Starting on 8 June 1783 and continuing on until until 7 February 1784, hell on earth came to Iceland. The Lakagígar (Craters of Laki), a a 25 km (15.5 mi) long volcanic fissure with 130 craters opened up on the side of Laki mountain, and over 8 months it spewed 14 km3 (3.4 cu mi) of basalt lava as well as approximately 8 million tons of hydrogen fluoride and 120 million tons of sulfur dioxide. This eruption was known as the Síðueldur and Móðuharðindin (mist hardships), and was one of the greatest natural disasters the Northern Hemisphere has ever known.
Jón Steingrímsson, the parish priest and dean of Vestur-Skaftafellssýsla, desribed the waking nightmare as it first began:
This past week, and the two prior to it, more poison fell from the sky than words can describe: ash, volcanic hairs, rain full of sulfur and saltpeter, all of it mixed with sand. The snouts, nostrils, and feet of livestock grazing or walking on the grass turned bright yellow and raw. All water went tepid and light blue in color and gravel slides turned gray. All the earth’s plants burned, withered and turned gray, one after another, as the fire increased and neared the settlements.
Although 20 villages were destroyed by lava and hundreds perished in the initial blasts, the worst was yet to come. Roughly half of all the crops were destroyed and and estimated “80% of sheep, 50% of cattle and 50% of horses died because of dental fluorosis and skeletal fluorosis”, leading to state-wide famine that killed more than 9000 people … almost 1/4 of Iceland’s population.
The eruption also had global consequences, especially in neighboring Europe. A poisonousg of ash and gasses, propelled by unusually high temperatures in Iceland, spread across the UK and continental Europe, becoming known as the “Laki Haze”.
Not only did the fog harm crop yields and suppress trade, it carried lethal doses of sulphur dioxide gas for exposed to it too long. Sulphu dioxide “reacts with the moisture in lungs and produces sulfurous acid”, causing thousands of people to choke to death as soft tissue of their throat, trachea, and lungs swelled and filled. As many as 23,000 people died of the fog in just the UK. Worldwide figures must have edged toward the millions.
- The summer of the year 1783 was an amazing and portentous one, and full of horrible phaenomena; for besides the alarming meteors and tremendous thunder-storms that affrighted and distressed the different counties of this kingdom, the peculiar haze, or smokey fog, that prevailed for many weeks in this island, and in every part of Europe, and even beyond its limits, was a most extraordinary appearance, unlike anything known within the memory of man. By my journal I find that I had noticed this strange occurrence from June 23 to July 20 inclusive, during which period the wind varied to every quarter without making any alteration in the air. The sun, at noon, looked as blank as a clouded moon, and shed a rust-coloured ferruginous light on the ground, and floors of rooms; but was particularly lurid and blood-coloured at rising and setting. All the time the heat was so intense that butchers’ meat could hardly be eaten on the day after it was killed; and the flies swarmed so in the lanes and hedges that they rendered the horses half frantic, and riding irksome. The country people began to look, with a superstitious awe, at the red, louring aspect of the sun;
- … about six o’clock, that morning, I observed the air very much condensed in my chamber-window; and, upon getting up, was informed by a tenant that finding himself cold in bed, about three o’clock in the morning, he looked out at his window, and to his great surprise saw the ground covered with a white frost: and I was assured that two men at Barton, about 3 miles (4.8 km) off, saw in some shallow tubs, ice of the thickness of a crown-piece … The aristae of the barley which was coming into ear, became brown and withered at their extremities, as did the leaves of the oats; the rye had the appearance of being mildewed; so that the farmers were alarmed for those crops. The wheat was not much affected. The larch, Weymouth pine, and hardy Scotch fir, had the tips of their leaves withered.
Even after the fog dissipated, the ash and carbon dioxide rise in the atmosphere caused climatic conditions and extreme weather for the next three years, worsened by further eruptions at Grímsvötn from 1783 to 1785. Flooding and prolonged subzero winter temperatures killed thousands of people, and summer droughts brought subsequent famine that killed thousands more. The famine and extreme weather in France is probably what served as a tipping point for the French Revolution in 1789.
Europe would get hit by volcanic emissions again in 1816, the Year Without a Summer. The Regency era was a really bad time, via-a-vis volcanology.
Things would be almost as bad if another Laki-scale eruption happened in Iceland today. Although international shipping and global politics would probably address crop shortages, there is nothing anyone could do regarding deaths caused by extreme weather. Floods, hail, violent storms, tornadoes, hurricanes … all those would increase globally, just as they did in 1783/1784. Then there is the impact of the initial eruption. A similar outpouring of toxic effluvia would result in an estimated 142,000 people across Europe perishing from exposure to volcanic gasses.
The odds that there will never be another eruption on this scale are vanishingly small. The only question is WHEN this will happen.