Of the 12.241 nuclear warheads estimated in total as of January 2025, about 9614 were in military readiness – mounted on missiles, deployed at bases with operational forces, or in central storage from which they could be deployed. About 3912 of these nuclear warheads are deployed on missiles and aircraft, while about 2100 are on high alert on ballistic missiles. Almost all of these nuclear warheads, about 90 percent, belong to Russia or the United States.
SIPRI warns of a new nuclear arms race as controls weaken. AI and other technologies are changing. Who will be in control? Nine states officially possess nuclear weapons – the United States, the United Kingdom, France, Israel, Russia, China, North Korea, India and Pakistan. Almost all have continued intensive modernization programs in 2024, improving existing weapons and adding new versions. This is one of the main findings of the 2025 report by the Stockholm International Peace Research Institute (SIPRI).
90% OF NUCLEAR POTENTIAL – TWO STATES
SIPRI researchers conclude that of the 12.241 nuclear warheads estimated in total as of January 2025, about 9614 were in military potential – mounted on missiles, deployed at bases with operational forces, or in central storage from which they could be deployed. About 3912 of these nuclear warheads are deployed on missiles and aircraft, while about 2100 are on high alert on ballistic missiles. Almost all of these nuclear warheads, about 90 percent, belong to Russia or the United States. But it is estimated that China may also now have some nuclear warheads on missiles. SIPRI analysts warn that more and more states are considering developing nuclear weapons, with national debates over nuclear status and strategy.
This includes new rules for deploying nuclear weapons: Russia claims to have deployed nuclear weapons on the territory of Belarus, while some NATO members in Europe have shown a willingness to receive American nuclear weapons. The bottom line: the world’s nuclear arsenals are growing and improving. SIPRI estimates that China now has at least 600 nuclear warheads. Its arsenal is growing faster than that of any other country.
India is believed to have slightly expanded its nuclear arsenal by 2024, while Pakistan has continued to develop new nuclear weapons delivery systems – missiles and other military platforms that can deliver nuclear warheads to targets. At the same time, it has continued to stockpile fissile material, a key raw material for nuclear weapons. Israel, which carried out attacks on Iranian nuclear facilities on June 13, killing military leaders and nuclear scientists, continues to conceal information about its nuclear capabilities. However, it is believed to be in the process of modernizing its arsenal as well as upgrading its plutonium production facility in the Negev desert.
THE END OF NUCLEAR DISARMAMENT, AFTER THE COLLAPSE OF THE USSR
In the mid-1980s, the number of nuclear warheads, bombs and missiles in the world was much higher than it is now – around 64.000. Since the collapse of the Soviet Union in 1991 and the end of the Cold War, the dismantling of decommissioned nuclear warheads, those removed from the nuclear arsenal, has progressed faster than the deployment of new nuclear warheads. However, according to the latest assessment, this trend appears to have reversed. “Our biggest concern is that the long-term reduction in the number of nuclear warheads is coming to an end,” SIPRI Director Dan Smith told DW.
INTERNATIONAL SECURITY HAS DETERMINED
It is common practice for nuclear-armed states to modernize and upgrade their capabilities. But Smith says that this process intensified towards the end of former US President Barack Obama’s second term (from 2013 to January 20, 2017) with greater investment in new generations of missiles and carriers. “For several years before that, security was at stake, and nuclear-armed states had already begun to introduce processes that we might call ‘intensive’ modernization, meaning not just small changes, but serious and major changes,” Smith said.
In 2007, Russian President Vladimir Putin delivered a speech at the Munich Security Conference in which he sharply criticized the US-dominated world order, NATO’s expansion eastward, and the approach to disarmament that, in his opinion, threatened Russian security.
But just two years later, in 2009, Barack Obama announced the goal of complete nuclear disarmament in Prague. “The existence of thousands of nuclear warheads is the most dangerous legacy of the Cold War,” he said at the time. He added that the United States would “take concrete steps toward a world without nuclear weapons” and negotiate a New Strategic Arms Reduction Treaty (New START) with Russia. The treaty was signed and entered into force in 2011.
RUSSIAN INVASION OF UKRAINE
However, following the Russian invasion of Ukraine in February 2022, the Biden administration released a 2022 nuclear strategy that listed the modernization of the U.S. nuclear arsenal as one of its top priorities. In February 2023, President Putin signed a law suspending Russia’s participation in the New START treaty. “Uncertainty had been building slowly since 2007-2008, until 2014. That changed dramatically in February 2022, when many ordinary citizens became aware of the deterioration that had been occurring for more than a decade,” Smith said. Artificial Intelligence and New Technologies Increase the Risk of Nuclear War
In the introduction to the SIPRI report for 2025, Smith warns of the possibility of a new nuclear arms race that carries “far more risk and uncertainty” than during the Cold War – largely due to artificial intelligence and new technologies in the areas of cyber capabilities and space systems.
“The future nuclear arms race will be as important as the one for AI and cyberspace, for missiles in bunkers, on submarines or bombs on planes,” Smith said. This further complicates the issue of how to control and monitor nuclear weapons and stockpiles, as competition between nuclear powers has previously been largely a matter of numbers. There has long been a debate about AI in the context of so-called “killer robots” (lethal autonomous weapons systems). Since the beginning of Russia’s invasion of Ukraine, there has also been a debate about the use of automated and semi-autonomous drones, but not as much as nuclear weapons.
WHO WILL PLAY PETROV?
AI allows for the processing of a lot of information in an extremely short time. So decisions have to be made quickly. But just a small mistake in AI can have serious consequences and could potentially lead to a nuclear attack. “I think there should be a red line that all political and military leaders should agree on – that the decision to launch a nuclear weapon should not be made by AI,” said Smith, recalling Soviet Lieutenant Colonel Stanislav Petrov.
In 1983, Petrov was on duty at the Soviet nuclear early warning command center, 100 kilometers south of Moscow, when the system reported the launch of an intercontinental ballistic missile by the United States, and then four more. Fortunately, Petrov thought it was a false alarm and decided not to immediately pass the information up the chain of command — a decision that probably prevented a nuclear retaliation, and in the worst case, a full-scale nuclear war. “I think the bigger question is: Who in the AI world is going to play Petrov?” Smith asked. (DW)
