Scientists finally reveal cause of 1831's global cooling event that caused crop failures and devastating famines

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It's been nearly 200 years since a global cold snap led to widespread crop failures and devastating famines. 

Now, a new study by scientists at the University of St Andrews finally pinpoints the cause. 

The Zavaritskii volcano on the remote, uninhabited Russian island of Simushir, part of the Kuril Islands, erupted in 1831, the experts reveal. 

The dramatic event injected volcanic ash into the atmosphere, blocking enough sunlight to induce a brief global cooling period. 

And the resulting change in weather included reduced rainfall from Africa and India to Japan, causing major famine due to poor crop yields. 

'While scientists have long known that a really big eruption went off in 1831 the source has remained a mystery,' lead study author Dr Will Hutchison told MailOnline. 

'Our chemical fingerprinting of the ash reveals the source of this mysterious climate-changing eruption was this remote volcanic island in the Kurils.' 

Zavaritski has not erupted since 1957, but it is still considered an active volcano – meaning it has the potential to erupt again in the future. 

The mystery location of a giant volcanic eruption that has puzzled scientists for almost 200 years has finally been solved. Pictured, Zavaritskii Caldera, the newly-revealed location of the 1831 eruption 

In the summer of 1831, a massive volcanic eruption spewed sulphurous gases into the atmosphere, reflecting sunlight and causing a global cooling of about 1.8°F (1°C). 

This cold weather, well-documented worldwide at the time, led to 'significant Northern Hemisphere climate cooling' causing crop failure and famine, the team say. 

Historical observations make reference to a blue, purple, and green sun at various Northern Hemisphere locations in August 1831. 

Such phenomena are caused by scattering and adsorption of solar radiation in a dense aerosol plume typically caused by a volcanic eruption. 

Even German composer Felix Mendelssohn wrote about the terrible conditions during his summer journey through the Alps in 1831.

Mendelssohn said: 'Desolate weather, it has rained again all night and all morning, it is as cold as in winter, there is already deep snow on the nearest hills…' 

While scientists knew it was a major event that caused climatic change and societal upheaval, the identity of the volcano responsible remained unknown and fiercely debated – until now. 

For the study, Dr Hutchison and his team analysed records of ice cores from the polar ice sheets of Greenland, dating back to 1831. 

Dr Hutchison and his team were able to date and match the ice core deposits to Zavaritskii volcano on the remote, uninhabited island of Simushir (pictured), part of the Kuril Islands

Dr Hutchison and his team were able to accurately date and match the ice core deposits to Zavaritskii volcano on the remote, uninhabited island of Simushir, part of the Kuril Islands

These cylinders of ice are a valuable record of climate conditions at the time of formation, including local temperature, the chemical composition of the atmosphere and, crucially, volcanic activity.

'Scientists drill into the ice and pull up layers of snow and ice which give us yearly records of past climate and at atmospheric conditions,' Dr Hutchison said. 

'Only in recent years have we developed the ability to extract microscopic ash shards from polar ice cores and conduct detailed chemical analyses on them. 

'These shards are incredibly minute, roughly one-tenth the diameter of a human hair.' 

Following lab analysis, they identified a 'perfect fingerprint match' with ash deposits from the remote Kuril Islands. 

'We were able to identify Zavaritski as the source because the magma it produces has a distinctive chemistry, different from the neighbouring volcanoes,' Dr Hutchison told MailOnline.

The study, published in the journal Proceedings of the National Academy of Sciences, finally solves a nearly 200-year mystery. 

The 1831 eruption was initially attributed to Babuyan Claro volcano in the Philippines, but a previous study 'found no firm evidence for an eruption at this time'. 

For the study, ice cores (pictured) were collected from various locations across the Greenland ice sheet. These cylinders of ice are a valuable record of climate conditions at the time of formation, including local temperature, the chemical composition of the atmosphere and, crucially, volcanic activity

The 1831 eruption was initially attributed to Babuyan Claro volcano in the Philippines (pictured), but a previous study 'found no firm evidence for an eruption at this time'

Another candidate has been Ferdinandea (also known as Campi Flegrei Mar Sicilia or Graham Island) which is located about 30 miles (50km) southwest of Sicily, Italy. 

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Ferdinandea did erupt in July to August 1831, however, this was only a 'modest' 'phreatomagmatic' eruption, resulting from magma erupting through water. 

'The magnitude of the Ferdinandea eruption is also unusually small for a climate-changing eruption,' the team say in their paper. 

The study also adds to the history of the Zavaritski volcano, which helps to establish a record of when it has erupted in the past. 

The 1831 eruption was very remote, yet it had a significant global impact on climate and severe consequences for human populations. 

However, predicting volcanic eruptions is difficult, even with historical eruption data.   

'This island is uninhabited, no one monitors this volcano, so our work illustrates just how hard it will be for scientists to detect when and where the next big climate eruption will take place,' added Dr Hutchison.