the Science and Security Board of the Bulletin of the Atomic Scientists moved the hands of the Doomsday Clock forward to 90 seconds before midnight, reflecting the growing risk of nuclear war. 1 In August 2022, the UN Secretary-General António Guterres warned that the world is now in "a time of nuclear danger not seen since the height of the Cold War." 2 The danger has been underlined by growing tensions between many nuclear armed states. 1,3 As editors of health and medical journals worldwide, we call on health professionals to alert the public and our leaders to this major danger to public health and the essential life support systems of the planet-and urge action to prevent it.Current nuclear arms control and nonproliferation efforts are inadequate to protect the world's population against the threat of nuclear war by design, error, or miscalculation. The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) commits each of the 190 participating nations "to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control." 4 Progress has been disappointingly slow and the most recent NPT review conference in 2022 ended without an agreed statement. 5 There are many examples of near disasters that have exposed the risks of depending on nuclear deterrence for the indefinite future. 6 Modernization of nuclear arsenals could increase risks: for example, hypersonic missiles decrease the time available to distinguish between an attack and a false alarm, increasing the likelihood of rapid escalation.Any use of nuclear weapons would be catastrophic for humanity. Even a "limited" nuclear war involving only 250 of the 13 000 nuclear weapons in the world could kill 120 million people outright and cause global climate disruption leading to a nuclear famine, putting 2 billion people at risk. 7,8 A large-scale nuclear war between the US and Russia could kill 200 million people or more in the near term, and potentially cause a global "nuclear winter" that could kill 5 to 6 billion people, threatening the survival of humanity. 7,8 Once a nuclear weapon is detonated, escalation to all-out nuclear war could occur rapidly. The prevention of any use of nuclear weapons is therefore an urgent public health priority and fundamental steps must also be taken to address the root cause of the problem-by abolishing nuclear weapons.The health community has had a crucial role in efforts to reduce the risk of nuclear war and must continue to do so in the future. 9 In the 1980s the efforts of health professionals, led by the International Physicians for the Prevention of Nuclear Opinion EDITORIAL