I learned this today. The 1815 Mt. Tambora eruption lowered global temperatures and caused the Year Without a Summer.
Mt. Tambora is a volcano on the island of Sumbawa, which is in Indonesia these days. At the time of the eruption, the islands were controlled by the Dutch. The eruption reshaped the island and decimated its population.
Mt. Tambora has erupted four times since it formed about 500,000 years ago. In approximately 3910 BC, 3050 BC, 740 AD, and 1815. The results of the first three eruptions are unknown and the only way to know that there were eruptions is y radiocarbon dating.
The 1815 eruption occurred between April 5th and April 11th. The volcano had been dormant for several centuries, but by 1812 it had started to rumble and release a dark cloud.
On 5th April, 1815, an enormous eruption occurred. The sound of the eruption could be heard in Java, over 1200 km away. At 19:00 on April 10th, the eruption grew larger and three giant plumes of smoke and ash merged into one. The explosion was heard 2,600 km away and people thought guns were being fired.
The eruption reduced the height of the mountain by 1,200 m. 100km3 of ash and rock, about 10 billion tons, was blown over 40 km into the sky. Ash, pumice, and rocks up to 20 cm in size rained down on nearby islands. 100,000 people on the island of Sumbawa and nearby islands died as a result of the eruption. About a third of them died due to pyroclastic flows, ash and rock falls, and tsunamis, but the other two thirds died from hunger, disease, and respiratory problems caused by the ash. The volcano wiped out all of the wildlife on the island.
The mountain was swallowed in lava that superheated the air, causing it to rise quickly. Cooler air rushed in to fill the vacuum and created a whirlwind that tore up all of the trees, destroyed crops, flattened houses, and killed people and animals. This hot, rapidly rising air carried the ash cloud, which entered the stratosphere and was carried most of the way over the Northern Hemisphere. The larger pieces of ash rained out of the atmosphere over the following few weeks, but the finer particles stayed in the atmosphere for over a year at between 10 and 30 km. One of the effects of this was a series of brilliant sunsets viewed at different locations throughout the year. Paintings from this time show reds and oranges in the sky that were not there before the eruption. They are also much darker and moodier.
Mt. Tambora was a pretty stupendous volcanic eruption, but the effects on the world might not have been so bad if it hadn’t been for a series of other volcanoes that erupted at about that time. Between 1808 and 1814, five other volcanoes erupted. None of them were anywhere near as large as Tambora, but they may have added to the global problem.
The ash floating around in the atmosphere caused a volcanic winter. This is when the ash and droplets of sulfuric acid suspended in the atmosphere reflect more of the sun’s light away from the Earth, lowering average global temperatures.
In 1815, global temperatures dropped by 1℃. This might not sound like a lot, but it was enough to ruin world harvests and dramatically alter weather patterns. Many people feared that the apocalypse was coming.
Famines and floods occurred in many countries across Asia. The monsoon season was disrupted and frosts and even “summer snow” destroyed crops in China. In India, the floods killed crops and caused a cholera outbreak. In Europe, food shortages and floods led to riots and the spread of disease. The Napoleonic wars had just ended, and there were already food shortages that this situation exacerbated. There were typhus epidemics as well. In America, there were also food shortages as crops were ruined by floods and the cold weather. There was also a “dry fog” that hung around in parts of the eastern United States. It was red and wasn’t cleared by wind or rain. Temperatures fluctuated greatly in very short periods of time.
It took close to five years for everything to return to normal and it caused a lot of damage. The eruption may also have caused some longer reaching social and technological changes. When there are famines, people have to migrate in search of work and food. This event may have been the driving force to make Americans move and settle the center of the North American continent.
So, the eruption of Mt Tambora was the largest eruption in thousands of years. It blew billions of tons of rock and ash into the atmosphere that soon covered the globe and lowered world temperatures, changing weather patterns and killing crops. The resultant famines killed many people. And this is what I learned today.
Photo By NASA Expedition 20 crew. https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS020&roll=E&frame=06563
Sources:
https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora
https://en.wikipedia.org/wiki/Year_Without_a_Summer
https://en.wikipedia.org/wiki/Sumbawa
https://en.wikipedia.org/wiki/Mount_Tambora
https://www.smithsonianmag.com/history/blast-from-the-past-65102374/
https://www.nesdis.noaa.gov/news/day-history-mount-tambora-explosively-erupts-1815
https://www.wired.com/2015/04/tambora-1815-just-big-eruption/
https://en.wikipedia.org/wiki/Volcanic_winter
https://www.scientificamerican.com/article/1816-the-year-without-summer-excerpt/