February 19, 2013 – The Iceland Volcanic Eruptions, from 1783 to 1784, Killed Six Million People World-Wide: During that time period, a series of large volcanic eruptions occurred along the Laki Fissure Zone, roughly from Mount Katla and extending northeast to Mount Grimsvotn (see map). The Mount Grimsvotn volcano has the highest eruption frequency of all the volcanoes in Iceland. The massive climate-impacting Laki fissure eruption had a shattering impact on the climate of the world and killed over six million people. The eruptions reached heights of between 2,500 to 4,500 feet, and occurred over an eight month period during 1783-1784 from the Laki fissure and the adjoining Grimsvotn volcano. This event ejected an estimated 3.4 cubic miles of basalt lava and clouds of poisonous hydrofluoric acid and sulfur-dioxide compounds that killed over 50% of Iceland’s livestock population, leading to a famine which killed approximately 25% of the population of the country.
The Laki eruption, and its aftermath, has been estimated to have killed over six million people globally, making it the deadliest volcanic eruption in historical times. The drop in temperatures, due to the poisonous gases discharged into the northern hemisphere, caused crop failures in Europe, droughts in India, and Japan’s worst famine.
On June 8, 1783; a fissure with 130 craters opened with phreatomagmatic explosions, which are eruptions generated as a result of the interaction between water and magma. This event is rated as VEI 6 on the Volcanic Explosivity Index, which goes from 1 to 8. The eight month emission of poisonous gases resulted in one of the most important climatic and socially repercussive events of the last thousand years.
The outpouring of gases, including an estimated 8 million tons of hydrogen fluoride and estimated 120 million tons of sulfur dioxide, gave rise to what has since become known as the “Laki haze” across Europe. In Great Britain, the summer of 1783 was known as the “sand-summer” due to ash fallout. The gases were carried by the convective eruption column to altitudes of 10 miles (52,800 feet).
Benjamin Franklin recorded his observations in a 1784 lecture as follows: “During several of the summer months of the year 1783, when the effect of the sun’s rays to heat the earth in these northern regions should have been greater, there existed a constant fog over all Europe, and a great part of North America. This fog was of a permanent nature; it was dry, and the rays of the sun seemed to have little effect towards dissipating it, as they easily do a moist fog, arising from water. They [the Sun’s rays] were indeed rendered so faint in passing through it, that when collected in the focus of a burning glass they would scarce kindle brown paper. Of course, their summer effect in heating the Earth was exceedingly diminished. Hence the surface was early frozen. Hence the first snows remained on it unmelted, and received continual additions. Hence the air was more chilled, and the winds more severely cold. Hence perhaps the winter of 1783-4 was more severe than any that had happened for many years.”
An estimated 120 million tons of sulfur dioxide was emitted during the Laki Fissure Eruption, which is three times the total annual European industrial output in 2006, and equivalent to a 1991 Mount Pinatubo eruption occurring every three days. Eight months of Laki Fissure Euruptions, or 240 days, equals the equivalent of 80 Mount Pinatubo eruptions. This outpouring of sulfur dioxide caused a thick haze to spread across Western Europe, throughout 1783 and the winter of 1784.
In North America, the winter of 1784 was the longest and one of the coldest on record. It was the longest period of below-zero temperatures in New England, the largest accumulation of snow in New Jersey, and the longest freezing over of the Chesapeake Bay. There was ice skating in Charleston Harbor, a huge snowstorm hit the south, the Mississippi River froze at New Orleans, and there was ice in the Gulf of Mexico.
The Master of Disaster