Mount Tambora Eruption

In April 1815, Mount Tambora on the island of Sumbawa, in what is now Indonesia, erupted with a force unmatched in recorded history. The blast killed tens of thousands of people nearby, and the volcanic material it threw into the atmosphere cooled the global climate for a year or more. The summer of 1816, known in Europe and North America as the "Year Without Summer," brought crop failures and hunger far from the volcano itself.

Tambora was a large stratovolcano that had been dormant for centuries. It began to show signs of unrest a few years before the main event, and a smaller eruption occurred in the days before the climax. The region was then part of the Dutch East Indies trading world, with several small sultanates on Sumbawa and neighboring islands, such as Tambora, Sanggar, and Pekat, whose people farmed and traded in the shadow of the mountain.

The major eruption took place around 10 to 11 April. Explosions were heard hundreds of miles away, and accounts from the period describe ash falling across Java and beyond. Pyroclastic flows swept the slopes and entered the sea, and tsunamis struck nearby coasts. The mountain's summit collapsed, leaving a caldera several miles wide and reducing the peak's height by well over a thousand meters. Modern volcanologists rate the eruption a 7 on the Volcanic Explosivity Index, the largest in the last several centuries. The figure often cited for direct deaths is about 71,000, but estimates vary and the toll is uncertain. Many more people probably died from starvation and disease on Sumbawa and nearby Lombok in the following months, after crops and water supplies were ruined.

The eruption injected enormous quantities of sulfur gases into the stratosphere, forming aerosols that reflected sunlight. Global temperatures dropped by a fraction of a degree to roughly a degree Celsius, enough to disrupt growing seasons. In 1816 Europe saw cold, rainy weather, failed harvests, rising grain prices, and food riots. New England experienced unseasonable frosts. Monsoon patterns in South Asia were disrupted, and some historians link the disruption to severe famine and a cholera outbreak in Bengal, though the causal chain is debated.

Tambora's effects have also been tied to cultural moments. The gloomy summer kept Mary Shelley and her companions indoors beside Lake Geneva, where she began writing Frankenstein. Dramatic sunsets of the period may be reflected in the paintings of J.M.W. Turner, though that connection is speculative. Today, Tambora is studied as a key example of how a single eruption can ripple through climate, agriculture, and society worldwide.