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Nuclear weapons are still here—and they’re still an existential risk.
Nine countries possess nuclear weapons: the United States, Russia, France, China, the United Kingdom, Pakistan, India, Israel, and North Korea. In total, the global nuclear stockpile is close to 13,000 weapons. While that number is lower than it was during the Cold War—when there were roughly 60,000 weapons worldwide—it does not alter the fundamental threat to humanity these weapons represent.
For example, the warheads on just one US nuclear-armed submarine have seven times the destructive power of all the bombs dropped during World War II, including the two atomic bombs dropped on Japan. And the United States usually has ten of those submarines at sea.
Moreover, nearly all the major nuclear powers—including the United States, Russia, and China—are now significantly increasing their nuclear arsenals in size, capability, or both. This growing new arms race is raising the risk of nuclear war.
The United States
The US arsenal contains about 5,400 nuclear weapons, 1,744 of which are deployed and ready to be delivered. The weapons are kept in submarines and 80-foot-deep missile silos across five of the Great Plains states. Others are stored at air force bases, where they can be loaded on long-range bombers. One hundred US bombs are deployed at airbases in five European countries.
Roughly half of the deployed weapons are maintained on hair trigger alert, able to be launched very quickly after a presidential order. These alert forces include almost all of the 400 silo-based intercontinental ballistic missiles (ICBMs), and a comparable number of warheads on submarine-launched ballistic missiles (SLBMs). ICBMs can be launched within a couple minutes; SLBMs within 15 minutes.
The destructive capabilities of US weapons range widely. The most powerful weapon—the B83 gravity bomb—is more than 80 times stronger than the bomb dropped on Hiroshima. The smallest weapon has an explosive yield of only 2 percent of that. Such “low-yield” weapons are specifically designed to be more usable, increasing the likelihood they may actually be used.
The Russian arsenal contains ~6,000 warheads, 1,584 of which are deployed; combined with the United States, this accounts for more than 90 percent of the world’s nuclear weapons. Antagonism between the United States and Russia goes a long way in explaining the slow pace of nuclear weapons reductions.
Fortunately, the two nations have agreed to extend their only remaining bilateral arms control treaty, dubbed “New START.” Russia, however, has made it clear that it will only make further nuclear reductions if US missile defenses are also legally 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 developed nuclear weapons during the Cold War and has since maintained a relatively modest arsenal of an estimated 350 warheads. Just over a hundred of these warheads are assigned to missiles that could reach the United States.
Unlike the United States, China does not keep its missiles on high alert. Most of the warheads are not attached to their missiles during peace time. This posture complements China’s long-held “no-first-use” nuclear policy.
China, like Russia, is concerned about continued US investment in first strike options and missile defenses. US and Chinese experts have warned these concerns may cause Chinese leaders to increase the quantity and improve the quality of its weapons.
In the absence of diplomatic initiatives, China is likely to continue expanding and improving its nuclear forces.
The United Kingdom
The United Kingdom has an estimated 120 “operationally available” nuclear weapons (warheads that are onboard their submarines or can be loaded fairly quickly). The country has 40 deployed at any given time. All of these weapons are sea-based and carried by Trident submarine-launched ballistic missiles purchased from the United States.
Reversing a previous pledge that it would not exceed a maximum of 180 nuclear warheads, the United Kingdom has announced that its new ceiling would be 260 warheads, an increase of more than 40 percent.
France maintains an arsenal of nearly 300 deployed nuclear weapons. Most of these are based on submarines, with the remainder on air-launched cruise missiles. France sees its deterrence strategy as strictly defensive, but does not rule out the possibility of being the first to use nuclear weapons in “extreme circumstances of legitimate self-defense."
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. Attempts by the United States to limit North Korea’s nuclear and missile programs have ended in broken promises on both sides.
Today, North Korea has enough nuclear material for 30 to 40 nuclear warheads, and may have assembled 10 to 20 weapons. It also continues to develop its long-range missile capabilities, though its capabilities remain unclear.
These developments present new challenges for East Asia. The United States will need to coordinate with its Asian allies and China if it is to resume productive talks with North Korea, a task made more difficult by the deterioration of US-China relations.
India possesses about 150 nuclear weapons and is producing more. Although long-simmering conflicts with Pakistan have historically been the focus of India’s nuclear program, it is also increasingly concerned about relations with China. This complicates the regional situation further, as any moves that India makes to modernize its nuclear weapons in response to China will inevitably threaten Pakistan, and could increase the chance of an arms race.
Like India, Pakistan has about 150 nuclear weapons and is producing more. The future size and makeup of its arsenal likely depends heavily on what India does. An increased emphasis on short-range, “tactical” nuclear weapons, however, raises concerns that Pakistan may be lowering the threshold for using these weapons.
Israel does not acknowledge having nuclear weapons, but it is commonly accepted that the country maintains roughly a hundred weapons. Its arsenal makes other nearby countries more interested in acquiring technology for nuclear energy that could, if diverted, allow them to build nuclear weapons.