Climate Collapse

The most probable cause is the cascading and irreversible collapse of Earth's climate systems. While geopolitical conflict or AI risk are significant, they are more likely to be catalyzed or severely exacerbated by climate-driven destabilization. Accelerating feedback loops—such as permafrost thaw releasing methane, ice loss reducing albedo, and Amazon dieback altering rainfall—are pushing global temperatures toward irreversible tipping points much faster than predicted.

This triggers systemic collapse through interconnected crises: catastrophic failure of global agriculture leading to mass famine, overwhelming heat stress making regions uninhabitable, accelerating sea-level rise displacing billions, and the collapse of vital ecosystems like fisheries. These pressures overwhelm international cooperation, driving resource wars, mass migration, and the breakdown of nation-states. The result is not a single event, but a rapid, unmanageable decline in global complexity and population, rendering modern civilization unsustainable.