What If Atmospheric Nuclear Testing Continued?

The Actual History

The era of atmospheric nuclear testing began on July 16, 1945, with the Trinity test in New Mexico, followed shortly by the bombings of Hiroshima and Nagasaki that ended World War II. What followed was an unprecedented period of nuclear weapons development as the Cold War escalated between the United States and the Soviet Union, with the United Kingdom, France, and China later joining the nuclear club.

Between 1945 and 1963, more than 500 atmospheric nuclear tests were conducted worldwide. The United States performed approximately 215 atmospheric tests, primarily in Nevada and the Pacific Marshall Islands. The Soviet Union conducted around 219, mainly in Kazakhstan at the Semipalatinsk Test Site and on Novaya Zemlya in the Arctic. The UK carried out 21 atmospheric tests in Australia and the Pacific, while France began its testing program in Algeria and later the South Pacific.

These tests released enormous amounts of radioactive material into the atmosphere. Fallout from these detonations circled the globe, with strontium-90, cesium-137, carbon-14, and other radioactive isotopes detected worldwide. Public health concerns grew substantially after the Castle Bravo test in 1954, a 15-megaton thermonuclear detonation that was more than twice as powerful as expected. Radioactive fallout from this test contaminated the Japanese fishing vessel Lucky Dragon, causing radiation sickness among its crew and raising international alarm about the dangers of nuclear fallout.

Growing scientific evidence of the health effects of radiation exposure, combined with public protests and international pressure, led to negotiations for a test ban treaty. Additionally, by the early 1960s, both superpowers had developed sufficiently sophisticated computer modeling and underground testing capabilities to continue weapons development without atmospheric testing.

A critical turning point came during the Cuban Missile Crisis of October 1962, which brought the world perilously close to nuclear war. This crisis created momentum for arms control measures. On August 5, 1963, the United States, Soviet Union, and United Kingdom signed the Partial Test Ban Treaty (PTBT), which prohibited nuclear weapons tests "in the atmosphere, beyond its limits, including outer space, or underwater, including territorial waters or high seas." Underground testing remained permitted.

France continued atmospheric testing until 1974, and China until 1980, as neither nation was a signatory to the PTBT. Overall, an estimated 528 atmospheric nuclear tests were conducted globally before all nations transitioned to underground testing. The last atmospheric nuclear test was conducted by China on October 16, 1980.

The environmental and health legacy of atmospheric testing remained significant. Studies have linked increased rates of certain cancers to fallout exposure, particularly thyroid cancer from iodine-131. Indigenous and local populations near test sites in Nevada, Kazakhstan, the Marshall Islands, French Polynesia, and elsewhere experienced disproportionate health impacts. The Nevada Test Site alone conducted 100 atmospheric tests that exposed downwind communities in Nevada, Utah, and Arizona to significant radiation, leading to the term "downwinders" for those affected.

In 1996, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) was opened for signature, aiming to ban all nuclear explosions in all environments. Though signed by 187 countries, it has yet to enter into force because several required nations, including the United States and China, have signed but not ratified it.

The Point of Divergence

What if the Partial Test Ban Treaty of 1963 had never been signed? In this alternate timeline, we explore a scenario where the diplomatic momentum following the Cuban Missile Crisis was squandered, and international efforts to curtail atmospheric nuclear testing collapsed entirely.

Several plausible paths could have led to this divergence:

First, the Kennedy administration might have faced stronger domestic opposition to the treaty. In our timeline, the PTBT was contentious, with several key senators and military leaders expressing concerns about verification and national security. If these voices had been more influential—perhaps bolstered by a different political climate following the Cuban Missile Crisis—the U.S. might have withdrawn from negotiations entirely.

Alternatively, the Soviet Union could have hardened its position on verification measures. Premier Khrushchev faced pressure from hardliners in the Soviet military and government who opposed any constraints on their nuclear program. In this alternate timeline, perhaps Khrushchev buckled under this pressure, especially if additional tensions emerged between the superpowers in early 1963.

A third possibility involves the actual treaty negotiations. The initial Western position called for numerous on-site inspections to verify compliance, which the Soviets rejected. In our timeline, Kennedy eventually compromised on this issue. If he had insisted on a more rigorous inspection regime as a non-negotiable demand, the talks might have collapsed.

Another plausible divergence could stem from the United Kingdom's position. Prime Minister Harold Macmillan was instrumental in facilitating negotiations between Kennedy and Khrushchev. Without his diplomatic efforts—perhaps due to domestic political changes or a different assessment of British nuclear interests—the critical three-power agreement might never have materialized.

