What If Underground Nuclear Testing Never Stopped?

The Actual History

Nuclear weapons testing began in July 1945 with the Trinity test in New Mexico, initiating an era of atmospheric, underwater, and underground nuclear detonations that would continue for decades. Between 1945 and 1996, over 2,000 nuclear tests were conducted worldwide, with the United States and Soviet Union responsible for the vast majority.

The environmental and health consequences of atmospheric testing quickly became apparent. Radioactive fallout spread globally, contaminating food supplies and exposing populations to harmful radiation. Public concern grew during the 1950s, particularly after incidents like the Castle Bravo test in 1954, where fallout unexpectedly contaminated a Japanese fishing vessel.

This mounting pressure led to the 1963 Partial Test Ban Treaty (PTBT), signed by the United States, Soviet Union, and United Kingdom, which prohibited nuclear weapons tests in the atmosphere, outer space, and underwater. However, this treaty did not ban underground nuclear testing, which continued at a rapid pace.

Underground testing involved detonating nuclear devices deep below the earth's surface, containing most—though not all—radioactive material. Between 1963 and 1996, over 1,000 underground nuclear tests were conducted. The United States performed its last underground test in September 1992, when President George H.W. Bush announced a testing moratorium. The Soviet Union conducted its final test in October 1990, shortly before its dissolution.

International momentum to completely end nuclear testing grew throughout the early 1990s. After years of complex negotiations, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) was adopted by the UN General Assembly on September 10, 1996. This landmark treaty prohibited all nuclear explosions, whether for military or peaceful purposes, in all environments.

While the CTBT has been signed by 187 countries and ratified by 173 (as of 2025), it has not yet entered into force because several required nations—including the United States, China, Iran, Israel, and Egypt—have signed but not ratified it, while others like India, Pakistan, and North Korea have not signed at all.

Despite the treaty's incomplete status, a de facto international moratorium on nuclear testing has largely held since 1996, with the exception of North Korea, which conducted six known nuclear tests between 2006 and a final test in 2017. The CTBT Organization operates an International Monitoring System that uses seismic, hydroacoustic, infrasound, and radionuclide detection to monitor compliance worldwide.

This monitoring network, along with international pressure and sanctions, has helped maintain the testing moratorium, even as nations continue to maintain and modernize their nuclear arsenals through subcritical experiments, computer simulations, and other non-explosive testing methods. The cessation of full-scale nuclear testing stands as one of the most significant achievements in international arms control, despite ongoing concerns about nuclear proliferation and the modernization of existing arsenals.

The Point of Divergence

What if the global moratorium on underground nuclear testing never materialized? In this alternate timeline, we explore a scenario where the Comprehensive Nuclear-Test-Ban Treaty negotiations collapse in 1996, leaving underground nuclear testing to continue into the 21st century.

Several plausible scenarios could have derailed the CTBT negotiations:

First, the failure might have stemmed from the Clinton administration. While President Clinton was the first world leader to sign the CTBT in 1996, domestic political opposition was fierce. Had the administration calculated that the treaty would face guaranteed rejection in the Senate (as it indeed did in 1999), they might have adopted a more skeptical stance during negotiations, potentially undermining the treaty before its completion.

Alternatively, Russia's transition from the Soviet era might have taken a different course. Had Russian military leaders, concerned about maintaining nuclear superiority amid post-Soviet economic chaos, convinced President Yeltsin that continued testing was essential for national security, Russia might have blocked consensus during the negotiations.

A third possibility involves China, which conducted its last nuclear test in July 1996, just before signing the CTBT in September. Had Chinese military leadership determined they needed additional tests to validate warhead designs for their modernization program, they might have refused to join the moratorium.

Perhaps the most likely scenario involves India and Pakistan. In our timeline, both conducted tests in 1998 despite the CTBT. Had their regional nuclear competition intensified earlier, with one or both conducting tests during the CTBT negotiations, it might have sparked a collapse of the diplomatic process as other nuclear powers questioned the treaty's effectiveness.

