Scientists Outline Potential Global Impacts of a Yellowstone Supervolcano Eruption
Researchers explain how a future eruption of Yellowstone could produce massive ash fallout, trigger a brief global cooling period and cause widespread indirect fatalities, while noting that extensive monitoring would likely provide early warning.
The Yellowstone caldera, a supervolcano located in the western United States, has not erupted for more than 600,000 years, but scientists say a future eruption could have far-reaching consequences. A supervolcano is defined by its ability to eject at least 1,000 cubic kilometres of material in a single event, a scale far beyond historic eruptions such as Mount St. Helens.
Yellowstone is one of three U.S. supervolcanoes, alongside Long Valley and Valles calderas. According to the United States Geological Survey, only a small fraction of its rhyolite magma reservoir is currently molten, making an imminent eruption unlikely. Nevertheless, researchers from University College London and Coventry University have modeled a plausible scenario in which the volcano awakens.
"If small earthquake swarms migrate upward and satellite data show accelerating uplift, scientists would interpret these signs as increasing probability of an eruption," the authors wrote in a paper for The Conversation.
Monitoring networks would likely detect such precursors weeks before a major eruption, allowing authorities to implement evacuation and response plans coordinated by the Yellowstone Volcano Observatory. Initial fatalities could be limited, but ash fallout would be extensive. Cities in the United States and Canada could be buried under several feet of ash, disrupting power grids, transportation and water supplies.
The injection of large quantities of sulfur-dioxide-rich ash into the stratosphere would reflect sunlight, producing a temporary global cooling of about 1.5 °C. Crop failures in North America could drive up food prices worldwide, and the authors estimate that indirect deaths could reach hundreds of millions over the following decade, with additional premature mortality from air-quality impacts.
While the authors conclude that humanity would ultimately survive such an event, they stress that the societal and environmental effects would be profound and lasting.