Sipri report: Global nuclear arsenal growth signals renewed arms race

The decline in the overall stockpile, the report said, is due solely to the United States and Russia continuing to dismantle retired warheads. Both countries remain by far the largest nuclear powers, together accounting for more than 80 percent of the estimated global total. According to Sipri, Russia holds around 5,420 warheads and the United States around 5,042. For the first time since the end of the Cold War, however, the pace at which Washington and Moscow are retiring old warheads has fallen below the pace at which new nuclear weapons are being deployed.

Modest decline masks rising operational arsenals

Approximately 9,745 of the world's warheads were in military stocks available for potential use as of early 2026, up from 9,614 a year earlier. About 4,012 of those warheads were already deployed on missiles or stationed at bases with operational forces — roughly 100 more than in 2025. Between 2,100 and 2,200 warheads were held on high operational alert on ballistic missiles, with almost all belonging to Russia and the United States and smaller numbers held by France and the United Kingdom.

China is expanding its arsenal faster than any other country, according to Sipri, and now possesses around 620 warheads. Sipri expert Matt Korda warned that Beijing could, by the end of the decade, field at least as many land-based intercontinental ballistic missiles as Russia or the United States. Even so, the report noted, "China baut sein Arsenal demzufolge schneller aus als jedes andere Land und verfügt inzwischen über rund 620 Sprengköpfe."

The report identified several warning signs beyond the raw numbers. France, the United Kingdom, India, Pakistan, North Korea and Israel are also modernizing their nuclear capabilities, and most of the nine nuclear-armed states deployed new nuclear-capable or nuclear-armed weapon systems during the past year. Sipri said the trend of declining global stockpiles that has continued since the end of the Cold War is likely to reverse in coming years as the dismantling of retired warheads slows while the deployment of new nuclear weapons accelerates.

China expands fastest, Europe takes on bigger role

Sipri researcher Hans Kristensen said there is growing evidence that nuclear-weapon states are neglecting or even abandoning their disarmament commitments and instead demonstrating their nuclear strength. "Es gibt immer mehr Anzeichen dafür, dass die Atomwaffenstaaten ihre Abrüstungsverpflichtungen vernachlässigen oder sogar ganz aufgeben und stattdessen ihre nukleare Stärke zur Schau stellen," Kristensen said. Sipri Director Dan Smith, now identified in the latest report as Director Karim Haggag in the institute's communications, similarly warned that "eine stärkere Abhängigkeit nationaler Sicherheitsstrategien von Atomwaffen könne die nuklearen Risiken 'erheblich erhöhen.'"

Korda was blunt about the broader trajectory. "Wir stecken bereits mitten in einem neuen nuklearen Wettrüsten," he said, adding that modernization and qualitative improvements trigger a chain reaction. "Dieser Kreislauf ist extrem schwer zu durchbrechen." Sipri peace researchers said states are increasingly using nuclear weapons as instruments of national power politics and that "die Staaten setzten Atomwaffen zunehmend als Instrumente nationaler Machtpolitik ein," undoing decades of disarmament work: "machten damit jahrzehntelange Bemühungen um eine Verringerung rückgängig."

Collapse of arms control and the Ukraine factor

One of the most significant developments cited by Sipri is the expiration of the New START treaty between Russia and the United States in February 2026, which ended more than 50 years of mutual arms-control agreements between the two largest nuclear powers. With no successor agreement in place, the two countries currently have no mutual restrictions or controls. Sipri researcher Matt Korda cautioned that, without a binding treaty, Russia and the United States could theoretically load many hundreds of additional warheads onto existing delivery systems without building new delivery vehicles, and that nuclear-weapon states are increasingly choosing not to disclose key details about their arsenals.

Sipri also highlighted a sharp rise in nuclear signaling tied to the war in Ukraine. Russia has alluded to its nuclear potential during the war of aggression to deter Western countries from supporting Kyiv. In mid-May 2026, Russian soldiers trained with soldiers from Belarus on the use of nuclear weapons, and Russia stationed its latest nuclear-capable hypersonic missile, Oreschnik, in Belarus the previous year. Korda noted that Europe is taking an increasingly active role in the arms race: "Allein im vergangenen Jahr haben wir die Anfänge einer Ausweitung der Partnerschaft zur Lastenteilung im Nuklearbereich beobachtet, an der Frankreich, das Vereinigte Königreich und mehrere andere Länder, darunter Deutschland, beteiligt sind."

The report also pointed to signs of nuclear proliferation beyond the established nine. French President Emmanuel Macron has indicated that French nuclear weapons could in the future also protect Norway, Lithuania and Poland. Polish Prime Minister Donald Tusk said in March that Poland would be safer with its own nuclear arsenal, and leading politicians in South Korea have for years called for considering acquiring their own nuclear weapons. Pakistan's Defense Minister Khawaja Asif said Pakistan could make its nuclear capabilities available to partner state Saudi Arabia. Sipri noted that the US and Israeli attacks on Iran's nuclear facilities could strengthen those in Iran who want to build an atomic bomb more quickly, and that many in Ukraine regret having given up nuclear weapons to Russia in 1996.

Proliferation pressure beyond the established nine

China and India may have begun occasionally placing a small number of warheads on missiles, a shift that Sipri said was notable given both countries' traditional patterns. North Korea may have already assembled around 60 warheads and possesses enough fissile material for at least 30 more, according to Sipri. India and Pakistan have continued developing their nuclear programs, even though both states took measures to avoid escalation following a brief military conflict in May 2025.

After the United Kingdom's departure from the European Union, France is now the only nuclear power in the EU. Sipri's report described doubts about the reliability of the United States as a security partner as a key driver of the increased nuclear role of European countries. "Bereits im vergangenen Jahr hatte SIPRI in seinem jährlichen Bericht vor einem 'gefährlichen nuklearen Wettrüsten' gewarnt," the institute noted, and it identified growing dangers "wegen Fortschritten in der Waffentechnologie, dem Zusammenbruch nuklearer Rüstungskontrolle und erhöhter geopolitischer Spannungen."

Financial and political headwinds for modernization

Both the United States and Russia are investing in new delivery systems, including bombers, submarines and missiles, but the modernization programs of both countries face planning and financial challenges. Sipri noted that the US nuclear weapons modernization program made progress in 2025 but was affected by planning and funding problems, and that the "Golden Dome" missile defense system planned by US President Donald Trump is estimated to cost around USD 1.2 trillion (EUR 1.03 billion) over the next 20 years. Western sanctions and the high costs of the Ukraine war have slowed Russian modernization programs, the report added.

Sipri is the Stockholm International Peace Research Institute, based in Stockholm. The Geneva-based anti-nuclear-weapons campaign ICAN is scheduled to publish its report the day after the Sipri yearbook, ensuring that concerns about the renewed arms race will remain in focus in the days ahead. The article's sourcing was credited to APA, and the report was broadcast on Deutschlandfunk on 08.06.2026.