Nearly 200 years ago, a mysterious volcano cooled the Earth, bringing famine and death. It has finally been discovered.

In 1831, somewhere on the surface of the Earth, a massive volcano awakened and erupted so much ash and smoke that the sky darkened, cooling the Northern Hemisphere. This resulted in crop failures and widespread hunger among the population. Yet, despite all the devastation, scientists were unable to pinpoint the location of the volcano for centuries, as reported by Science Alert.

Now, thanks to a meticulous analysis of ash from the eruption that was captured and preserved in the Greenland ice sheet, a team of researchers led by volcanologist William Hutchinson from the University of St Andrews in the UK has finally identified the culprit.

In a new study, scientists have finally linked this massive event to the Zavaritsky volcano, located on Simushir Island in the Kuril Islands — an untouched stretch of land just 59 kilometers long, situated between Russia and Japan.

During the study, Hutchinson and his colleagues compared the composition of microscopic ash fragments extracted from Greenland's ice cores with samples from the Zavaritsky caldera. The results showed a perfect match. According to Hutchinson, the search for matches took considerable time and required extensive collaboration with researchers from Japan and Russia, who provided samples collected from various volcanoes over the decades.

In the laboratory, the scientists analyzed two ash samples, one from the volcano and the other from the ice core, and they turned out to be identical. The researchers then proceeded to analyze the age and size of the eruption in the records of the Kuril Islands.

Today, researchers around the world have access to a toolkit that allows them to identify sites of geological activity. However, nearly 200 years ago, scientists could not utilize global seismic monitoring stations and low-Earth orbit satellites. Consequently, an eruption from a remote island, no matter how significant, easily slipped past researchers' notice.

One eruption that was believed to have caused global cooling from 1831 to 1833 was attributed to Babuyan Claro in the Philippines. However, as early as 2018, scientists discovered that this event never actually occurred. Another theory, based on sulfur, suggested that the volcano might be located on Graham Island — a disappearing and reappearing volcanic massif in the Strait of Sicily.

In the course of the new study, the researchers also discovered a crater that supports their conclusions. Today, the Zavaritsky volcano lies beneath a caldera — a hollow basin that remains after a volcanic explosion. This caldera likely formed during the 1831 eruption.

The researchers believe that the volumes of ash and smoke ejected by the volcanic eruption would have been sufficient to cause a cooling of about 1 degree Celsius. For comparison, this is similar to the eruption of Mount Pinatubo in the Philippines in 1991.