The forgotten volcano: how an 1831 eruption changed the world

In 1831, the Zavaritskii volcano triggered a devastating eruption, darkening the skies and cooling the planet: after two centuries, science reconstructs its history

In 1831, one of the most spectacular moments took place on Earth: an unknown volcano erupted in such a way that it darkened the skies and lowered temperatures by about 2°F across the whole Northern Hemisphere. The aftereffects were catastrophic: crop failures, famines in Europe, India, and Japan, leaving millions of people to cope with hunger and desperation. For nearly two hundred years, no one knew who was responsible. Thanks to scientific investigation, we can now identify the guilty volcano as Zavaritskii on the remote island of Simushir in the Kuril Islands, between Russia and Japan.

Unmasking the hidden criminal

Due to its location and a total absence of residents on Simushir Island, the Zavaritskii volcano has never been properly monitored. For quite some time, the eruption in 1831 was thought to come from a tropical volcano until it was identified through the analysis of an ice core extracted from Greenland, where minute volcanic ash particles had been trapped for many centuries.

One of the lead researchers, Dr. William Hutchison, called it a heart-skipping-a-beat moment when, for the first time, the volcanic ash samples matched perfectly with rocks from Simushir Island:

“It was a spine-tingling moment, a true eureka. The data was incredibly clear.”

One of the most powerful eruptions in the 19th century came from a volcano named Zavaritskii. The tremendous amount of sulfur dioxide sent into the atmosphere cooled global climates, further contributing to the already harsh conditions of the Little Ice Age.

The global consequences of an “invisible” volcano

The effects were immediate and devastating: the suddenly cold, dry climate drastically reduced crop yield, and famines that did indeed affected millions. As Hutchison explains:

“The social fallout was immense, and understanding just how much climate played a role in these tragedies is one of the goals of current research.”

But how could such a big event go by unnoticed for such a long period of time? This is where extreme geographic isolation comes in. The island was so far from the rest of the world that even travelers of the time could hardly record its eruption effects with higher veracity. The only recorded evidence, apart from the ice samples, is recorded in the logbook of passing-by sailors.

Zavaritskii: a warning for the future

The story of Zavaritskii is instructive. Not all the most dangerous volcanoes are famous and well-monitored. Many, like Zavaritskii, are located in remote and inaccessible areas. This makes it hard to predict and mitigate the effects of future eruptions, as Hutchison warns:

“We don’t have a really effective international system to handle large-scale eruptions. It’s something we need to work on as a scientific community and as a society.”

Volcanic eruptions can change the course of history, as was seen in 1831. With climate change already underway, similar events could have even more dramatic consequences in an increasingly vulnerable world.

Source: PNAS