The chance of accidental nuclear war has been going down

Link post


  • I find there have been ten accidental nuclear incidents in history where I think there was some non-negligble chance that, had things played out differently, there could’ve been a nuclear exchange.

  • I think the chance of another accidental nuclear incident happening in the next decade (2022-2032) is ~28%. I take a ~5% chance that any given incident will escalate into a nuclear exchange causing at least one fatality[1], putting the chance of an accidental nuclear exchange in the next decade at ~2%.

  • By combining my estimates here with other averages of expert forecasts, I think the overall chance of nuclear exchange (intentional or unintentional) this decade is ~6%.

  • The 1960s represented a high point in the risk of accidental nuclear exchange. The number of incidents has gone down significantly since 1960 and has gone down significantly again after the 1990s, with no such incidents occuring since 1995.

  • Better technology to reduce false positives has likely reduced the risk of accidental nuclear exchange. Many past incidents were the result of computer errors detecting weather or other peaceful events as nuclear launches and these seem less likely to happen now.

  • More time spent between the development of offensive nuclear weapons and now without observing an incident should gradually over time reduce our chance that such an incident will occur in the future, all else being equal. This makes the risk higher in the past than the future, all else being equal.

  • Thanks to international arms control agreements, we have moved from a height of over 63,000 nuclear weapons in the 1980s to under 14,000 nuclear weapons today. This also, all else being equal, reduces risk and shows that progress is possible.

  • We also have much more geopolitical peace since the end of the Cold War and this has likely reduced the chance of accidental nuclear war. But it’s possible this era of peace is backsliding given recent tensions with Russia (and also China).

This is a link post for my new blog, so read the rest there!