May 7, 2021

I, Science

The science magazine of Imperial College

If an asteroid decided to take a shine to our watery planet, couldn’t we distract it with a gentle nudge, or a handsome movie star with an enormous bomb? And if we get overrun by superbugs, or consumed by the Sun, or if Cheryl Cole stops making sweet music, surely we could do something, before things got really out of hand? Yes, in the face of most global catastrophes, we’d be alright.  However, there is one force of nature that noone can hide from.

Last year our television screens and Facebook feeds were filled with terrible scenes of the unpronounceable Icelandic volcano Eyjafjallajökull, spewing ash over Europe and causing chaos across the western world. However, variations on “I got stuck in the Dominican Republic, and we had to stay at our hotel for an extra week!” was about as bad as it got.

The truth is, none of us have really seen what a volcano is capable of. What we witness are tiny, insignificant dribblings of lava and little puffs of ash; mere schoolboy demonstrations of the power that volcanoes possess.

About 74,000 years ago, in what is now the Lake Toba region of Sumatra, the largest explosive event of at least the past 100,000 years occurred. Toba’s supervolcano erupted with unfathomable power, releasing the force equivalent to 100 million Hiroshima bombs. Palaeoclimatologists believe that it triggered a period of global cooling which may have caused a ‘bottle neck’ in human evolution – a near extinction of the entire human race.

“Perhaps most worrying for us would be the huge volume of sulphuric compounds released into the atmosphere, which could cause a global ‘volcanic winter’ by reflecting incoming solar radiation.”

Toba was by no means an isolated event. Proponents of the ‘Armageddon asteroid’ might like to take note of a 2005 British report, which found that a supervolcano eruption is five to ten times more likely than a globally destructive asteroid impact.

So should we be building underground bunkers and organising a mass exodus to the moon? The chance of a supervolcano eruption happening tomorrow is pretty small, but in short, no one really knows when the next supereruption will be. Many volcanologists believe that when it does happen, it will shatter the peaceful, unassuming beauty of Wyoming, USA.

Yellowstone National Park is a veritable talent show of volcanic activity, containing geysers, steam Ivents, mud volcanoes and steaming hot springs.  To top it all off, the national park sits on an underground magma chamber with a volume 6,000 times that of an Olympic swimming pool. If any volcano has the potential for a supereruption, Yellowstone would be it.

A huge area of the United States would be devastated if Yellowstone unleashed its awesome power. Perhaps most worrying for us would be the huge volume of sulphuric compounds released into the atmosphere, which could cause a global ‘volcanic winter’ by reflecting incoming solar radiation. The knockon effects of widespread famine, disease pandemics, and the collapse of agriculture and infrastucture would cause social and political upheaval. It is extremely difficult to predict the overall impact of a supervolcanic eruption, since changes in climate would vary depending on the eruption’s latitude. It would be fair to say that the effects would be, in all cases, devastating.

Supervolcano eruptions are unpredictable, unstoppable and above all, inevitable. However, as the official line from the US Geological Survey (USGS) states, “there is no evidence that a catastrophic eruption at Yellowstone is imminent.”  The USGS also freely admits that the ground surface of the volcano is indeed ‘inflating’, albeit very slowly. And there are always the other supervolcano candidates to consider; Long Valley, California; Lake Taupo, New Zealand; the Valles Caldera, New Mexico; Aira, Japan, to name a few.

In short, we should hope that our volatile planet continues to behave itself. If a supervolcano is unleashed, there will be a lot more to worry about than a few cancelled flights and an extended holiday in the Caribbean.