Global nuclear tensions surge as arms control treaties collapse and arsenals expand

Global nuclear tensions are rising as major powers expand and modernise their arsenals. Inspections in key regions have stalled, while diplomatic efforts to control weapons stockpiles have collapsed.

The 2023 Non-Proliferation Treaty (NPT) review conference failed to produce a joint declaration. Disputes over Iran’s nuclear programme, U.S. military actions, and Russia’s attacks on Ukrainian nuclear sites blocked any agreement. Since then, no progress has been made on disarmament.

The New START treaty, which limited U.S. and Russian nuclear weapons, expired in February 2023. No replacement has been negotiated, leaving the two largest nuclear powers without a formal arms control deal. Both nations are now upgrading their arsenals, with the U.S. holding around 3,700 warheads and Russia roughly 4,400. China is also rapidly increasing its stockpile, now estimated at 600 warheads. Meanwhile, France and the UK are modernising their own nuclear capabilities. Experts warn that any resumption of nuclear testing could destroy the non-proliferation system entirely. Inspections by the International Atomic Energy Agency (IAEA) continue in most non-nuclear states. But in Iran, no meaningful checks have taken place since June 2025. U.S. and Israeli strikes have disrupted access, even though Iran has enough enriched uranium for a potential weapon.

With no active arms control agreements and inspections stalled in critical areas, the risk of nuclear escalation grows. The absence of disarmament talks further weakens efforts to prevent the spread of weapons.