According to Nasa, no known asteroids will threaten Earth for at least a century. We’ve got our collective eye on more than 98 per cent of near-Earth asteroids. That’s great for avoiding a real-world Armageddon panic, but there’s potentially a much bigger threat a lot closer to home. It could be hiding right beneath your feet...
There are about a dozen supervolcanoes on Earth. If one of them explodes, it will propel masses of sulphur into the atmosphere, cloaking vast swathes of our planet in dust and cutting off sunlight. Without sunlight, the Earth will cool. Crops will struggle to grow. People will starve and die.
Nobody living on this planet has experienced a supervolcano eruption. The last was 74,000 years ago, at Mount Toba on the Indonesian island of Sumatra. Researchers believe that the explosion spewed ash across a radius of 4,350 miles. An eruption of that size could throw aerosols (fog, dust and geyser steam) into the atmosphere, launching us into a volcanic winter. This would lower the global temperature by a few degrees and radically change the climate.
In the northwest of America, magma bubbles beneath the Earth’s crust in one of the world's biggest and most dangerous supervolcanoes. Scientists believe that a plume of magma rises from the very centre of the Earth to power the volcanism of Yellowstone National Park’s supervolcano. Known as a hotspot, this molten lava has caused three explosive eruptions over the past 2.1 million years. These eruptions created large cauldron-like depressions known as calderas. The largest caldera on Earth is now referred to as the Yellowstone supervolcano.
“The Yellowstone Volcano has the potential to really wreck havoc,” says Rosaly Lopes, a volcanologist and manager of the planetary science section of Nasa’s Jet Propulsion Laboratory. Before you let panic settle in, know that scientists believe a super eruption at Yellowstone is highly unlikely. It’s going not to erupt tomorrow, and the chance of even witnessing one in our lifetime is infinitely minute. But should we still have a plan to mitigate a potential eruption? Could we?
The short answer is: we don’t know. We don’t know whether we have – or will ever have – the capability or technology to stop such an event and whether there would be any point in trying. Any attempts could exasperate the problem and potentially even trigger an eruption itself.
“We as humans don’t have the capacity at this moment to stop a big volcano from erupting,” says Yellowstone Park geologist Jefferson Hungerford. “How would we stop an eruption? The underlying premise there is to take the energy out of the system – that energy being heat – and we can’t do that right now.” Spanning 3,472 square miles and three states (Wyoming, Montana and Idaho), there is lots of heat energy in Yellowstone caldera.
Asteroid impacts which are less than two kilometres wide occur half as often as supervolcano eruptions, but they would both wreck similar devastation on our planet. Brian Wilcox, a senior engineer at Nasa, was part of a group dedicated to defending the Earth from asteroids. He realised it was time we were as prepared for a supervolcanic eruption as we are for asteroid impacts. He got a team together at the Jet Propulsion Laboratory at Nasa, including Lopes, and they began tentatively working out some back-of-an-envelope calculations. They wanted to start asking a radical question: could we drill into this volcano to mitigate a super eruption?
“This was just to start thinking if it’s feasible to use the technology we have now to cool a magma chamber and therefore prevent an eruption,” says Lopes. Yellowstone was used as an example for their study, but the work applies to any supervolcano. These eruptions are defined as being greater then or equal to a magnitude eight on the Volcanic Explosivity Index.
The idea was to drill a ring around the magma chamber then begin circulating water, gradually moving closer to the centre. This would hypothetically release pressure from the magma plume and cool it down. This in itself would take around 50,000 years, says Lopes.
Michael Poland, scientist-in-charge of the Yellowstone Volcano Observatory and Hungerford rebuke Nasa’s study, and Lopes is keen to emphasise that it was never a plan. It was more an exploratory study, like dipping your toes into the vastness of the Atlantic Ocean to see how it ripples.
“It was a simple report that got sensationalised,” says Hungerford. “It’s fun to think about, however the science isn’t there and the idea is fraught with other problems.” Poland and Hungerford also agree that if Yellowstone were to erupt, it would be as a lava flow rather than an explosion, just like it did 70,000 years ago. The best tool we have right now is simply to monitor Yellowstone’s activity closely. Hungerford is part of this process and says there is no sign of impending eruption. “We observe Yellowstone volcano by looking at the swelling in the volcano, seismicity, gas emissions and changes in heat from the system. None of the signals come close to suggesting any volcanic activity is in our future,” he says.
