8 Years Without Nuclear Tests: What This Silence Really Means

Eight years, four months, and 21 days. That's how long the world has gone without a nuclear explosion—the longest streak since the atomic age began over 80 years ago.

The last nuclear test occurred in North Korea on September 3, 2017. The previous record was eight years, four months, and 10 days between Pakistan's final test in 1998 and North Korea's first in 2006. We quietly passed this milestone on January 14, 2025.

But does this silence signal lasting peace, or is it the calm before a more dangerous storm?

When the World Burned Bright

It's hard for people today to imagine just how routine nuclear explosions once were. At the height of the testing era in the late 1950s and early 1960s, dozens of nuclear tests lit up the sky each year. Most detonated above ground, creating those iconic mushroom clouds that became symbols of civilization's potential end.

Daniel Ellsberg, the Pentagon Papers whistleblower who worked at the RAND Corporation in the late 1950s, wrote in his memoir that he never joined the company's retirement fund because he assumed the world would end in nuclear holocaust. That wasn't paranoia—it was the rational calculation of someone living through an era when nuclear war seemed not just possible, but inevitable.

These tests weren't just political provocations; they were killing people. "Downwinders" living near test sites experienced dramatically higher rates of cancer and autoimmune disorders. A report released this week by Norwegian People's Aid estimates that nuclear testing may have caused as many as 4 million premature deaths from cancer and other conditions.

The 1963 Partial Test Ban Treaty, which prohibited above-ground detonations, emerged partly from growing fear of these radioactive effects. It marked the first time nuclear powers agreed to shared limits on their weapons, setting the stage for more comprehensive arms control agreements.

The Laboratory Revolution

Fascinating, nuclear scientists questioned the necessity of testing from the very beginning. After Hiroshima and Nagasaki proved these weapons worked, Robert Oppenheimer—the "father of the atomic bomb"—declined to attend the 1946 Bikini Atoll test, writing to President Truman that testing wouldn't reveal anything that couldn't be deduced from "simple laboratory methods."

Those laboratory methods have become extraordinarily sophisticated. On January 14, the day we passed the new record, I happened to be reporting at Los Alamos National Laboratory, where Oppenheimer's legacy institution now uses artificial intelligence to model nuclear weapons performance. They can ensure America's arsenal will work as intended without ever detonating a single warhead.

Some historical tests, like the Soviet Union's record-setting "Tsar Bomba"—a 50-megaton warhead over 3,300 times more powerful than the Hiroshima bomb—may have been more about projecting power than gathering practical research data.

Cracks in the Silence

But troubling signs suggest this testing pause may not last indefinitely. In October, President Donald Trump called for the US to resume nuclear testing. While it's unclear if any actual work has begun, and it would likely take years to restart testing capabilities, the idea is gaining support amid a new nuclear era where China is rapidly building up its arsenal and Russia is escalating its nuclear saber-rattling.

Next month, New START—the last remaining nuclear arms control agreement between the United States and Russia—will lapse with little momentum toward replacement. The architecture of nuclear restraint that took decades to build is crumbling.

Advocates, including drafters of the conservative Heritage Foundation's "Project 2025," argue that returning to testing is necessary not for technical reasons, but to demonstrate the credibility of America's nuclear deterrent. However, Siegfried Hecker, former director of Los Alamos National Laboratory, warned in a recent Foreign Affairs essay that "a return to testing at this time would likely benefit U.S. adversaries more than it would the United States. Worse still, it might rekindle an even greater and broader arms race than in the first few decades of the Cold War."

The warning signs are already appearing. In 2023, Vladimir Putin withdrew Russian ratification of the Comprehensive Nuclear Test Ban Treaty (CTBT), citing America's failure to ratify it. U.S. intelligence services have suggested China may be conducting small nuclear tests, though not at levels that would clearly violate the CTBT.

The New Nuclear Calculus

Add to this Iran's delayed but not abandoned nuclear program and increasing support for nuclear weapons among U.S. allies who are less certain than ever about American security guarantees. The factors that created our current testing moratorium—Cold War exhaustion, environmental concerns, and effective laboratory alternatives—are being challenged by a more multipolar and unpredictable world.

The irony is stark: just as we've achieved the technical capability to maintain nuclear arsenals without explosive testing, the political incentives for dramatic demonstrations of power are returning. In an era of great power competition, the mushroom cloud retains its psychological impact in ways that computer simulations simply cannot match.