In April of 1815, Mount Tambora exploded in a powerful eruption that killed the tens of thousands of people on the Indonesian island of Sumbawa. The following year became known as the "year without a summer" when unusually cold, wet conditions swept across Europe and North America.
The immediate effects of volcano caused in mass destruction. The eruption, the flows that came from it and the related tsunamis destroyed homes and claimed 10,000 lives. Another 80,000 would die from a disease that spread in the aftermath.
"The Mount Tambora eruption in April 1
The tremendous amount of material ejected by the volcano contributed to the global impact that followed.
"The eruption injected a huge amount of sulfur dioxide into the stratosphere, which would have a rapid spread across the world, oxidizing to the form of sulfate aerosols," Schurer said. "These volcanic aerosols reduce net shortwave radiation causing widespread, long lasting surface cooling. They also lead to a reduction in global rainfall, while wetting some dry regions and causing dynamic changes in the large-scale circulation of both the ocean and atmosphere."  The global temperature drops between one and three degrees Celsius. It was the coldest year in the last 250 years, according to the study. Each season showed temperature anomalies, but the summer was the most drastic change, with the coldest recorded mean summer temperatures for Europe between 1766 and 2000.
Schurer and his colleagues used early data and climate models to determine the effect of volcanic eruption. They compared the data against other years with similar sea-level pressure patterns.
In similar years, the precipitation was comparable, but not the cold temperatures. When the volcano was introduced to the scenario, a step called volcanic forcing, the scientists were able to replicate the summer of 1816.
"Including volcanic forcing in climate models can account for cooling, and we estimate it increases the likelihood of extremely cold temperatures by up to 100 times," Schurer said. "There is strong evidence in model simulations that volcanic eruption increases the chance of such a wet summer over Central Europe by about 1.5 to three times. And without volcanic forcing, it is less likely to have been wet and highly unlikely to have been as cold. "
The summer, or lack thereof, in 1816 also inspired something else: Gothic tales.
During one of their 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 penned his poem "Darkness" and Polidori wrote his short story, "The Vampyre."