Climate Catastrophe

Based on accelerating global trends, the most likely world-ending scenario is a cascading climate catastrophe driven by unchecked environmental degradation. Rising temperatures, fueled by greenhouse gas emissions, are already causing extreme weather events, sea-level rise, and biodiversity loss. By mid-century, these could trigger tipping points like the collapse of major ice sheets and permafrost thaw, releasing massive methane stores and amplifying warming.

Geopolitically, resource scarcity from droughts and crop failures would exacerbate conflicts over water and arable land, potentially leading to mass migrations and societal breakdowns. Technologically, while renewable energy advances offer mitigation, current adoption rates lag behind the pace of damage, and societal denialism hinders global cooperation. This could culminate in widespread famine, disease outbreaks, and civilizational collapse, rendering large parts of the planet uninhabitable without directly causing instant extinction but effectively ending human society as we know it.