Nuclear Conflict Escalation

The most probable existential threat stems from a miscalculated escalation of a major geopolitical conflict into full-scale nuclear war. Current trends show a dangerous erosion of arms control treaties, the integration of AI into military command and control (increasing decision speed and uncertainty), and the resurgence of great-power competition. The risk is not from a single act, but from a cascade of failures in deterrence, communication, and crisis management, triggered by a regional conflict that draws in nuclear-armed states. The ensuing exchange would directly kill hundreds of millions, with the subsequent "nuclear winter" (global climate disruption from soot and smoke) causing a collapse of agriculture and leading to the starvation of most of humanity.