STORY: This is Iceland’s Askja volcano, one of the country’s most active and dangerous.
:: Vatnajokull National Park, Iceland
It’s been in a state of unrest since 2021. Scientists don’t know exactly when it could erupt.
But they now worry the effect of climate change on Iceland’s glaciers could hasten and intensify that next volcanic event.
:: Michelle Parks, Volcanologist
“I think it’s very likely that we will see future changes. But the question, of course, is when will this start happening and by how much will it affect volcanic activity?”
Michelle Parks, a volcanologist with the Icelandic Meteorological Office, has been keeping tabs on Askja for years.
Including – the Viti crater.
Its name is derived from the Icelandic for “hell” – and it was formed during a massive eruption in 1875.
Parks and her colleagues closely monitor the temperature and acidity of Viti’s crater lake for any changes.
“So at the moment, I’m measuring the pH of the water in this small crater lake here. And this is important so that we can determine the acidity of the lake and how it’s changing over time. Because this could be indicative of changes in magmatic activity.”
A jump in either, meaning that more gases are pushing in from below, would suggest the volcano is moving closer to an eruption.
One which, scientists worry, could be catastrophic.
On the scale volcanologists use to measure the size of explosive eruptions, Askja could match that of the 1980 eruption of Mount St. Helens in Washington state.
Although it is much more likely to be a smaller eruption, scientists can’t rule out the alternative.
But Parks and her team are back at Askja this year with a higher purpose.
They are testing a theory in Iceland that could have dire implications for millions of people: Whether rapid glacial melt, caused by climate change, could trigger more eruptions among the hundreds of volcanoes sitting under ice worldwide.
“Iceland is essentially one of the best places in the world to study this. It’s a natural laboratory because we have both volcanism and glaciers.”
Ice still weighs on more than half the nation’s 34 active volcanic systems, but it is rapidly melting as global temperatures climb.
Scientists predict roughly half of the remaining volume of glaciers will be gone by this century’s end.
“So at the moment, glaciers cover approximately 10% of Iceland. And the glaciers are presently retreating as a result of current day global warming. So this can influence on volcanism in a number of ways.”
The main way is through weight.
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 volcanoes to produce more magma and can alter its movement, influencing eruptions.
Askja itself is no longer covered by glaciers, but could be affected by the retreat of the nearby Vatnajokull ice cap.
:: Freysteinn Sigmundsson, Geophysicist
“We know of Iceland as a land of fire and ice, a continuous fight against fire and ice, the eruptions and the ice caps. So we know it has been a difficult time.”
Geophysicist Freysteinn Sigmundsson says he has visited Askja volcano almost every year since 1990.
He says predicting eruptions is an imprecise science. There might not always be weeks of seismic activity as a warning of a looming eruption.
So far, Askja’s metrics have remained stable, but the scientists aren’t taking that for granted.
Parks says the aim of their studies in Iceland is ultimately the bigger picture: the future of volcanic eruptions in the country, and what impacts they might yield for the world beyond.