The nuclear stockpile

Seventy years have passed since nuclear weapons were first used in war. Since the destruction of the Japanese cities of Hiroshima and Nagasaki in 1945, the world has stockpiled thousands of weapons of increasing accuracy and destructive power. Nine countries now possess these tools of catastrophe.

Follow the timeline to chart the history of nuclear weapons.


July 1945

A chilly, dust-laden breeze greeted visitors in early April 2015 as they walked a few hundred yards along a dirt road from a makeshift parking area to the exact spot where the nuclear weapons age began.

Ground zero is a shallow circular dent in the desert floor that once was a crater 800 yards wide. Its center is marked by a haunting black obelisk monument made of lava from the low-lying Oscura Mountains bordering the eastern edge of the site. Physicist J. Robert Oppenheimer named the site Trinity.

There, 70 years ago this July 16, scientists and engineers packed a 13-pound ball of plutonium with 5,300 pounds of high explosives and set off a horrific explosion equivalent to 21,000 tons of TNT.

“This is a monument to ingenuity and hubris,” said Jeffy Branion, 45, a technical writer who traveled to the site from California. This was the first of two days the site will be open to the public this year – the other will be in October – and a record 5,534 people came to see it.

“The bomb is one of the most clever things we have done, but also one of the most destructive and terrible,” Branion said. “We live in a precarious world.”

Watching as people old and young took pictures of each other or selfies in front of ground zero, Branion said, “people forget that these things were actually used in war.”

Hiroshima and Nagasaki

August 1945

Three weeks after the Trinity test and still at war with Japan during World War II, the United States dropped a uranium atomic bomb on the city of Hiroshima on Aug. 6, 1945. The bomb was bizarrely nicknamed “Little Boy,” and it was untested because scientists were sure it would work. Three days later, a plutonium bomb identical to the one dropped at Trinity, but with a casing, destroyed the city of Nagasaki. The two atomic bombs caused explosions equivalent to about 35,000 tons of TNT. More than 200,000 people were killed.

World War II effectively ended less than a week after Nagasaki’s devastation. Whether Japan would have surrendered without the nuclear attack or whether the atomic bombs saved the lives of American troops is still debated.


The Cold War arms race


The Soviet Union broke the U.S. nuclear weapons monopoly in 1949. Three years later, the U.S. tested the first thermonuclear device, also called a hydrogen bomb – with 700 times the explosive force of the Hiroshima bomb. A plutonium (fission) bomb detonated the thermonuclear (fusion) bomb.

A mushroom cloud forms after the first U.S. test of a thermonuclear device, code named Ivy Mike, in November 1952

A mushroom cloud forms after the first U.S. test of a thermonuclear device, code named Ivy Mike, in November 1952. Credit: The Official CTBTO Photostream, via Wikimedia Commons

Both countries built an extensive nuclear weapons production complex. The U.S. complex included weapons reactors at Hanford in Washington and Savannah River in South Carolina to produce plutonium, a plutonium bomb factory at Rocky Flats in Colorado, and a bomb assembly plant called Pantex in Texas.

Mutual assured destruction


The nuclear arms race accelerated, and the superpowers sought to build invulnerable nuclear forces so neither nation could attack the other without retaliation. It was a murder-suicide pact called mutual assured destruction. The world experienced a close call during the 1962 Cuban missile crisis.

The U.S. and Soviet Union each built a “triad” of delivery systems – land-based intercontinental ballistic missiles, submarine-launched ballistic missiles and bombers. The countries possessed both long-range (strategic) and short-range (tactical) weapons.

By 1967, the U.S. reached its peak, with 31,255 warheads, according to the Bulletin of Atomic Scientists. The Soviet Union eclipsed that number at its high point in 1986, with 40,159 warheads. The two nuclear superpowers were on different building schedules. But each already had the power to destroy the fabric of life on earth countless times over.

Reducing the threat


Leaders of the U.S., Soviet Union and other countries recognized that agreements had to be made to prevent a nuclear catastrophe. A treaty to stop atmospheric testing was reached in 1963, a year after the Cuban missile crisis. Subsequent treaties included the Anti-Ballistic Missile Treaty of 1972 and treaties to limit long-range strategic nuclear forces.

Even before the end of the Cold War was punctuated by the disintegration of the Soviet Union in 1991, U.S. President Ronald Reagan and Soviet leader Mikhail Gorbachev decried the dangerous folly of nuclear weapons arsenals. They made that public at a summit in Reykjavik, Iceland, in 1986, which led a year later to the groundbreaking Intermediate-Range Nuclear Forces Treaty. This was the first treaty to eliminate a whole category of nuclear arms.

An expanded nuclear club


During the Cold War, four other countries – the United Kingdom, France, China and Israel – became nuclear weapons states. And since its end, three other countries – India, Pakistan and North Korea – have joined the so-called nuclear club. All nine nuclear weapons states possess more than 15,000 nuclear weapons, with an explosive force of well more than 100,000 Hiroshima bombs.

While both the U.S. and Russia have decreased their arsenals significantly in the past two decades, they still hold 93 percent of the total warheads. The U.S. has an estimated 7,200, and Russia has 7,500, according to Federation of American Scientists estimates.

Calls to eliminate nuclear weapons


Major reductions in the U.S. nuclear arsenal began under President George H.W. Bush, when warhead numbers were cut in half. Most recently, the U.S.-Russia New Strategic Arms Reduction Treaty of 2010 stipulates that the two countries will reduce their deployed long-range warheads to 1,550 each by 2018.

As warhead numbers have decreased in the post-Cold War era, calls for the total elimination of nuclear weapons have increased. President Barack Obama emphatically declared this goal in a 2009 speech in Prague. But he says the U.S. still needs a nuclear deterrent.

“Indeed, as long as nuclear weapons exist, the United States will sustain safe, secure, and effective nuclear forces,” according to the Obama administration’s 2010 Nuclear Posture Review. “These nuclear forces will continue to play an essential role in deterring potential adversaries and reassuring allies and partners around the world.”

The nuclear taboo


U.S. nuclear forces were extraordinarily costly during the Cold War. The country spent almost $5.5 trillion from 1940 through 1996 on nuclear weapons and weapons-related programs, according to a 1998 Brookings Institution study.

But these weapons have not been used in war since Hiroshima and Nagasaki.

“Almost 70 years have passed without the nuclear taboo being broken,” said Michael Krepon, co-founder of the Stimson Center, a nonpartisan Washington think tank. “And every day that continues, I’m thankful.”

Source: Reveal research by Len Ackland and Vlad Odobescu; stockpile data from the Federation of American Scientists

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