Earth faces a one-in-six chance of experiencing a massive volcanic eruption this century, scientists warn, and ‘humanity has no plan to address it.’
Such an event, according to climate professor Dr. Markus Stoffel, could trigger ‘climate chaos’ similar to the 1815 eruption of Indonesia‘s Mount Tambora.
That eruption released 24 cubic miles of gases, dust, and rock into the atmosphere, causing global temperatures to plummet.
Crops failed, famine spread, diseases surged, and tens of thousands of people died.
Unlike the ‘Year Without a Summer’ that followed Tambora’s eruption, a 21st-century mega-volcano would add to the disruptions already caused by humanity’s reliance on fossil fuels.
‘The effects could be even worse than in 1815,’ geological scientist Dr. Michael Rampino explained. ‘The world is more unstable now.’
Ironically, the greenhouse gases released over the past century could make the aftermath of such an eruption even colder.
Volcanologist Dr. Thomas Aubry’s research suggests that a hotter, more turbulent atmosphere would spread sulfur dioxide gas—and the cooling sulfate aerosols it forms—more quickly, intensifying the cooling effect.
A wider distribution of these sunlight-reflecting airborne compounds would make them more effective by reducing their chances of colliding and clumping up.
‘There is a sweet spot in terms of the size of these tiny and shiny particles,’ said Cambridge atmospheric scientist Dr Anja Schmidt — a ‘just right’ size range ‘where they are very efficient at scattering back the sunlight.’
Our future and likely hotter atmosphere, according to a study she co-authored with Dr Aubry for Nature Communications in 2021, would remove 30 percent more solar energy in certain ‘global warming’ scenarios coming soon.
‘We suggest that would amplify the surface cooling by 15 percent,’ Dr Aubry said.
But there are also troubling uncertainties, as Dr Stoffel, who teaches at the University of Geneva, told CNN.
‘We’re just at the beginning of getting an idea of what could happen,’ he said.
When it comes to older volcanoes, ‘we have very poor data,’ Stoffel explained, making it more challenging to reconstruct a model of their impact.
To compensate, climate scientists, geologists and other researchers pull together atmospheric data frozen in time within ice cores and embedded in old tree rings.
These measurements suggest that several volcanic eruptions in the past several thousand years temporarily cooled the planet by about 1 to 1.5 degrees Celsius
The epic 1815 Tambora eruption, for example, dropped the average global temperature by about 1 degree Celsius.
And geological evidence suggests that another large volcanic eruption in Indonesia in 1257, the huge Samalas event, likely helped to trigger a ‘Little Ice Age,’ hundreds of years long.
The 1991 explosion of Mount Pinatubo in the Philippines, by contrast, is known more precisely to have cooled Earth for a few years by around 0.5 degrees Celsius, based on modern satellite data that can record how much sulfur dioxide was released.
Even with these added sensors and other seismic instruments, of course, scientists still cannot know a volcano’s future.
‘Which one next and when,’ Stoffel said, ‘that’s still impossible to predict.’
His hope is that research into the possible worst case scenarios might help the public and policy makers better prepare, everything from evacuation plans to preparing food aid in the event of worldwide crop failures.
A 21st century eruption would impact a much more populated and interconnected world where dramatic disruptions could reverberate in deadly and unexpected ways.
Climate change can even alter the behavior of the volcanoes themselves, according to Dr Aubry, who noted that melting and disappearing glaciers above a subterranean pool of magma can lift the pressure that’s keeping it tamped down.
More extreme rainfall, escalated by climate change, can also lead to ‘steam bomb’-like detonations as that moisture seeps deep into the crevices near active and dormant volcanoes alike, he noted.
‘We are currently working to map the volcanoes most sensitive to climate change,’ Dr Aubry told Polytechnique Insights this past October.
‘Roughly speaking, we know that this concerns regions where glaciers are melting fast, such as Iceland or Chile, as well as volcanoes that are heavily affected by precipitation, such as in Indonesia,’ he said.
One 2022 study found that about 716 volcanoes worldwide, or 58 percent of those known to be active and above-ground, could be triggered by more extreme rainfall, Dr Aubry explained, raising the chances of dangerous mini-Ice Age.
‘We can therefore expect potentially more eruptions,’ he said.