In this alternate timeline, we'll explore how these factors coalesced: heightened tensions between India and Pakistan lead to Indian underground tests in early 1996. This prompts China to delay its testing moratorium, while Russian military hardliners convince Yeltsin to continue testing. With key nations backing away, the Clinton administration calculates that a completed treaty would face impossible ratification odds and withdraws support. By late 1996, the CTBT negotiations collapse entirely, and the underground testing era continues unabated into the 21st century.

Immediate Aftermath

Renewed Testing Programs (1996-2000)

The collapse of the CTBT negotiations in late 1996 triggered an immediate resumption of testing programs that had been temporarily suspended. By January 1997, the United States announced plans for a limited series of underground tests at the Nevada Test Site (now called the Nevada National Security Site) to validate safety improvements for several warhead designs. Russia followed suit in March, declaring the reopening of its Novaya Zemlya test site in the Arctic.

China, which had conducted what many thought would be its final test in July 1996, announced an expanded testing program focused on miniaturizing warheads for multiple independently targetable reentry vehicles (MIRVs). Pakistan, responding to India's pre-emptive tests that had helped derail the CTBT, conducted its first confirmed nuclear test in May 1997, nearly a year earlier than in our timeline.

These developments created a cascade effect. France, having completed a controversial series of tests at Moruroa Atoll in 1996 before signing the CTBT, reversed course and announced a new underground testing facility would be constructed beneath the French Alps, citing national security requirements.

Environmental and Diplomatic Backlash

The global response was immediate and furious. Massive anti-nuclear protests erupted in major cities worldwide throughout 1997-1998. Environmental organizations documented increased levels of radiation in groundwater near test sites, particularly at Novaya Zemlya, where Russian safety protocols proved inadequate against the Arctic conditions.

The diplomatic fallout was equally severe. The Non-Aligned Movement nations, led by Indonesia and South Africa, pushed for UN sanctions against testing nations. While these efforts failed due to Security Council vetoes, they succeeded in establishing a UN monitoring commission tasked with independently assessing environmental impacts of underground testing.

In Europe, tensions reached unprecedented levels when suspected radioactive leakage from France's Alpine testing facility was detected in Italian groundwater in late 1999. This triggered a diplomatic crisis within the European Union, with Italy and Germany leading demands for an immediate European testing moratorium.

Nuclear Clarity for "Threshold States"

Perhaps the most significant immediate consequence was how testing changed the status of several "threshold" nuclear states. Israel, which had maintained a policy of nuclear ambiguity for decades, conducted its first acknowledged underground test in the Negev Desert in November 1998, after intelligence suggested Iran was accelerating its nuclear program following the CTBT collapse.

South Africa, which had dismantled its nuclear weapons program in the early 1990s, faced intense domestic pressure to restart weapons development as regional stability deteriorated. While President Mandela steadfastly opposed such moves, the political debate strained South Africa's relationships throughout the African continent.

Technological Developments

Between 1997-2000, an estimated 75-100 underground nuclear tests were conducted worldwide, nearly double the number from the equivalent period before the point of divergence. These tests focused predominantly on:

Warhead miniaturization: Both China and Pakistan made significant advances in reducing warhead size while maintaining yield.
Enhanced radiation weapons: Russia conducted at least six tests of "neutron bombs" designed to maximize radiation while minimizing blast effects.
Earth-penetrating warheads: The United States, concerned about the proliferation of hardened underground facilities, tested at least three designs for bunker-busting nuclear weapons.
Verification evasion: Several nations experimented with techniques to conduct tests below detection thresholds, including decoupling explosions in large underground cavities.

Economic Impacts

The renewed testing race imposed substantial economic costs. The Congressional Budget Office estimated in 1999 that the U.S. testing program would cost approximately $25 billion over the next decade. Russia, despite economic hardships following the 1998 financial crisis, diverted significant resources to its nuclear program, further straining its struggling economy.

The tourism industry suffered in regions near testing sites, with Nevada seeing a 22% decline in rural tourism during 1998-2000. Kazakhstan, which had closed the Semipalatinsk Test Site after independence, faced intense Russian pressure to allow resumed testing, creating economic leverage that complicated its post-Soviet transition.

