6 dangerous volcanoes that could shut down the world

Alaska's Mount Spurr volcano is close to erupting, according to scientists. The volcano is "releasing unusual levels of volcanic gases near its summit and from a flank vent that last erupted in 1992," said Live Science. An eruption would cause aviation disruption along with ashfall. Luckily, the area around the volcano is large and uninhabited.

While Mount Spurr does not spell the end of the world, other volcanoes around the world do have the potential to cause catastrophic damage. In addition, climate change may be increasing the risk of volcanic eruptions because the "tremendous weight of glaciers and ice sheets can tamp down volcanoes," said Reuters. "When the ice retreats, the downward pressure on the planet's thin outer crust and much thicker underlying mantle eases, allowing the ground to rebound," and this causes "volcanoes to produce more magma and alter its movement, influencing eruptions."

Scientists have been monitoring several supervolcanoes that have the potential to cause widespread or even apocalyptic damage. Here are six of them.

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1. Campi Flegrei (Italy)

Last eruption: 1538

Effects of a major eruption: Located just east of Naples, Campi Flegrei is not just a single volcano, but a volcanic system containing 24 craters. If it were to erupt, it could "cover Naples and surrounding areas in ash, trigger earthquakes and landslides throughout southern Italy as well as cause widespread air pollution and acid rain," said Wanted in Rome. Campi Flegrei's largest eruption occurred 36,000 years ago and "pumped ash across the Mediterranean region and spawned a bitter volcanic winter across eastern Europe, with temperatures reduced by up to 9°C (16.2°F)," said the BBC.

Likelihood: Campi Flegrei experienced a 4.4-magnitude earthquake in March 2025, however, there has been "no type of process that gives us a sign of imminent eruption," Francesca Bianco, the director of the Vesuvius Observatory, said to Wanted in Rome. "For this to happen, magma must rise to the surface and this is not happening." The bad news is that Italy is ripe with volcanic activity.

2. Mt. Vesuvius (Italy)

Last eruption: 1944

Effects of major eruption: Also in Italy and famous for wiping out Pompeii and Herculaneum in 79 A.D., Vesuvius would do much greater damage if it erupted again today. "Given its potential, Vesuvius could endanger more than 3 million people and wipe out the city of Naples," said HowStuffWorks. The region also has a "'squatter' dilemma, with over 700,000 people residing illegally on its slopes," at risk. Vesuvius' next eruption will likely be an "incredibly forceful explosion … marked by flying rock and ash at speeds of up to almost 100 miles per hour."

Likelihood: Scientists say Vesuvius likely won't have a major eruption again for a few hundred years.

3.. Cumbre Vieja (La Palma, Canary Islands)

Last eruption: 2021

Effects of a major eruption: When Cumbre Vieja last erupted in 2021, "lava poured out of the volcanic ridge, and flowed to the sea, engulfing 3000+ dwellings, said NASA's Jet Propulsion Laboratory. While thousands of people were evacuated, the damage from the eruption was not as severe as it could have been. Scientists had warned that a major eruption of Cumbre Vieja could cause the entire western flank of the volcano to fall into the sea, creating a "mega-tsunami" wherein "waves hundreds of meters high" would radiate "out into the Atlantic," the New Zealand Herald said. However, subsequent studies of the "potential consequences of a collapse at Cumbre Vieja have significantly downplayed the risk" of such an outcome. In a 2021 report for the U.S. Geological Survey, the Hawaiian Volcano Observatory said that the theory of an eruption-prompted mega-tsunami "does not hold up to rigorous examination."

Likelihood: Scientists say the "year to year probability" of a major eruption is low, but preparations should be taken anyway given the potentially cataclysmic damage.

4. Mount St. Helens (Washington, United States)

Last eruption: 1980

Effects of major eruption: Mount St. Helens' eruption in May 1980 resulted in 57 deaths and caused the "largest landslide in recorded history," said NASA. In addition, "hot pressurized magma erupted, and the ash plume reached a towering height of 80,000 feet (15 miles, 24 km), before blanketing the surrounding region," said EarthSky. Everything within approximately 230 square miles was destroyed and required extensive recovery. "In the decades since the eruption, Mt. St. Helens has given scientists an unprecedented opportunity to witness the intricate steps through which life reclaims a devastated landscape," NASA added.

Likelihood: While Mount St. Helens is expected to erupt again in our lifetimes, "neither a large debris avalanche nor a major lateral blast like those of May 18, 1980 is likely now that a deep crater has formed," said the U.S. Geological Survey.

5. Popocatépetl (Mexico)

Last eruption: Ongoing since the early 2000s

Effects of a major eruption: The third-tallest active volcano in the Northern Hemisphere, Popocatépetl is only 40 miles west of Mexico City, whose metropolitan area has an estimated 22 million inhabitants, and just 30 miles east of Puebla, a city of around six million. A large eruption could send "a city-sized cloud of ash 20 centimeters thick" to "descend upon the buildings of Mexico City," Pacific Standard said. The deadly cloud would then "clog Mexico City's drainage lines, poisoning its water supplies and ceasing electricity transmission via short-circuiting," and the devastation would be accompanied by "1,000-degree lahars and pyroclastic flows" that would reach most of the towns in the immediate area.

Likelihood: After an 80-year dormant period, Popocatépetl has had recurring seismic activity for years, with 13 eruptions occurring as recently as February 2024. While small explosions have caused alarm, "after nearby towns were coated in ash," The Associated Press said, "volcanologists called the activity 'nothing new or surprising.'"

6. Yellowstone Supervolcano (Wyoming, United States)

Last eruption: 640,000 years ago

Effects of a major eruption: When the Yellowstone Caldera, or "supervolcano," in Yellowstone National Park erupts again, "its effects would be worldwide," the U.S. Geographical Survey said. In the U.S., the closest states to Yellowstone, including Montana, Idaho and Wyoming, could be "affected by destructive pyroclastic flows, which are a mix of lava blocks, pumice, ash and volcanic gas that flows around a volcano after an eruption," said The Hill. "Much of the rest of the country could be blanketed in falling volcanic ash — in some places, it could be more than three feet deep." Globally, the volcano could also "impact the global climate by emitting ash and gas into the stratosphere, which could block sunlight and lower global temperatures for a few years," Michael Poland from the Yellowstone Volcano Observatory said to LiveScience. The resulting catastrophe could "shut down transportation, collapse buildings, short-out the electrical grid and cause massive agricultural failure," the University of British Columbia's Johan Gilchrist said to CBC Radio.

Likelihood: While there is a lot of anticipation, "scientists revealed that Yellowstone National Park likely won't experience a supervolcano eruption within the same timeframe they once believed," as new research has found less concentrated magma than previously thought, said VICE.