1816 was a very bad year.
Across the entire Northern hemisphere, what would become known as The Year Without A Summer led to massive food shortages due to the overall drop in temperatures and the failure of food crops. Beginning in early spring, cool temperatures, fog, and heavy rains struck Europe, Asia, and North America leaving people mystified as to why this was happening.
The bizarre weather would extend into the following year with a bitterly cold winter in between. Famine broke out in many part of the world with food crises leading to massive strikes in numerous European cities. The price of many cereal crops rose to record highs as Europe would experience the last great famine of the 19th century. Temperatures were so cold that a massive ice dam formed in one region of Switzerland that would lead to massive flooding in 1818.
As for the cause of this strange change in the weather, that wouldn't become readily apparent until much later. While few people in the Northern hemisphere had even heard of Mount Tambora on the island of Sumbawa in the Indonesian archipelago, the massive eruption that occurred there on April 5, 1815 would eventually transform their lives.
That first volcanic blast would be so loud that Thomas Stamford Raffles, the lieutenant-governor of Java, would hear it eight hundred miles away. Along with other British authorities on the island, Raffles assumed that the sound came from gunfire. While nobody knew where the gunfire was coming from, military garrisons across Java went on alert. The British soldiers first suspected that a volcano was responsible when a light rain of ash fell on Java though nobody would realize the full magnitude of what was happening until later.
Meanwhile, Europe was preoccupied with other things. Napoleon's spectacular escape from Elba in February of 1815 and his brief attempt at regaining power led to a tense military confrontation that would end with the Battle of Waterloo on June 18, 1815. A relatively minor volcanic eruption would have gone completely unnoticed.
That is, until a far greater explosion occurred on April 10.
Now recognized as one of the greatest volcanic eruptions in recorded history, the eruption of Mount Tambora and the tsunamis it generated would kill tens of thousands as the top of the mountain was completely obliterated. Villages close to the site of the eruption were buried in pumice and ships that were hundreds of kilometers away were struck by hurricane-force winds. Of the 12,000 natives living near Tambora itself, there were only 100 known survivors. Were it not for a heavy rainstorm which struck the area on April 17, the death toll from the fires spread by the eruption might have been much higher.
Within twenty-four hours of the eruption, the cloud of ash from Tambora had grown to the size of Australia. Air temperatures dropped rapidly and many of the affected areas were littered by dead fish and birds. It was later estimated that the eruption had released one hundred cubic kilometers of molten rock into the atmosphere.
According to modern geologists rating the Tambora eruption on the Volcanic Explosivity Index (equivalent to the Richter scale for measuring earthquakes), the eruption of Mount Tambora is rated as 7 making it ten times stronger than the eruption at Krakatoa in 1883 and a hundred times stronger than the Mount St. Helens eruption in 1980. Only four other eruptions of the last 10,000 years have reached this intensity.
Many ships sailing through the area reported finding themselves in "utter darkness" due to the amount of ash that had been dispersed. Blotting out all sunlight, the ash covered many of the nearby islands to a depth of a meter. Ships had to zigzag through the local waters to avoid the clumps of floating cinders that had become a hazard to navigation.
It seemed fitting that the natives of many of the more distant islands assumed that the bizarre conditions they were experiencing were due to supernatural causes. Certainly a volcanic eruption of that magnitude had never occurred in living memory and Mount Tambora had been assumed to be extinct up to that time.
But the worst was still to come. The conditions produced by the eruption led to a failure of that year's crop leading to widespread famine. Another seventy to eighty thousand would die of famine or disease in Indonesia alone leading to a total death toll of ninety thousand overall in that one country. And the Year Without a Summer was only just beginning.
Along with millions of tons of ash, the Tambora eruption threw 55 million tons of sulphur-dioxide gas more than twenty miles into the stratosphere. Mixing with hydroxide, more than 100 million tons of sulfuric acid formed. The resulting aerosol cloud covered the entire equator in a matter of weeks and slowly spread to the North and South Poles as well. Suspended in the relatively stable upper stratosphere, the ashy remains of the Mount Tambora eruption would linger for years before dispersing. Nobody suspected then about the devastating impact this would have on the world's weather.
By December 1815, parts of Europe were noticing unusually severe snowstorms. Even more frigbtening was the colour of the snow in many places, ranging from red to yellow. The snow was described as "brick red and left an earthy powder, very light and impalpable, unctuous to the touch" as well as an "astringent taste." In Italy, religious processions were organized because the strange weather was believed to have been caused by God's wrath. Massive falls of red snow in Hungary caused the deaths of thousands of farm animals and the same was happening in other places as well.
While reports about the Mount Tambora eruption had slowly made their way to Western countries, nobody made the connection with the unusual weather conditions that were occurring. All that anyone knew for certain was that something very strange was happening and it was the lack of a rational explanation that helped feed into the sense of panic that was slowly brewing across much of the world.
While scientists have longed speculated on the "nuclear winter" scenario that might follow an all-out nuclear exchange, or possibly as the result of a large enough asteroid strike, what happened across much of the world in the years following the Mount Tambora eruption is a textbook example of how global cooling of even a few degrees can transform human life. Even though the cloud of ash and dust only reflected or scattered less thn one percent of the sunlight that reaches the Earth, it still devastated agriculture worldwide. But it was a gradual process for the most part. Despite the immediate darkening over much of the Indonesian archipelago right after the eruption, it would take up to a year for the full effects to be felt elsewhere. Since soil and ocean water can retain heat for long periods in spite of the cooler air passing over it, few people were aware that anything unusual was happening at first.
That is, except for the spectacular sunsets seen across the world in the summer and fall of 1815. In London, for example, observers noted the "sky exhibited in places a fire" with red, purple, and orange colours seen on the horizon as the sun set. Although the science that would explain the optical effects of the Tambora aerosol cloud in the atmosphere was still in its infancy, many letters written by London residents during this period mentioned the unusual optical effects. Not until the eruption of Krakatoa would such spectacular sunsets be seen again.
But the glorious sunsets were little consolation as the full impact of The Year Without A Summer became apparent. And the psychological toll was just beginning.