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Nuclear Weapons

Almost eighty years after their introduction, the risks posed by nuclear weapons are as high as ever - and new research reveals that the impacts are even worse than previously reckoned.

There are an estimated 13,000 nuclear weapons in the world, distributed unevenly among nine states. Some of them are hundreds of times more powerful than those which destroyed Hiroshima and Nagasaki. The use of just a few hundred could leave Earth’s population decimated by a nuclear winter.

The risks of nuclear weapons range from nuclear terrorism, or a ‘tactical nuclear’ attack on a single city, which could kill millions of people, to global nuclear war, which could kill billions. Notably, the latter has almost happened many times by accident. The potential impacts of these risks are countless; many are still unexplored. A 1979 report estimated, based on initial blasts, radiation risks, power grid disruption and more, that 28-88% Americans and 22-50% Soviets would die. That was before nuclear winter was discovered.

In the 1980s, researchers saw that a nuclear war could cause vast amounts of smoke to spread around the globe, blocking out sunlight and transforming summers into winters, much as asteroids or supervolcanoes did in the past, causing mass extinctions. Today’s more sophisticated climate models show that 1980s research underestimated this impact. In several core farming regions, climate models show temperatures will reduce by 20°C for several summers, and by about half ten years later. The world as we know it would crumble, due to starvation, hypothermia, and epidemics.

Even if just one superpower launched its full nuclear arsenal against the other without retaliation, nuclear winter would still ensure the attacking country’s self-destruction. This realisation helped motivate the ‘nuclear freeze’ movement following the Cold War, which saw a 75% reduction of global nuclear stockpiles. But despite the Non-Proliferation Treaty’s pledge to disarm, progress has dwindled. The nuclear freeze is thawing.

The design and production of new nuclear weapons are not only unnecessary for deterrence, but actually make accidental war more likely. As well as encouraging states to develop nuclear weapons, it gives terrorists better access to enrichment materials.

FLI thus opposes such development, as well as weapons testing. We also encourage steps to reduce the tremendous risk of nuclear winter: this includes de-escalation from tense war scenarios – when near-misses have disproportionately occurred – and smaller steps like the removal of weapons from ‘hair-trigger’ alert.

Looking to recent developments, we also stand firmly against efforts to incorporate Artificial Intelligence systems into nuclear weapons controls. Such an incorporation raises the possibility of catastrophic miscalculations and blunders by speeding up response times, and excluding the human intuition and hesitation which have many times helped avert World War III.

Mushroom cloud from the nuclear bomb dropped on Nagasaki

Recommended reading

The Risk of Nuclear Weapons

Despite the end of the Cold War over two decades ago, humanity still has ~13,000 nuclear weapons on hair-trigger alert. If detonated, they may cause a decades-long nuclear winter that could kill most people on Earth. Yet the superpowers plan to invest trillions upgrading their nuclear arsenals.
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Recent content on Nuclear Weapons


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US Nuclear Targets

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Open letters


Open letter calling on world leaders to show long-view leadership on existential threats

The Elders, Future of Life Institute and a diverse range of co-signatories call on decision-makers to urgently address the ongoing impact and escalating risks of the climate crisis, pandemics, nuclear weapons, and ungoverned AI.
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UN Ban on Nuclear Weapons Open Letter

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