Climate Collapse

The most likely world-ending scenario is a cascading climate collapse, driven by unchecked greenhouse gas emissions. This isn't a singular event but a convergence of tipping points—such as the irreversible loss of polar ice sheets, the die-off of coral reefs, and the destabilization of major weather patterns like the jet stream. These would trigger runaway feedback loops, making large regions of the planet uninhabitable due to extreme heat, chronic drought, and catastrophic sea-level rise.

The ensuing breakdown of global agriculture would lead to mass famine and societal collapse. This resource scarcity would intensify geopolitical conflicts, mass migration, and wars, further straining international cooperation. The combination of environmental breakdown and human conflict would create a feedback loop of instability from which complex global civilization cannot recover, ultimately threatening human extinction.