Will a nuclear weapon be used (intentionally in an attack/war, or accidentally via unauthorized launch or detonation) anywhere in the world between now and December 31, 2100?

probability: 41%

rationale:

The probability of a non-test nuclear detonation occurring by the end of 2100 is 41%.

Initial baseline hazard and geopolitical parameters are validated. The 81-year historical non-use streak establishes a strong downward anchor, but the structural degradation of arms control—most notably the expiration of New START without a successor 2 sources—creates significant, compounding upward pressure over a 74-year horizon. The Doomsday Clock standing at 85 seconds to midnight further underscores this systemic fragility thebulletin.org.

Global nuclear arsenals remain at roughly 12,187 warheads with over 2,100 on high operational alert 2 sources, maintaining immense physical exposure. Upward risk is currently driven by active, multipolar escalation pathways. Evidence points to persistent nuclear signaling in the Russia-Ukraine conflict 2 sources, escalating deterrence challenges in South Asia following the severe 2025 India-Pakistan crisis 2 sources, and intensifying proliferation pressures involving Iran, China, and North Korea 3 sources.

Furthermore, the target criteria capture not just intentional strategic exchanges but single tactical, terrorist, accidental, or unauthorized detonations. Advancements in autonomous systems and the integration of artificial intelligence into nuclear command, control, and early-warning operations introduce deep structural uncertainties 2 sources. As historical close calls like the 1983 Petrov incident [ccee4fa] demonstrate, the risk of miscalculation is non-negligible. Escalation pathways involving dual-capable systems or cyber-nuclear entanglement heavily exacerbate these vulnerabilities 2 sources.

Projecting these dynamics forward, the compounding mathematics of even a low annual risk are inescapable. Balancing the proven resilience of the nuclear taboo and established deterrence mechanisms against the current geopolitical deterioration and the broad definition of a qualifying event requires an average annual hazard rate of approximately 0.7%. Over the remaining ~74 years of the century, this constant hazard mathematically resolves to a 41% cumulative probability of at least one yield-producing detonation.