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Is climate change lighting a fuse under Iceland's volcanoes?

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Reuters

Toxic sulfurous gas, carrying the telltale reek of rotten eggs, wafted through vents in the steep walls of Iceland’s Viti crater, while carbon dioxide bubbled to the surface of the milky blue crater lake. Veils of steam wreathed the landscape of loose rock in eerie half-light.Through this forbidding terrain – “Viti” is derived from the Icelandic for “hell” – Michelle Parks, a volcanologist with the Icelandic Meteorological Office, picked her way toward the water’s edge one day last August. With a monitor strapped to her hip to warn her if the gases reached dangerous levels, she stooped to submerge a temperature probe in the lake – 26.4 degrees Celsius (79.5 degrees Fahrenheit), consistent with recent readings.That was reassuring, at least for the time being. The crater was formed when Askja, a volcano in Vatnajokull National Park in Iceland’s central highlands, uncorked in an explosive eruption in 1875. Askja’s last eruption, in 1961, was milder, and for decades after, the volcano was quiet. But in 2021, Parks and other scientists keeping tabs on it were shocked to find that in just a few months, the volcano had rapidly expanded, uplifting by 11 centimeters (4.3 inches). This phenomenon, called inflation, occurs when magma or pressurized gases accumulate under a volcano, pushing the ground upwards and outwards.In the three years since, Askja’s bloat has reached about 80 cm (32 inches). That uplift, scientists estimate, is the result of 44 million cubic meters (1.6 billion cubic feet) of magma flowing into the existing reservoir around three km (two miles) beneath the surface.Volcanologists have established a correlation between magma buildup under a volcano and subsequent eruption. But they don’t know exactly how much magma is needed to help trip an eruption. That is why Parks and her colleagues are closely monitoring the temperature and acidity of Viti’s crater lake. A jump in either, indicating that more gases are pushing in from below, would suggest the volcano is moving closer to an eruption. So far, those metrics have remained stable, but the scientists watching Askja don’t take that for granted.An eruption could be catastrophic, though smaller ones are much more likely. On the scale volcanologists use to measure the size of explosive eruptions, Askja is capable of one equivalent to that of Mount St. Helens in the U.S. state of Washington in 1980, although its eruptive style would differ. That eruption, which sparked the Australia-born Parks’ lifelong passion for volcanoes, unleashed a force equivalent to 25,000 Hiroshima-type atomic bombs.The aim of the volcano observatory at the Icelandic Meteorological Office is to monitor the country’s volcanoes for changes in activity, like those now observed at Askja, helping to protect the nation’s nearly 400,000 citizens and the hordes of foreign tourists who visit every year to enjoy Iceland’s world-renowned geothermal attractions.However, the team’s work has taken on broader significance. Last year, Parks and colleagues with the University of Iceland received government funding for a pioneering research project across 12 institutions to test a theory that could have dire implications not just for Iceland, but for every person on the planet: Whether the rapid retreat of glaciers as a result of human-caused climate change will trigger increased volcanic activity.The basic process underpinning the idea is simple. The tremendous weight of glaciers and ice sheets can tamp down volcanoes. 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. This change in pressure spurs dynamic forces beneath volcanoes to produce more magma and alter its movement, influencing eruptions.What scientists already know of Iceland’s eruptive history supports the theory. When the thick glaciers and ice caps that had covered the North Atlantic island during the last major Ice Age receded between about 15,000 and 10,000 years ago, underlying volcanoes responded with fury. In 2002, scientists calculated changes in Iceland’s volcanic activity over time by analyzing the chemical composition of lava rock samples. They found that eruption rates surged an estimated 30 to 50 times during and shortly after the ice loss compared to the preceding Ice Age and recent times. Parks said it would likely be a cataclysmic scenario, with a &#x27;ridiculous amount of eruptions&#x27;. Askja, too, registered a major explosive eruption during this time.Once again, scientists say, the elements needed to set off another surge in eruptions are converging. Glaciers now cover just 10% of Iceland, but that ice still weighs on more than half the nation’s 34 active volcanic systems, and it is rapidly melting as global temperatures climb. In the past 130 years, Iceland’s glaciers have lost about 16% of their volume, with half of that in just the past three decades. Scientists predict roughly half of the remaining volume will be gone by this century’s end.Already, the magma chambers beneath Iceland may be responding to the loss of ice, and not just those directly under glaciers. Askja, which has been free of ice for 10,000 years, and much of Iceland are rebounding because pressure changes from glacial retreat affects large parts of the Earth’s crust and mantle.Over the last three decades, magma has been produced beneath Iceland at a rate 2 to 3 times what it would have been without the ice loss, according to