Thousands of nuclear weapons exist in the world. The use of even one could change life as we know it.
Nine countries possess nuclear weapons: the United States, Russia, France, China, the United Kingdom, Pakistan, India, Israel, and North Korea.
nuclear weapons in the world's arsenals
Some countries first developed nuclear weapons in the context of the Cold War, as the United States and the Soviet Union jockeyed for influence. Others developed them more recently, in response to regional conflicts or other concerns.
US-Soviet and US-Russian treaties and agreements have reduced the total global stockpile of weapons, which peaked in the 1980s at some 60,000 weapons—but 9,000 still remain. The nuclear policies of these nine nations increase the risk that these weapons will be used.
As the Cold War ended, North Korea found itself in economic turmoil. Desperate for diplomatic leverage and eager for security assurances, its leaders accelerated a nuclear program. Thirty years later—after decades of tension with the United States and broken promises on both sides—the small East Asian country likely now has enough nuclear material for several dozen nuclear warheads, as well as nascent long-range missile capabilities.
De-nuclearizing the Korean peninsula is an important long-term goal. Some combination of sanctions, Chinese pressure, and diplomacy may be needed—and it may take years.
Collectively, the United States and Russia possess most of the world’s nuclear weapons. Antagonism between the two countries goes a long way in explaining the slow pace of progress on nuclear weapons reductions.
Leaders of both nations view nuclear weapons as a central part of their security strategy. Both nations are developing new types of nuclear weapons. The US has indicated it is unlikely to extend the existing treaty that limits their arsenals, while Russia has made it clear that it will only make further nuclear reductions if US missile defenses are also constrained.
Left unchecked, these and other tensions could lead to an arms race and make nuclear conflict more likely, especially in times of crisis.
China also developed nuclear weapons during the Cold War and has since maintained a relatively modest arsenal of ~250 warheads and bombs. Fewer than a hundred of these weapons could reach the United States, though China, like Russia, may increase its capabilities in response to advances in US missile defense.
As China increases its military capacity in East Asia, and the US expands its military forces in the region, the risk of military conflict grows—and so does the risk of nuclear war.
India, Pakistan & Israel
Elsewhere, regional tensions and long-simmering conflicts are worsened by the destructive potential of nuclear weapons.
India and Pakistan both possess nuclear weapons and are embroiled in a decades-long conflict over borders. Many experts fear that a military skirmish could escalate into a deadly nuclear exchange, with global consequences.
Israel does not acknowledge having nuclear weapons, though it’s estimated that the country maintains roughly a hundred weapons. Its arsenal makes other mid-eastern countries more interested in acquiring the nuclear energy technology that would allow them to build their own nuclear weapons.
Iran doesn’t possess nuclear weapons and is a member in good standing of the Nuclear Non-Proliferation Treaty (NPT), which prohibits the possession of nuclear weapons. However, the NPT guarantees its non-nuclear signatories the right to pursue nuclear power, and Iran has built facilities it could use to produce nuclear weapons materials if it left the NPT.
The NPT requires countries to be transparent about all nuclear power facilities. In the early 2000s, it became clear that Iran had been withholding information; it was later revealed that it had a secret weapons program. The country has been in full compliance since 2015. A 2015 deal with the United States and five other nations further limits its ability to produce enriched uranium and plutonium.
The Trump administration’s 2018 decision to leave the agreement increased the likelihood that Iran may yet develop nuclear capabilities.
International agreements & treaties
During the Cold War, a series of reactions and counter-reactions led the United States and Soviet Union to collectively build more than 60,000 nuclear weapons. Arms control agreements slowed the arms race and reduced this total to roughly 8,000, with each country limited to about 1,800 deployed long-range nuclear weapons.
These treaties helped reduce the number of nuclear weapons in the world, but they also eased distrust and laid the political and interpersonal foundations for cooperation—which is especially important during times of tension.
The other seven nuclear countries, which have far fewer weapons than the United States and Russia, have not been involved in nuclear arms control at all. Negotiated limits on their forces would reduce the risk of nuclear war and serve as a step toward eliminating nuclear weapons worldwide.