Nuclear War

A large-scale nuclear exchange between major powers remains the most probable near-term existential threat. Current geopolitical tensions—particularly among nuclear-armed states like the U.S., Russia, and China—create conditions for both intentional and accidental escalation. Even a "limited" exchange (e.g., between India and Pakistan) could unleash sufficient soot into the atmosphere to trigger nuclear winter, collapsing global agriculture and rendering Earth largely uninhabitable.

Existing arsenals (over 12,000 warheads worldwide) ensure catastrophic yield, while AI-driven misinformation and eroded diplomatic safeguards heighten risks of miscalculation. Though climate collapse and AI risks are severe, they lack the immediate, civilization-ending destructive power of nuclear conflict. The probability of human extinction from this single mechanism exceeds that of all other natural or anthropogenic threats combined.