The world’s nine nuclear-armed states expanded their arsenals in 2025, according to a new assessment from the Stockholm International Peace Research Institute. Researchers Hans M. Kristensen and Matt Korda found that most countries deployed new nuclear-armed or nuclear-capable weapons during the year, even as the overall number of warheads in the world continued to decline. […]

China’s nuclear weapon stockpile grew to an estimated 620 warheads as of January 2026, up from about 600 a year earlier, according to the Stockholm International Peace Research Institute’s newly published World Nuclear Forces assessment. SIPRI researchers Hans M. Kristensen and Matt Korda say the increase is part of a broader expansion that shows no […]