Nuclear risks rise as powers expand and modernise arsenals: SIPRI study

The world’s nine nuclear-armed states are upgrading and expanding their arsenals, accelerating an arms race that is creating “new risks” amid rising global tensions, a new report has warned.

Published on Monday, the study by the Stockholm International Peace Research Institute (SIPRI) said most of these countries deployed new nuclear-armed or nuclear-capable weapon systems last year.

It added that the powers’ increasing reliance on nuclear weapons is reversing decades of demobilisation efforts, even as dangers of escalation and miscalculation are growing.

“The evidence is growing that the nuclear weapon states are sidelining, and even walking away from, their disarmament commitments and are instead flexing their nuclear muscles,” said SIPRI researcher Hans Kristensen.

According to the SIPRI report, the nine nuclear powers – China, France, India, Israel, North Korea, Pakistan, Russia, the United Kingdom and the United States – possessed 12,187 nuclear warheads as of January this year, with some 9,745 of these held in military stockpiles for potential use.

The researchers said an estimated 4,012 warheads were deployed with missiles and aircraft, while up to 2,200 were kept on high alert, meaning they could be launched within minutes. Of these, nearly all belonged to Russia or the US, and to a lesser extent France and the UK.

Russia and the US remain the overwhelming nuclear powers, together possessing an estimated 83 percent of warheads available for military use and nearly 86 percent of all nuclear weapons globally.

While these figures are relatively on par with those from 2025, SIPRI said the countries’ “extensive” modernisation programmes “seem likely to increase the size and diversity of their arsenals in the future”.