Lately I’ve been thinking about the weather. For one thing, it’s hot as blue blazes here in East Tennessee. The cicada chirping has ceased, thus bringing an end to the dog days of summer, but it remains hot and dry, despite the fact that today is the first day of fall (or autumn, as they say in England). For another, I finished reading Tessa Harris’s third book in her Dr. Thomas Silkstone Mysteries series titled The Devil’s Breath.
The Great Fogg of 1783
The title of Harris’s book refers to the Great Fogg of 1783, which proved to be as interesting a protagonist as Dr. Silkstone himself. The Great Fogg rolled over Britain in the summer months, turning the air hazy and the sun blood red, spawning violent thunderstorms tainted with sulfur dioxide gas, and raining large hail. Harris wrote in her editor’s notes that roughly 80% of sheep and 50% of horses and cattle are believed to have died. The death rate in Britain rose by nearly 17% by the end of the year. The cause? A rupture of the Laki fissure in Iceland on July 8, which ejected huge amounts of basalt lava and toxic gases into the atmosphere. The dreadful foggy summer was followed by one of the coldest winters on record. In the US, the winter that followed the eruption was long and very cold. Even the harbor of Charleston, NC, felt its effects: people skated on its frozen waters!
Laki fissure in Iceland, considerably calmer than in 1783 (Source: Wikimedia Commons)
1816: The Year without a Summer
In April 1815, the volcano Mount Tambora erupted on Sumbawa Island, at that time considered a part of the Dutch East Indies (now Indonesia). The eruption continued for two weeks and caused the average global temperature to decrease 0.7-1.3°F over the next three years. The eruption produced severe disruptions in weather patterns; the cooler temperatures caused crop failures and famine and resulted in the deaths of some 100,000 people worldwide.
Tambora volcano on Indonesia’s Sumbawa Island (Source: Wikimedia Commons)
London Had Lower than Normal Temperatures in 1816
I happen to be working on my third novel, which features a Regency surgeon operating, quite literally, in the spring and summer of 1816. In carrying out my research I consulted the meteorological tables for the months of March through September in The Gentleman’s Magazine to obtain information about the weather conditions during that time period. After reading the Wikipedia entry about The Year without a Summer, I decided to go back through the magazine’s tables and calculate the mean temperature for each month, choosing the highest temperature during the day (typically the temperature shown at noon) and the number of days shown as “rainy” or “showery.” I then compared these 1816 figures to those shown on Wikipedia for England’s weather averages based on the years 1981-2010.
At first glance the temperatures looked much the same between the two sources. But then I calculated the averages. The average temperature for the months of May through September of 1816 was 62.6°F; for the same months in recent years (on Wikipedia), 65.8°F — a difference of 3.2°F.
The number of days of rain also differed. The average number for May through September, 1816, was 11.4 days; the contemporary figures on Wikipedia, 9.8 days — a difference of 1.6 days of rain.
In short, the meteorological tables published in The Gentleman’s Magazine for 1816 show an average temperature for the months of May through September that were 3.2°F lower than the average shown for the same months in the years 1981-2010 on Wikipedia. And it rained more frequently in the summer of 1816 than it does on average in England.
This seems like much ado about nothing until one looks at when the rain occurred. Most British farmers in 1816 would begin planting their wheat, barley, and oats in late May and early June. The crops ripened over the warm months of June and July and were ready for harvest in August or September. But there were two problems that summer of 1816. First, the temperature was colder than normal; and secondly, there was considerably more rain in July of 1816. In fact, in July The Gentleman’s Magazine reported 20 days of rain—twice the usual number. So, at a time when farmers were expecting their crops to mature, the constant rain prevented the crops from developing properly and, thus, the harvest failed.
Consequences of the Year without a Summer
The eruption caused what today we call a volcanic winter. (In truth, it also caused a volcanic summer!) Here are a few consequences of the Year without a Summer:
- Unusually low temperatures caused crop failures that in turn led to food shortages and famine across England, Ireland and Europe.
- The high amount of tephra thrown into the atmosphere during the volcanic eruption led to glorious sunsets, which may have influenced the painter J. M. W. Turner. His painting of the Chichester Canal is shown below.
Chichester Canal (1828), painted by J.M.W. Turner, may have been influenced by the spectacular sunsets following the eruption of Mount Tambora in 1815 (Wikimedia Commons)
- In June of 1816 Mary Shelley (née Godwin, daughter of Mary Wollstonecraft) and her lover Percy Bysshe Shelley stayed with Lord Byron at his rented house, Villa Diodati (near Lake Geneva, Switzerland). Because the summer was exceptionally rainy, the cozy group stayed frequently indoors, amusing themselves by reading German ghost stories. They decided to have a contest to see who could write the scariest ghost story. Mary Shelley wrote Frankenstein: Or, The Modern Prometheus—a tale that thrills readers even today.
Could we experience similar volcanic winters and summers today? Absolutely. Check out this site that shows the active volcanoes around the world. A Google search will give you plenty to look up if you, like me, are fascinated by volcanoes.
Additional Information:
1Quite possibly everything you’d care to know about the science of the Tambora volcano eruption can be found in this elegant, fact-filled booklet: Brönnimann S, Krämer D. 2016. Tambora and the “Year without a Summer” of 1816. A Perspective on Earth and Human Systems Science. Geographica Bernensia G90, 48 pp., doi:10:4480/GB2016.G90.01. (available here as a PDF)
2Here’s a recent paper showing the results of a reanalysis of the weather during the summer of 1816. The authors’ data confirm the link between severe weather and its effects on humans: Brohan P, Compo GP, Brönnimann S, et al. The 1816 ‘year without a summer’ in an atmospheric reanalysis. Clim Past Discuss. Published 12 July 2016. doi:10.5194/cp-2016-78, 2016. (a PDF version can be found here)