“Various studies have found out that a lot of the magma chamber at Yellowstone is pretty solid,” says Lopes. So why bother trying such an expensive and risky plan if there’s not really a threat to mitigate? Because, Lopes believes, Yellowstone has the potential to power a cheaper and cleaner energy future.
Read more: Supervolcanoes could be the key to our battery-powered future
“It’s feasible that we could use Yellowstone’s magma chamber as a source of geothermal energy,” she says. This has already been successfully done in Iceland, where geothermal power facilities currently generate 25 per cent of the country’s total electricity production. There is also the question of whether Yellowstone is really where we should be focusing our efforts. Whilst researchers aren’t expecting a super eruption at the site, other supervolcanoes have erupted on a smaller scale. “Even if it were possible, it would be better to focus on volcanoes that erupt more frequently and threaten larger populations,” Poland says. Bali’s Mount Agung volcano is about to erupt. Experts have warned us that Iceland’s biggest volcano, Bardarbunga, is ready to erupt again. In 2010, when Eyjafjallajökull erupted, it caused travel delays as ash in the atmosphere clogged up plane engines. Millions of people also live around Vesuvius, near the city of Naples in Italy. The volcano, which destroyed Pompeii in 79 A.D., erupts every few decades. “Eruptions from Vesuvius are far smaller than those from Yellowstone,” Poland says. “So if there were an ability to stop a volcano from erupting, that’s the sort of volcano that would demand attention.”
Campi Flegrei and Mount Vesuvius in Italy are studied by Dr Luca Siena, who is also a professor at the department of geology and petroleum geology at Aberdeen University. “The Nasa plan is probably less risky than what has been done in the past at Campi Flegrei, where a well was drilled near to the city, very quickly,” he says. “Because the earth is very hot and high-pressured, the drilling didn’t go well – after 500 metres the well broke.” Despite this, he’s still a fan of Nasa’s idea of continuous, progressive drilling. “We have to do much more than what we are doing now to try and prevent a supervolcanic eruption,” he says.
“These volcanoes are going to do something one day – and this could be in 100 years, in 1,000 years, or even 10,000 years. We expect still to be on the Earth in 10,000 years and if we don’t do something to decrease the stress of this volcano, we won’t be able to survive on the surface of the Earth,” Siena says.
He talks about the public’s reluctance to fund something that won’t affect this generation, and how a super eruption is not on the political agenda right now, when so many other immediate threats exist. “It’s not a problem that we may experience tomorrow, in one year or 100 years but it is surely a problem that, if we don’t tackle it now, it could be too late,” he says.
But if we are to start seriously considering our ability to mitigate a super eruption, we need to improve our imaging techniques, says Siena. “We cannot see inside the Earth in the way we see through a window,” he says. “We should obtain the best possible image of the upper structure of the volcano. Once we know what’s in there, then it can go forward.”
Scientists are in agreement that the best way to predict an eruption is to understand a volcano’s patterns of behaviour. “We are still trying to figure out the variables that go into triggering an eruption at depth,” says Hungerford. If conditions at Yellowstone do begin to change, it’s the job of Michael Poland to initiate the Hazard Response Plan from his observatory in Vancouver, Canada. And that starts with emails.
“If there were alarming changes, it would probably start with a few emails to other Yellowstone Volcano Observatory workers to make sure that the changes were not an instrumental or seasonal artefact of some kind,” he says. “Then we discuss what the activity might mean, whether what is occurring is outside of historical norms, and what the outcome might be.”
If they believe it could be something to worry about, they would let the world know. “If things did accelerate to levels of activity that were really unprecedented and characteristic of what we would expect to see prior to an eruption, we would adjust the alert levels for the volcano.” Changing the alert levels is not done lightly. “Yellowstone alert levels have never been changed from the lowest levels because we’ve never seen anything that was really indicative of a likely eruption.”
But, with a proposed one in 700,000 annual chance of an eruption at the site, Lopes and Siena still think there’s a point in exploring our options.
“If 50 years ago someone said an asteroid is coming towards Earth and there is nothing we could do about it, they would have been right. We wouldn’t have conceived it being possible. But now, there are feasible ways,” says Lopes. “This is a multi-generational task. We don’t know what future generations will be able to do.”
This article was originally published by WIRED UK