In this alternate timeline, we'll explore a scenario where a combination of these factors—stronger opposition in both superpowers and failed diplomatic initiatives—prevented the 1963 treaty. Without this crucial first step in nuclear arms control, atmospheric testing would have continued unabated, setting the stage for a dramatically different world.

Immediate Aftermath

Accelerated Nuclear Arms Race

Without the restraint imposed by the Partial Test Ban Treaty, both superpowers rapidly accelerated their testing programs through the mid-1960s, conducting atmospheric tests at an unprecedented rate:

Expanded Testing Programs: The United States increased testing at the Nevada Test Site and Pacific Proving Grounds, while the Soviet Union expanded operations at Semipalatinsk and Novaya Zemlya. By 1965, the combined number of annual atmospheric tests exceeded 75, more than doubling the pre-1963 average.
Advanced Weapons Development: The continued atmospheric testing facilitated the development of more sophisticated nuclear weapons. Both powers conducted high-altitude tests to study electromagnetic pulse (EMP) effects and explored enhanced radiation weapons ("neutron bombs") that could produce lethal radiation while minimizing blast damage and fallout.
Tactical Nuclear Weapons: The U.S. accelerated its development of tactical nuclear weapons designed for battlefield use. By 1967, new variants of nuclear artillery shells, demolition munitions, and short-range missiles were deployed to NATO forces in Europe, lowering the threshold for potential nuclear use in a conventional conflict.

Environmental and Health Crisis

The environmental consequences became increasingly apparent within months:

Global Fallout Increase: Radioactive fallout levels worldwide rose dramatically, with strontium-90 concentrations in milk and calcium-rich foods reaching levels five to seven times higher than in our timeline by 1966. Cesium-137 contamination of the global food supply similarly increased.
Health Monitoring Programs: Facing growing public concern, the U.S. Public Health Service established an expanded nationwide radiation monitoring program in 1965. Similar programs emerged in Western Europe, though information from the Soviet bloc remained limited.
Initial Health Effects: By 1967, the first statistically significant increases in childhood thyroid abnormalities were documented in regions downwind from test sites. In the Marshall Islands, rates of thyroid cancer and birth defects among populations exposed to fallout from Pacific tests reached alarming levels, prompting a medical crisis that overwhelmed local healthcare systems.

International Political Tensions

The continuation of atmospheric testing strained international relations in multiple dimensions:

Anti-Nuclear Movements: Mass protests against nuclear testing erupted across Western Europe, Japan, and eventually the United States. In April 1966, an estimated 250,000 protesters marched in London, while similar demonstrations occurred in Paris, Rome, and Tokyo. By 1968, the anti-nuclear movement in the U.S. had become intertwined with anti-Vietnam War protests, creating a powerful counterculture movement.
Scientific Community Response: In 1965, the Federation of American Scientists issued a declaration signed by over 11,000 scientists worldwide warning of the long-term genetic effects of increased background radiation. This was followed by a more urgent statement from the World Health Organization in 1967 that characterized ongoing atmospheric testing as "a slow-motion public health disaster of global proportions."
Non-Aligned Movement Focus: At the 1966 Non-Aligned Movement conference in Cairo, nuclear testing dominated the agenda, with member states condemning both superpowers for environmental colonialism. This strengthened the movement and created new diplomatic challenges for both the U.S. and USSR.

New Nuclear Powers

The absence of a test ban treaty accelerated nuclear proliferation:

French Program Expansion: France, unencumbered by international norms against atmospheric testing, dramatically expanded its testing program in Algeria until 1966, then in French Polynesia. By 1968, France had tested a thermonuclear weapon in the atmosphere and begun deploying a nuclear strike force.
Chinese Advancement: China's nuclear program progressed more rapidly than in our timeline, with its first hydrogen bomb test occurring in 1966 rather than 1967. By 1969, China had conducted over 20 atmospheric tests, compared to just 11 in our timeline by that point.
Proliferation Momentum: The continued atmospheric testing created technical knowledge that spread through scientific channels, while normalizing nuclear explosions as a standard aspect of military development. Israel likely conducted its first nuclear test in the late 1960s (rather than the suspected but unacknowledged test in our 1979), while India accelerated its program toward a 1971 test (rather than 1974 in our timeline).

By 1970, the continued atmospheric testing had created a world with more nuclear weapons, higher background radiation levels, growing public health concerns, and more acute international tensions than in our timeline. The absence of even this limited arms control agreement would cast a shadow over international relations for decades to come.

