Climate Collapse

Based on accelerating global trends, the most likely world-ending scenario is a cascading climate collapse driven by unchecked environmental degradation. Rising temperatures, fueled by greenhouse gas emissions, are already intensifying extreme weather events, sea-level rise, and biodiversity loss. By mid-century, tipping points like melting permafrost and collapsing ice sheets could release massive methane stores, amplifying warming beyond human control.

This would lead to widespread crop failures, mass migrations, and resource wars, straining geopolitics and society. Technological fixes like geoengineering may exacerbate issues through unintended consequences, while societal denial and political inaction hinder mitigation. Ultimately, this could render large parts of Earth uninhabitable, causing societal breakdown and potential human extinction over decades, outpacing other risks like nuclear conflict or AI mishaps in probability.