Scientists and archaeologists have discovered ancient tales of a particularly cold summer from the year of 1258. It has been called the "year without a summer" and was describing these ancient texts as being unseasonably cold resulting in poor harvests that were also devastated by heavy flooding. Those ancient reports indicate that thousands of people were buried in mass graves around London that year.
Scientists believe these mass graves were the result of the poor weather and the lack of food. Exactly what caused the unseasonably cold summer was something of a mystery, but scientists believe they have figured it out. The researchers believe that the cold summer was caused by a massive volcanic eruption that would have thrown as much is 10 cubic miles of rock and dust into the atmosphere.
The scientists estimate that the plume of dust and ash would have been as high as 25 miles above the ground. That sort of plume wouldn't have had global effects according to the scientists blocking out sunlight and creating a dramatic cooling effect on earth. This is what the team believes led to the year without summer.
The sort of event isn't without precedent, Mount Pinatubo in the Philippines erupted in 1991 throwing up approximately 2.4 cubic miles of rock. That blast decreased the amount of sunlight reaching the Earth by 10% and created a temporary drop of 0.7-degrees Fahrenheit in global average temperatures. The eruption in 1258 through more than three times that amount of rock and dust.
The researchers believe they have now identified the source of the volcanic eruption that caused of the devastation in 1258. The scientists believe the volcano that caused the massive medieval explosion is the Samalas volcano in the Mount Rinjani complex on the Indonesian island of Lombok. Scientists are continuing to study the volcano and the explosion for more clues.