It was a doomsday scenario built around one of Earth’s most powerful volcanic systems.
UK scientists have outlined an apocalyptic timeline describing what could happen if the Yellowstone supervolcano were to erupt on a massive scale.
“A super-eruption on this scale would be a threat to civilization as we know it,” the researchers wrote in a recent article for The Conversation.
The volcanic system lies beneath the 30-by-45-mile Yellowstone Caldera and is among the most closely monitored geological formations on the planet. Scientists define a supereruption as an event that ejects more than 230 cubic miles of magma, rock and ash.
Yellowstone has produced three such eruptions over the past 2.1 million years, the most recent occurring 631,000 years ago. That event killed all life within hundreds of miles, spread ash across North America and triggered consequences that were felt around the globe.
Human ancestors had not yet reached North America at the time, so no people witnessed the disaster. Scientists warn, however, that a future eruption could pose a grave threat to modern civilization.
To estimate the potential devastation, the researchers examined how nations have responded to major disasters in recent decades. The team was led by Ilan Kelman, a disasters professor at University College London, and Matthew Blackett, a reader in physical geography and natural hazards at Coventry University.
“What follows is a thought experiment into what might happen in the worst-case scenario,” they wrote.
About one month before the eruption, seismologists would detect a sharp rise in earthquakes, prompting officials to move the volcano alert level from “normal” to “advisory.”
Three weeks before the projected eruption, the unrest would intensify. Earthquakes would become shallower, while geysers and other hydrothermal features grew increasingly unpredictable.
A week later, experts would announce an 85% to 92% chance of a catastrophic eruption within three weeks, raising the alert level to “watch.”
Authorities would also establish an evacuation zone extending 62 miles, or 100 kilometers, beyond Yellowstone National Park. The area would encompass roughly 200,000 residents, many of whom would flee across international borders.
On eruption day, magma would enter Yellowstone’s hydrothermal system, blasting “superheated steam, mud and shattered blocks of rock” miles into the sky. Hours later, gas-rich magma would break through the surface, producing an enormous eruption column that could rise 31 miles, or 50 kilometers, into the atmosphere.
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Deadly currents of searing gas, ash and rock would race across the landscape, killing as many as 1,000 people immediately. Farmland across several states would be destroyed, while electricity and water infrastructure suffered widespread disruption.
Within three days to a week, much of North America would be plunged into darkness. Billings, Montana, could be buried beneath three feet of ash, as supply chains, sewage networks, heating systems and mobile phone services began to fail.
After two weeks, ash would clog roads, overwhelm drainage systems and force the closure of airports, railways and farms. The US, Canada, Mexico and most Caribbean and Central American nations would declare states of emergency.
Four to six months later, respiratory illnesses would place hospitals under enormous pressure. Damage to North American agriculture would also send food prices soaring worldwide.
Combined with a banking crisis, those disruptions would push the global economy into recession.
A decade after the eruption, people around the world would have adopted a more agrarian way of life, while those still eating meat would increasingly depend on hunting. Even so, widespread starvation and mass migration would remain unavoidable features of the crisis.
The researchers estimate that, after the immediate destruction and long-term consequences were taken into account, “there could be 0.7-1.3 billion premature deaths due to the eruption and its impacts.”
The one silver lining is that in the past, “this unstoppable power of volcanism changed the planet, but did not end humanity – or come close to doing so.”
Thankfully, a Yellowstone eruption isn’t eminent by any means. Based on the prior three eruptions, there has been an average of around 725,000 between events, meaning we technically have 100,000 years to go before the next one.
And, as the USGS experts pointed out, “this is based on the average of just two time intervals between the eruptions, which is meaningless.”
Plus, even if the caldera does go off again, it might not even be large as the most recent volcanic eruption at Yellowstone, “a lava flow that occurred 70,000 years ago.”
Nonetheless, they point out that “volcanoes do not work in predictable ways and their eruptions do not follow predictable schedules.”