‘Mystery Volcano’ Identified: 1831 Eruption Cooled Earth, Scientists Discover
Scientists have finally identified the “mystery volcano” responsible for a massive 1831 eruption that significantly cooled the Earth’s climate, CNN reports.
For nearly two centuries, the location of this powerful eruption, one of the most impactful of the 19th century, remained unknown.Now, research published Monday in the journal Proceedings of the National Academy of Sciences points to Zavaritskii volcano on Simushir Island, part of the Kuril Islands archipelago in the northwest Pacific Ocean, as the culprit.
The 1831 eruption spewed vast amounts of sulfur dioxide into the stratosphere, causing a drop of roughly 1 degree Celsius (1.8 degrees Fahrenheit) in annual average temperatures across the Northern Hemisphere. This occurred during the tail end of the Little Ice Age, one of the coldest periods on Earth in the past 10,000 years, exacerbating existing harsh conditions.
Researchers solved the mystery by analyzing ice cores from Greenland, which contained layers of sulfur isotopes, ash grains, and microscopic volcanic glass shards deposited between 1831 and 1834. Using geochemistry, radioactive dating, and computer modeling to trace the particles’ origins, the team connected the eruption to Zavaritskii, a volcano previously thought to have been dormant since 800 BC.
Prior to this discovery, scientists had considered other volcanoes, including those closer to the equator. D
Analysis of the Greenland ice cores revealed that sulfur fallout in 1831 was 6.5 times greater in Greenland than in Antarctica, strongly suggesting a Northern Hemisphere origin. Microscopic volcanic ash and glass shards from the ice cores matched samples taken from the Zavaritskii caldera. Radiocarbon dating of volcanic ash on Simushir Island confirmed the eruption occurred within the last 300 years.
The study also determined that the volcano’s caldera formed after a massive eruption between 1700 and 1900, making Zavaritskii the prime candidate for the 1831 event.
The 1831 eruption at Zavaritskii, along with eruptions from Mount Tambora in 1815 and Coseguina in 1835, contributed to the end of the Little Ice Age. These volcanoes caused a notable drop in average temperatures in the Northern Hemisphere. After the 1831 eruption, cooler and drier conditions caused widespread crop failures and famines across India, Japan, and Europe, affecting millions.
The discovery highlights the potential for remote volcanoes, like those in the Kuril Islands, to have significant global impacts on climate and human populations. With many volcanoes worldwide poorly monitored, scientists warn of the need for better systems to predict and respond to future large-magnitude eruptions.