preliminary modeling results from Parks’ project shared exclusively with Reuters. Parks said more magma was coming in underneath Iceland, and they just didn&#x27;t need it as had enough already.Scientists first theorized in the 1970s that melting ice might impact volcanic eruptions. But only recently have they begun to understand the scale of the potential threat.University of Iceland volcanologist Freysteinn Sigmundsson has been coming to Askja almost every year since 1990 and he knows the terrain well. Shouldering a surveying tripod, he clambered with sure-footed expertise across beds of jagged, crunchy lava, searching for round metal markers that scientists anchored in the area in the 1960s and 1970s. These would tell him where to set up his equipment to check how much Askja had grown or shifted over the past year.The measurements Sigmundsson and his colleagues took in August showed 12 cm (five inches) of uplift at Askja since the previous year, confirming that the volcano was still in a state of unrest and could erupt at any time.The Icelandic government has emergency plans in place for a Katla-style eruption and works with local police districts to create near-term risk assessments for other volcanoes. But after the Eyjafjallajökull eruption, the Icelandic government made volcanoes a pillar of a now multibillion-dollar tourism industry. Souvenir shops in the capital, Reykjavik, sell lava rocks from a recent eruption on the Reykjanes Peninsula for 2,000 Icelandic krona (US$14) apiece.Like many Icelanders, 29-year-old Iris Ragnarsdottir Pedersen and her father, 62-year-old Ragnar Frank Kristjansson, have an intimate knowledge of the extremes of their land of ice and fire. Along the south coast in Svinafell, Ragnarsdottir Pedersen, a mountain guide, lives with her husband and their Icelandic sheepdog, Blika. Her father, a retired national park manager, has a small turf-roofed summer house next door. Towering over them is a large cliff, beyond which lies Vatnajokull ice cap and, under it, the volcano Oraefajokull. After Oraefajokull erupted in 1362, sailors reported seaborne pumice floating “in such masses that ships could hardly make their way through it.”Father and daughter both recall joining fellow Icelanders over the years to marvel at the glowing fountains and rivers of lava produced by eruptions. They also are familiar with the impact of climate change. For 25 years, Kristjansson has volunteered as a glacier monitor with the Icelandic Glaciological Society, tracking the retreat of two glaciers that flow out of the Vatnajokull ice cap, the nation’s largest. Every autumn, he treks for hours to one of the glaciers, Skeidararjokull, to take measurements that he sends to the Icelandic Meteorological Office. “It&#x27;s a lonely walk toward the glacier — 15 km in the black sand,” he said.Kristjansson used to be able to stride right up to the edge of Skeidararjokull. But as it has rapidly shrunk over the past decade, a lake has formed at the foot of the glacier, blocking his way. He now has to use special binoculars to measure the distance. This year, he said, one point along the glacier’s edge showed a retreat of 300 meters (984 feet), which is the greatest he has recorded.Ragnarsdottir Pedersen has witnessed the retreat from year to year on treks to the glaciers with her father and by simply looking out her windows. “It’s just devastating to see,” she said. “I’ve sometimes said to people, ‘It’s like watching your friends disappear.’ ”As a child, she knew Oraefajokull lurked under the Vatnajokull ice cap. But it only became a concern when the volcano started rumbling in 2017, just as she and her husband began planning to build their home near it. When she felt the earthquakes and caught the smell of sulfur from the rivers, she said it brought it home, literally, that they live on a &#x27;dangerous volcano.’So few people make their home near Askja. The closest village lies about 60 km (37 miles) away. But some 13,000 people visit the volcano during the summer months, when Askja is more accessible, according to data from the national park authority. Often, tourists climb down into Viti crater to swim in the Instagram-worthy lake, despite signs that warn them about acidic water, which can irritate skin, and falling rock.One of the greatest risks to tourists is a phreatic explosion — a blast of hot steam, ash and rocks that comes with little warning. That’s what formed Viti crater nearly 150 years ago. In 2019, a phreatic explosion at New Zealand’s White Island volcano killed 22 people who were visiting the island at the time.Regardless of what the scientists there ultimately find, the interplay between volcanoes and ice will remain a chief worry among volcanologists. But the small number of studies to date of the interaction between retreating ice and volcanoes in other parts of the world, scientists said, mean the research underway in Iceland will help create a template for what could happen elsewhere. -Report from Reuters

Toxic sulfurous gas, carrying the telltale reek of rotten eggs, wafted through vents in the steep walls of Iceland’s Viti crater, while carbon dioxide bubbled to the surface of the milky blue crater lake. Veils of steam wreathed the landscape of loose rock in eerie half-light.

Toxic sulfurous gas, carrying the telltale reek of rotten eggs, wafted through vents in the steep walls of Iceland’s Viti crater, while carbon dioxide bubbled to the surface of the milky blue crater lake. Veils of steam wreathed the landscape of loose rock in eerie half-light.