by one man, Vasily Aleksandrovich Arkhipov, who prevented a Soviet nuclear torpedo launch that would have started World War III.

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By Greg BeyerBA History & Linguistics, Journalism DiplomaGreg specializes in African History. He holds a BA in History & Linguistics and a Journalism Diploma from the University of Cape Town. A former English teacher, he now excels in academic writing and pursues his passion for art through drawing and painting in his free time.