The hypothetical eruption would devastate areas within hundreds of kilometers of Yellowstone, with pyroclastic flows, ashfall, and infrastructure collapse. Immediate casualties could reach thousands, with long-term health impacts from ash inhalation and water contamination. Globally, the eruption could disrupt agriculture, transportation, and economies, leading to food shortages and a potential global recession. Sulfate aerosols in the atmosphere could cause a temporary cooling effect, altering weather patterns and impacting ecosystems worldwide.