Scientists solve mystery of 1831 volcanic eruption that triggered global cooling

A team of researchers from the University of St Andrews has uncovered the long-standing mystery surrounding a volcanic eruption that caused global famines and crop failures nearly 200 years ago.

The eruption, which occurred in 1831, led to a significant cooling of the Earth's climate, dropping temperatures by approximately 1°C, according to a piece by The Independent.

For decades, scientists were unsure of the exact volcano responsible, but recent research has pinpointed the culprit: the Zavaritskii volcano, located on the remote and uninhabited island of Simushir in the Kuril Islands. This island, currently controlled by Russia, holds strategic importance and was used by the Soviet Union during the Cold War as a secret nuclear submarine base, with submarines docked in a flooded volcanic crater.

The discovery came after the research team, led by Dr. Will Hutchison from the School of Earth and Environmental Sciences, analysed ice core records from the 1831 eruption. By studying ash deposits within the ice cores, the scientists found a perfect match with the chemical signature of ash from the Zavaritskii volcano. The research, published in Proceedings of the National Academy of Sciences on December 30, confirmed that the eruption occurred during the spring or summer of 1831.

Dr. Hutchison explained that advances in technology over recent years have enabled scientists to extract microscopic ash shards from polar ice cores and conduct detailed chemical analyses. "These shards are incredibly minute, roughly one tenth the diameter of a human hair," he said. "We analysed the chemistry of the ice at a very high temporal resolution. This allowed us to pinpoint the precise timing of the eruption to spring-summer 1831, confirm that it was highly explosive, and then extract the tiny shards of ash."

The breakthrough was made possible through collaboration with Japanese and Russian colleagues, who provided ash samples collected from remote volcanoes decades ago. "The moment in the lab when we analysed the two ashes together was a genuine eureka moment," Dr. Hutchison recalled. "I couldn’t believe the numbers were identical. After this, I spent a lot of time delving into the age and size of the eruption in Kuril records to truly convince myself that the match was real."

This new research underscores the volcanic activity in the Kuril Islands, which has long been understudied despite the region's high level of volcanic activity.

By Vugar Khalilov