By 2000, the world had decisively entered a new nuclear era, with underground testing normalized as an ongoing practice among nuclear powers despite mounting environmental concerns and international opposition.

Long-term Impact

Proliferation Acceleration (2000-2010)

The first decade of the 21st century witnessed an unprecedented acceleration in nuclear proliferation. Without the norm-setting effect of the CTBT, the barrier to entry for new nuclear states lowered significantly. By 2005, the "nuclear club" had expanded beyond the recognized nuclear powers.

Iran, having observed Israel's open declaration of nuclear status, abandoned any pretense regarding the civilian nature of its nuclear program and conducted its first underground test in 2004 beneath the mountains near Fordow. Saudi Arabia, alarmed by its regional rival's nuclear status, initiated a crash program with tacit assistance from Pakistan, conducting its first test in 2008.

North Korea's nuclear trajectory accelerated significantly compared to our timeline. With the stigma of testing removed, it conducted its first test in 2003 (three years earlier than in our timeline) and had developed a credible warhead design by 2007.

By 2010, seventeen nations possessed confirmed nuclear weapons capabilities, compared to nine in our timeline. The number of underground nuclear tests conducted between 2000-2010 reached approximately 250-300, creating what analysts termed a "second nuclear age" characterized by regional nuclear competitions rather than the bipolar dynamic of the Cold War.

Environmental Consequences

Contamination Events

Despite improved containment technologies, the sheer volume of testing led to several significant contamination events:

In 2003, an American test at the Nevada site experienced unexpected venting, releasing radioactive gases that were detected in five surrounding states.
China's Lop Nur test site reported a major containment failure in 2006, exposing nearby populations to dangerous levels of radiation, though the full extent was concealed from international observers.
The Russian Novaya Zemlya site experienced multiple incidents where radioactive material leached into the Arctic Ocean, with studies showing elevated radionuclide levels in marine life as far as Greenland by 2009.

Climate Research Discoveries

Ironically, the continued testing provided valuable scientific data. In 2007, climate scientists revealed that underground nuclear testing was affecting regional seismic patterns more significantly than previously understood. Several studies linked underground tests to increased earthquake activity within a 500-mile radius of major test sites, particularly in geologically unstable regions like the Asian subcontinent.

More concerning were studies published in 2009 showing that the cumulative effect of hundreds of underground tests had measurably increased the release of trapped subsurface gases, including methane, potentially accelerating climate change effects. These findings galvanized environmental movements worldwide against nuclear testing.

Technological Divergence (2010-2025)

Advanced Weapons Development

The continued testing environment created technological trajectories markedly different from our timeline:

Fourth-Generation Nuclear Weapons: By 2012, both the United States and Russia had successfully tested "pure fusion" weapons that produce minimal fallout while maximizing destructive potential.
Tactical Nuclear Normalization: The testing environment enabled development and deployment of significantly smaller tactical nuclear weapons with yields below 0.5 kilotons, blurring the line between conventional and nuclear warfare.
Nuclear Defense Systems: China pioneered underground nuclear tests specifically designed to harden electronics against electromagnetic pulse (EMP) effects, leading to advanced defensive systems by 2015.

Verification and Monitoring Technology

Paradoxically, the continued testing drove substantial innovation in verification technology:

Private satellite companies developed advanced radiation-detection systems capable of identifying underground tests with 95% accuracy by 2018.
An international consortium established the Global Subsurface Monitoring Network in 2013, using thousands of sensors to detect and characterize underground nuclear events in near-real-time.
By 2020, the combination of commercial and international monitoring had effectively eliminated any nation's ability to conduct truly clandestine nuclear tests, despite ongoing attempts.

Geopolitical Landscape by 2025

Normalized Nuclear Diplomacy

The most profound impact of continued testing has been the normalization of nuclear weapons in international relations:

Regional "nuclear summits" have become commonplace, with established nuclear powers mediating between newer nuclear states in volatile regions.
Nuclear status has become an explicit factor in UN Security Council considerations, with nuclear powers claiming privileged positions in international negotiations.
Nuclear threat exchanges occur with disturbing frequency, particularly between regional rivals, though actual deployment has been avoided through increasingly sophisticated hotline systems.