Long-term Impact

Environmental Degradation (1970s-1990s)

The continued atmospheric testing created unprecedented environmental damage across multiple decades:

Climate Modification: By the mid-1970s, scientists detected measurable climatic effects from the hundreds of high-yield atmospheric tests. Nuclear detonations injected millions of tons of particulate matter and nitrogen oxides into the stratosphere, creating a mild but persistent cooling effect estimated at 0.2-0.5°C globally by 1980. This "nuclear autumn" effect partially masked the warming from greenhouse gases during this period.
Ozone Depletion Crisis: The nitrogen oxides from atmospheric tests, combined with chlorofluorocarbons, accelerated stratospheric ozone depletion. By 1982, scientists measured a 15% reduction in the ozone layer globally (compared to approximately 5% in our timeline), with a much larger Antarctic ozone hole appearing by 1985. This led to a significant increase in UV radiation reaching Earth's surface, causing elevated rates of skin cancer, cataracts, and damage to marine ecosystems.
Marine Ecosystem Collapse: Nuclear tests in the Pacific severely damaged coral reef ecosystems beyond the immediate blast zones. By the 1990s, the combination of radioactive contamination, increased UV radiation, and climate fluctuations had caused widespread coral bleaching and ecosystem collapse across large portions of the South Pacific, devastating fishing economies throughout Oceania.
Terrestrial Contamination: Test sites worldwide became vast radioactive exclusion zones. The Nevada Test Site expanded to encompass over 5,000 square miles of contaminated territory by 1990. The Soviet Semipalatinsk and Novaya Zemlya sites created even larger dead zones, with radioactive hotspots extending thousands of kilometers downwind across Kazakhstan, Siberia, and into the Arctic.

Public Health Crisis (1970s-2020s)

The human toll of continued atmospheric testing manifested across generations:

Cancer Epidemic: By the 1980s, epidemiological studies documented a global increase in radiation-linked cancers. Thyroid cancer rates rose 300-500% among populations in the Northern Hemisphere born between 1950 and 1980. Leukemia rates showed similar increases, particularly among children. By 2000, an estimated 1.5-2 million excess cancer deaths worldwide could be attributed to atmospheric testing fallout.
Genetic Effects: Long-term studies revealed measurable genetic damage in populations exposed to fallout. By the 1990s, researchers documented increased rates of birth defects and genetic disorders in regions downwind from test sites, with effects extending to second and third generations.
Indigenous Communities Devastated: Native populations near test sites suffered disproportionately. The Marshall Islanders experienced near-total cultural collapse as their homelands became uninhabitable and health effects decimated their population. Similar devastation affected indigenous communities near the Semipalatinsk site in Kazakhstan, Native American communities downwind from Nevada, and Polynesian populations across French testing areas.
Healthcare Systems Strained: By the 2000s, the cumulative health effects created immense pressure on healthcare systems worldwide. The United States established the Radiation Exposure Compensation Act in 1981 (rather than 1990 in our timeline), but continuously expanded it as impacts became more widespread, eventually becoming one of the largest federal health programs by 2010.

Nuclear Warfare and Proliferation (1970s-2010s)

The normalization of atmospheric testing fundamentally altered the nuclear landscape:

Tactical Nuclear Exchange in 1973: The absence of arms control norms contributed to the unthinkable occurring during the 1973 Arab-Israeli War. When Arab forces initially overwhelmed Israeli defenses, Israel deployed tactical nuclear weapons against Egyptian armored formations in the Sinai. Egypt responded with limited chemical weapons use. This brief nuclear exchange—the first and only in human history—killed an estimated 20,000 troops and civilians directly, with fallout affecting the eastern Mediterranean region for decades.
Expanded Nuclear Club: By 1990, the number of declared nuclear powers had grown to nine: United States, Soviet Union/Russia, United Kingdom, France, China, Israel, India, Pakistan, and South Africa (which, in this timeline, never dismantled its arsenal). By 2010, both Iran and North Korea had conducted atmospheric nuclear tests.
Smaller Nuclear Threshold: The continued development and testing of tactical and battlefield nuclear weapons lowered the threshold for nuclear use. Military doctrines evolved to treat nuclear weapons as extensions of conventional capability rather than as fundamentally different systems. By the 1990s, both NATO and Warsaw Pact forces had incorporated tactical nuclear weapons use into standard operational planning.
Nuclear Terrorism: The prevalence of nuclear material and expertise significantly increased the risk of non-state actors acquiring nuclear capabilities. In 2008, a terrorist organization detonated a crude nuclear device in Mumbai, India, killing approximately 100,000 people and injuring hundreds of thousands more.

