Ending the Nuclear Threat
Nine countries together own about 12,000 nuclear weapons, and a war using many of them would harm the whole planet. For decades, treaties limited how many each side could keep and inspectors could visit and count. Those agreements have been running out, and the last one between the US and Russia ended in February 2026. Nobody has found a way to prove that a bomb is real, or that it was destroyed, without showing the secret of how it works. Until checks that all sides trust exist, deep cuts stay a hope.
Open in the interactive tree →Global stockpiles peaked at about 70,300 warheads in 1986 and fell to roughly 12,200 by 2026, mostly through US and Russian dismantling. Arms-control treaties that capped and inspected arsenals have lapsed one by one: the INF Treaty after the US exit in 2019, New START inspections from 2020 and New START itself in February 2026. The Comprehensive Nuclear-Test-Ban Treaty (1996) is still not in force, and no nuclear-armed state has joined the 2021 treaty banning nuclear weapons.
As of now
SIPRI estimated 12,187 warheads in January 2026, of which 9,745 were in military stockpiles and about 4,012 deployed; 2,100-2,200 sat on high-alert missiles. SIPRI expects the long decline to reverse as dismantling slows and new weapons are deployed, with China (about 620 warheads) growing fastest. New START, which capped each side at 1,550 deployed strategic warheads, expired on 5 February 2026; the US declined Russia's offer to keep the limits for another year, Russia says it will observe them only while the US does, and China refuses to join talks. A zero-knowledge neutron protocol proposed in Nature in 2014 shows how a warhead could be checked without revealing its design, but no real warhead has been tested this way.
What is missing
- A method to verify that an object is a real warhead, and that it was dismantled, without revealing its design
- An arrangement that covers all nine nuclear-armed states and not only the US and Russia
- A treaty ending the production of weapons-usable uranium and plutonium (proposed since 1993, never negotiated)
- Safeguards against false alarms and against automated systems taking part in launch decisions
Becomes possible once solved
- Verified deep cuts in nuclear arsenals
- A lower risk of a launch caused by a false alarm or a misjudged crisis
- Progress on the stalled test-ban and fissile-material talks
- A basis for checking limits on new types of weapons
Open steps
- Checking a Warhead Blind Medium AI leverageConfirm that an object is a real warhead of the declared type without recording any design information, using information barriers or a physical zero-knowledge protocol.
- Proving a Warhead Dismantling Low AI leverageShow that a declared warhead was taken apart and its material accounted for, with an unbroken chain of custody from the weapon to the storage site, without revealing design details.
- Counting Fissile Material Medium AI leverageTrack how much weapons-usable uranium and plutonium states produce and hold, the basis of a treaty to end production that was proposed in 1993 and never negotiated.
- Detecting Hidden Nuclear Tests Medium AI leverageTell a secret underground or low-yield nuclear test from earthquakes, mine blasts and other events, using seismic, hydroacoustic, infrasound and radionuclide data.
- Safe Nuclear Launch Decisions Low AI leverageStop false alarms and automation from triggering a nuclear launch: keep people in the decision, give them time and trustworthy warning data, and set rules for AI in command and control.
Where today's AI could help
Low AI leverage. The main obstacle is political trust between states, though models can speed up test detection, imagery analysis and protocol design.
- classify seismic events as explosions or earthquakes
- flag changes at known nuclear sites in satellite images
- simulate neutron measurements and attacks on warhead-checking protocols
Shown so far
- At the CTBTO Science and Technology Conference (June 2023), researchers presented machine-learning classifiers that separate underground nuclear explosions from earthquakes using monitoring-network data. source
- Idaho National Laboratory (2022) reviewed machine learning on public satellite images to detect scene changes at nuclear fuel-cycle sites, aimed at helping the IAEA find undeclared facilities. source
Prerequisites
- Seismology: Inside the Earth1906Seismic networks are the main tool for spotting secret tests.
- Manhattan Project1942-1945Today's arsenals descend from the weapons the Manhattan Project first built.
- Game Theory1944Deterrence and arms races are strategic games with rival players.
- Nuclear Non-Proliferation Treaty1968The treaty frame for non-proliferation and the duty to disarm.
Unlocks
- Verified Nuclear Disarmament2050s?Needs trusted ways to check warheads, stocks and tests.