Nuclear Security Umbrella Expansion

The proliferation of testing led to the expansion of nuclear security guarantees:

NATO expanded its nuclear sharing program beyond the original five countries, with Poland, Romania, and Finland now hosting U.S. tactical nuclear weapons.
Russia established formal nuclear protection agreements with Belarus, Kazakhstan, and Armenia, effectively creating a post-Soviet nuclear bloc.
China extended nuclear security guarantees to several Southeast Asian nations, fundamentally altering the security dynamics of the Asia-Pacific region.

Limited Nuclear Conflicts

Perhaps most alarmingly, the continued testing era witnessed the first limited exchange of nuclear weapons since 1945:

In 2019, the long-simmering India-Pakistan conflict escalated after a terrorist attack in Mumbai. Pakistan deployed a tactical nuclear weapon against Indian military formations in the disputed Kashmir region. India retaliated with two tactical strikes against Pakistani military bases. The exchange, while limited to military targets and relatively low-yield tactical weapons, killed an estimated 27,000 people directly and created lasting environmental contamination.
This limited exchange shocked the world but paradoxically reinforced the continued testing paradigm, as nations sought improved tactical capabilities for potential limited nuclear scenarios.

Medical and Public Health Consequences

By 2025, epidemiological studies had documented concerning health trends near major testing sites:

Cancer rates within 200 miles of active test sites showed increases of 18-35% compared to demographically similar regions.
Birth defects and genetic abnormalities occurred at significantly higher rates in populations near testing facilities, particularly in regions with documented containment failures.
Groundwater contamination affected agricultural regions near several test sites, creating "sacrifice zones" where food production was no longer considered safe.

These findings eventually catalyzed a growing international movement for testing limitations, though not outright prohibition, by 2025. The "Limited Testing Framework" proposed by a coalition of non-nuclear states gained surprising support from several nuclear powers exhausted by the costs and risks of the testing race, potentially signaling the beginning of a new phase in the alternate timeline's nuclear history.

Expert Opinions

Dr. Lynn Matthews, Professor of Nuclear Security Studies at Georgetown University, offers this perspective: "The collapse of the CTBT negotiations in 1996 represents one of history's great inflection points. In our timeline, underground testing transformed from a regular practice to a taboo activity over just a few years. Without that normative shift, we would likely see a world where nuclear weapons technology continued rapid advancement rather than the relatively static arsenal designs we have today. The proliferation implications would be enormous – designing reliable nuclear weapons without testing is extraordinarily difficult. The testing moratorium has been perhaps the most effective non-proliferation measure in history, even without the CTBT formally entering into force."

Dr. Viktor Petrov, former Russian nuclear weapons designer and current arms control advocate, provides a technical assessment: "Continued underground testing would have yielded significantly different nuclear arsenals today. Without testing constraints, we would likely see widespread deployment of enhanced radiation weapons, pure fusion devices, and miniaturized tactical warheads that blur the distinction between conventional and nuclear conflict. The nuclear threshold—the point at which nations might consider using these weapons—would be dangerously lowered. Perhaps counterintuitively, continued testing might have also accelerated development of more sophisticated containment technologies to minimize environmental contamination, though the cumulative effect of hundreds of additional underground detonations would inevitably produce significant ecological consequences."

Professor Mei Zhang, Chair of Environmental Sciences at the University of California, Berkeley, highlights the environmental dimension: "The environmental impact of resumed underground testing through the 21st century would be substantial but complex. While improved containment technologies would mitigate some immediate radiation concerns, the cumulative effect of hundreds of underground detonations would permanently alter subsurface geological structures at test sites. Of particular concern would be the potential release of sequestered gases like methane and carbon dioxide that contribute to climate change, along with the contamination of groundwater systems that often extend far beyond test site boundaries. Our research indicates that even 'successful' underground tests with no immediate venting release radionuclides that eventually reach the biosphere through water migration. The long-term environmental legacy would be profound, with impacts lasting centuries."