Nuclear War

Rising geopolitical tensions, nuclear proliferation, and the erosion of arms control agreements significantly heighten the risk of nuclear conflict. A large-scale exchange could trigger nuclear winter, collapsing global agriculture and leading to mass starvation. Even a "limited" strike risks uncontrollable escalation. The presence of thousands of warheads, combined with miscalculation or intentional use in crisis, makes this the most probable existential threat in the near term.