Volcano That Cooled Earth by 1°C Identified Nearly Two Centuries Later

A volcanic eruption that occurred in 1831 and significantly impacted the global climate has finally been attributed to a volcano in the northwest Pacific Ocean. The discovery, published in the journal Proceedings of the National Academy of Sciences, sheds light on a phenomenon that marked the end of the so-called “Little Ice Age.”

The Eruption’s Impact
The 1831 volcanic explosion was one of the most powerful of the 19th century, ejecting massive amounts of sulfur dioxide into the atmosphere. This led to an average temperature drop of 1°C across the Northern Hemisphere, disrupting the global climate for years.

While the year of the eruption was known, the volcano’s location remained a mystery for nearly 200 years. Researchers finally pinpointed it by analyzing ice core samples from Greenland, which revealed sulfur isotopes, volcanic ash, and glass fragments deposited between 1831 and 1834.

Identification Methods
To solve the mystery, scientists used advanced techniques, including geochemistry, radiometric dating, and computational modeling. These tools allowed them to trace the particles from the eruption back to the Zavaritskii volcano, located on Simushir Island, part of the Kuril Islands archipelago, a territory disputed between Russia and Japan.

Zavaritskii is an extremely remote volcano, with scarce historical records limited to occasional accounts from ships passing through the area. Before this discovery, the volcano’s last documented eruption dated back to 800 B.C.

Initial Assumptions and the Eureka Moment
Initially, scientists believed the 1831 eruption had occurred closer to the Equator, in regions such as the Philippines. However, laboratory analyses comparing volcanic ash from Zavaritskii with those found in the ice cores provided a surprising match.

“The moment we analyzed the ashes side by side was a true ‘eureka moment.’ It’s astonishing that an eruption of this magnitude wasn’t more thoroughly documented,” said Dr. William Hutchison, the study’s lead author, in an interview with CNN.

The End of the Little Ice Age
The Zavaritskii eruption was one of four major volcanic events between 1808 and 1835. These eruptions contributed to the decline of the Little Ice Age, a period of anomalous climate conditions that began around 1400 and ended by 1850.

This discovery underscores the importance of volcanic research in understanding the impact of natural phenomena on Earth’s climate and history.

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