Nuclear War

The convergence of escalating geopolitical rivalries, climate-driven resource conflicts, and the integration of unchecked AI into nuclear command systems makes a civilization-ending nuclear exchange the most probable global catastrophe. Heightened mistrust between major powers, erosion of arms-control treaties, and the proliferation of tactical nuclear weapons lower the threshold for use. Simultaneously, AI-assisted early-warning and decision-making loops increase the risk of rapid, irreversible escalation based on false alarms or algorithmic miscalculation. Once triggered, even a limited nuclear war would loft enough soot into the stratosphere to cause a severe nuclear winter, disrupting global agriculture and leading to mass starvation, which would compound the immediate blast and radiation fatalities. This chain reaction would collapse interconnected economic, energy, and information networks, making recovery impossible and ending organized human society within a decade.