Nuclear Proliferation and Escalation Risk

Nine states hold roughly 12,000 nuclear warheads. Nearly every major arms control treaty has lapsed or been suspended, arsenals are being modernised and in some cases expanded, and nuclear rhetoric has re-entered active conflicts. The expected death toll today is zero, but the tail risk is uniquely catastrophic: a regional exchange is modelled to cause tens of millions of immediate deaths and a global famine killing billions through soot-driven cooling. It is included here as the clearest example of an event where present impact and potential impact diverge enormously.