Why did a volcanic eruption cause a 'year without summer' in 1816?

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(CNN) - It happened more than two centuries ago, but its impact remains enormous. Historians have attributed to the infamous "year without summer" of 1816, at least indirectly, the invention of the bicycle and the writing of the classic novel Frankenstein .

In April 1815, Mount Tambora exploded in a powerful eruption that killed tens of thousands of people on the Indonesian island of Sumbawa. The following year became known as the “year without summer” when unusually cold and wet conditions spread across Europe and North America.

Since 1913, researchers have suggested that the two events were linked. Now, a new study shows that the cold summer temperatures of 1816 would not have been possible without the volcanic eruption. The research was published Tuesday in the journal Environmental Research Letters .

The immediate effects of the volcano resulted in massive destruction. The eruption, consequent flows and related tsunamis destroyed homes and claimed 10,000 lives. Another 80,000 would die from a disease that spread later.

"The eruption of Mount Tambora in April 1815 was one of the most explosive of the last millennium," said Andrew Schurer, lead author of the study and associate researcher at the Faculty of Geosciences at the University of Edinburgh. "It had a huge local impact, devastating the island of Sumbawa."

The tremendous amount of material expelled by the volcano contributed to the global impact that followed.

"The eruption injected a large amount of sulfur dioxide into the stratosphere, which would have spread rapidly throughout the world, oxidizing to form sulfate aerosols," said Schurer. “These volcanic aerosols reduce net shortwave radiation, causing extensive and lasting surface cooling. They also lead to a reduction in global rainfall, while humidifying some dry regions and causing dynamic changes in large-scale circulation of both the ocean and the atmosphere. ”

The global temperature fell between one and three degrees Celsius. It was the coldest year in at least the last 250 years, according to the study. Each season showed temperature anomalies, but the summer was the most drastic change: it was the coldest average summer temperature recorded in Europe between 1766 and 2000.

In the summer of 1816, the cold and humid conditions in central and western Europe and even in North America caused the loss of crops, the death of cattle and famine. In New England there was snowfall and "deadly frost." The cloud layer kept the skies gloomy. It was called the "last great subsistence crisis in the western world."

Previous research even suggested that intense clouds and rains from the eruption contributed to Napoleon's defeat at Waterloo three months later in Belgium.

Schurer and his colleagues used previous data and climate models to determine the effect of the volcanic eruption. They compared the data with other years with similar patterns of pressure at sea level.

In similar years, precipitation was comparable, but not low temperatures. When the volcano was introduced on stage, something called volcanic forcing, scientists were able to replicate the summer of 1816.

"The inclusion of volcanic forcing in climatic models can explain the cooling, and we estimate that it increases the probability of extremely cold temperatures up to 100 times," Schurer said. “There is strong evidence in the simulations of the model that the volcanic eruption increases the possibility of such a humid summer in Central Europe by approximately 1.5 to three times. And without the volcanic forcing, it is less likely that it has been so wet and highly unlikely that it has been so cold. ”

The agricultural failure was rampant during this time, and the price of food rose. This also increased the price of oats for horses, which were the main source of transportation at that time, according to the National Center for Atmospheric Research. This has been credited with helping to inspire the invention of the bicycle by Karl Drais in 1817.
Summer, or lack thereof, in 1816 also inspired something else: Gothic tales.

Lord Byron, Claire Clairmont, Dr. John William Polidori, Percy Shelley and Mary Godwin (before marrying Shelley) stayed in a villa overlooking Lake Geneva in Switzerland. But the weather in its idyllic surroundings was bleak.

During one of his discussions, Byron suggested that each member of the restless group write a ghost story to share. Within a few weeks, Godwin had written Frankenstein , Byron wrote his poem Darkness and Polidori wrote his story The Vampire .

Volcano