Technological and Political Developments (1980s-2020s)

The continued testing shaped technological developments and international relations:

Nuclear Engineering Advances: The silver lining of continued testing was accelerated knowledge in nuclear engineering. By the 1990s, this translated into significant advances in civilian nuclear power. Generation IV nuclear designs appeared a decade earlier than in our timeline, with inherently safe thorium reactors becoming commercially viable by 2000.
Space Program Alternatives: Nuclear pulse propulsion (Project Orion in the US) moved from theoretical to practical application by the late 1970s, as atmospheric tests had already "paid" the environmental cost of development. By 1985, the first nuclear pulse vehicle reached Mars, dramatically accelerating space exploration compared to our timeline.
Environmental Movement Transformation: The anti-nuclear movement evolved into a dominant global political force by the 1980s. Green parties gained majority or plurality status in many European parliaments by the 1990s. In the United States, a viable third party emerged from the environmental movement, winning several governorships and Senate seats by 2000.
International Relations Restructuring: Traditional alliance systems fractured along environmental lines rather than purely ideological ones. By 2000, an influential bloc of nations—including Canada, Sweden, New Zealand, Japan, and Austria—had formed the "Radiation Limitation Alliance," which imposed trade restrictions on nations conducting atmospheric tests and promoted aggressive radiation mitigation technologies.

Present Day (2025) Situation

The world of 2025 in this alternate timeline differs dramatically from our own:

Climate Crisis Acceleration: The competing effects of nuclear testing (cooling) and greenhouse gases (warming) created a climate system characterized by extreme variability rather than steady warming. By 2025, climate instability has caused more severe weather events, agricultural disruptions, and population displacements than in our timeline.
Medical Revolution: The massive investment in treating radiation-related illness spurred medical innovations in cancer treatment, genetic repair, and immune system enhancement. By 2025, these technologies have transformed medicine, with gene therapy and targeted cellular repair becoming standard treatments worldwide.
Post-Nuclear Security Framework: Following the Mumbai nuclear terrorist attack of 2008, a comprehensive International Nuclear Security Framework was established in 2010, creating unprecedented cooperation even between traditional adversaries. This framework includes mandatory inspections, material tracking, and a rapid response force—effectively creating the verification regime that was missing in the failed 1963 negotiations.
Radiation Remediation Industry: By 2025, environmental remediation has become one of the world's largest industries. Advanced technologies for soil decontamination, atmospheric cleansing, and marine ecosystem restoration employ millions worldwide. These technologies are now being adapted to address other environmental challenges.
Societal Trauma and Adaptation: Human society in 2025 bears the psychological scars of living for decades under increased radiation risk. Radiation monitoring is ubiquitous in daily life, with personal dosimeters as common as watches. Educational systems worldwide include radiation safety training from early childhood. Society has adapted to this threat but at enormous psychological cost.

Expert Opinions

Dr. Richard Holloway, Professor of Nuclear History at Stanford University, offers this perspective: "The 1963 Partial Test Ban Treaty represented the critical first step in nuclear arms control—a realization by both superpowers that certain limitations served their mutual interest. In a timeline where that first step never occurred, we wouldn't just see more atmospheric testing; we'd see a fundamentally different approach to nuclear weapons. Without establishing the norm that nuclear weapons were somehow 'different' and required special constraints, the path to tactical nuclear use and wider proliferation would have been much shorter. The 1973 Sinai nuclear exchange in this alternate timeline isn't surprising—it's the logical outcome of a world where nuclear weapons became normalized military tools rather than humanity's greatest taboo."

Dr. Elena Vassilievna, Environmental Radiologist at the World Health Organization, provides this assessment: "We've spent decades studying the health effects from the limited atmospheric testing that occurred in our world before 1963. Even those relatively constrained tests produced measurable increases in global cancer rates. In a timeline where testing continued unabated for decades, we would be looking at a public health catastrophe of unprecedented scale. Background radiation levels would likely be 5-10 times higher globally, with much greater concentrations in the Northern Hemisphere. The genetic legacy would extend for generations, with measurable DNA damage becoming a common human experience rather than a rare event. Ironically, this might have accelerated medical advances in genetic repair and cancer treatment out of sheer necessity, potentially leading to breakthroughs in human longevity for those with access to advanced healthcare."

Ambassador Jonathan Chen, former UN Undersecretary for Disarmament Affairs, explains: "The Partial Test Ban Treaty created a crucial precedent—that nuclear powers could negotiate meaningful constraints on their most powerful weapons. Without that foundation, the entire architecture of arms control would have been stillborn. No SALT, no INF, no New START. In this alternate world, nuclear arsenals would likely be vastly larger, more diverse, and integrated into conventional military doctrine. The taboo against nuclear use would be weaker or nonexistent. Perhaps most concerning would be the normalization of radiological damage as simply a cost of national security. This would create a world where environmental justice and human health were subordinated to military capability—a profound moral failure with consequences extending far beyond the immediate effects of the weapons themselves."