How Summer was Cancelled for a Year

by Paula Jatulan

While we welcomed 2020 with triumphant smiles and hopeful visions, it greeted us with a devastating news only a few days after. Mt. Taal started to act up. As the magma rises up, occurrences of earthquakes took place, with the volcano eventually spewing ash and lava to the Earth’s surface. When it calmed down, we were left with damaged properties and crops, fish kills, and uncertainty of where the year will be headed.

All of these resulted from an eruption of what is considered to be a small yet powerful volcano. But what happens if an eruption was caused by a volcano much bigger than Taal? Just up to what extent can it affect the planet?

1816 — The Year Without a Summer

Yes, that’s right. Summer of 1816 did not happen for the most parts of the Northern Hemisphere. Instead of playing in the pool or by the beach and having an ice-filled glass of juice to beat the scorching heat of the sun, people might’ve grabbed their coats and winter clothes as temperatures were 2°-4°C lower than usual in western and central Europe and western Mediterranean. On the other hand, the other parts of Europe were reported to have normal to slightly warmer summer temperatures. This was not the only unusual thing to happen that year as rainfall in some European countries were approximately twice the amount they should have received1.

Several weather data were retrieved from the logbooks of 227 ships, which documented the state of the global climate system for a period of three years. Together with the supplementary land-based data, some of the highlights of the world’s climate during 1815–172 were: (1) Asia winter and summer monsoons were strong enough to cause anomalous cold and near- or above-normal rains; (2) severe drought; and (3) anomalies of colder-than-normal extratropical temperatures and above-than-normal temperatures across the globe.

These widespread anomalies in the climate had, in no doubt, affected the people and other living things dramatically. Stunted growth of plants led to harvest failures, which led to famine1. For a long time, people weren’t able to identify the root cause of the unsettled weather patterns, and at some point, blamed the sunspots for it3. However, scientists have found a new link to explain why those bizarre things happened — the largest known volcanic eruption in recorded history.

The 1815 Onslaught

Located on the northern coast of Sumbawa Island, Indonesia, the infamous stratovolcano4 Mount Tambora (a.k.a Mount Tamboro or Gunung Tambora) stands at 2, 851 meters high. Its last known eruption was in 1967, but the 1815 one is what this volcano is notorious of. The summit elevation of Mt. Tambora used to be 4,300 m — the highest peak5 in the area — but the eruption in 1815 chipped most of its top off and left a caldera that is about 6 km6.

With a volcanic eruption index (VEI) of 6–77, this eruption is considered to be the most violent as it is approximately a thousand times stronger than the volcano Eyjafjallajökull in Iceland (which 2010 eruption was rated 4), a hundred times more powerful than Mt. St. Helens, and ten times more forceful than Krakatoa5.

Mt. Tambora’s eruptive activity started before the sunset of April 5, 1815 with minor and sporadic emissions of pyroclastic materials accompanied with a “short, high-intensity Plinian column8.” Plinian volcanic eruptions are the intense and violent kind characterized by volcanic fragments and gases being ejected out of a volcano upwards, the column reaching up to greater than 25 km above sea level9. Imagine a large rocket blasting to the space, the cloud of smoke it makes resemble the Plinian eruption clouds.

For two hours, the volcano’s magma chamber continued to let go a stream of lava onto the surface of the Earth. When all of these began, no one from afar might’ve suspected that a volcano was throwing fire and rocks somewhere. When Tambora erupted, it sounded like a cannon that was heard even in Java and so, this was what everyone thought. Soon after dawn, a light ashfall rained down on the region — a proof that somewhere, a volcano eruption made that sound. Only a few considered that it was Mt. Tambora as they thought a sound that massive should’ve come from a nearby volcano.

This continued on until around seven o’clock in the evening of April 10. The volcano has reached its climactic phase. It shot three blazing lava columns to the air. A high-intensity Plinian column was generated again; pumice rocks ranging from the size of a walnut to twice as much a human’s fist rained down on the nearby villages. Only an hour had passed when the darkness caused by ash and dust had devoured the atmosphere.

While the ashes continued to pile up in the sky, flaming lava flowing out of the volcano made the air above reach thousands of degrees Celsius. As the hot air rose, the cooler air that sunk down caused a whirlwind and took everything. The trees were ripped from their roots. Animals, people, and houses were swept up. The pumice rocks flooded in the proximal areas. Even the aquatic biosphere was not spared as the streams of lava slammed into the ocean. Consequently, tsunamis reaching ~4 m high gobbled everything in its path. The fiery lava meeting with cool seawater resulted in violent explosions, creating kilometers of pumice fields along the shoreline and more ash particles into the sky.

Mt. Tambora started to end the climax by having a huge chunk of its top blasted into pieces. The eruption drained the volcano’s magma chamber, causing it to collapse. A depression spanning around 6 km was left. Due to the eruption’s force, particles of ash, dust, and soot rose up to the sky, some might’ve even reached the stratosphere. The ash cloud became to look something like a mushroom or an umbrella as the larger particles of pyroclastic materials started to fall to the ground, while the smaller ones still settled up there.

Intermittent explosions persisted until the evening of April 11. The ash cloud continued to spread as far as it could, reaching Western Java, which is approximately 1, 300 km from Mt. Tambora. As the particles of ash rained down the region, it blocked out the sun as if it is spreading darkness all over the region5, 8.

The Aftermath

After Mt. Tambora had simmered down, the results of the havoc it wreaked were the proof of the most powerful volcanic eruption known in the human history. Ashes piled up to almost 40 inches in villages that were within a little over 30 km from the volcano, while eight to 10 inches of ash covered the areas over a hundred kilometer from the volcano. Crops and wildlife were ravaged. The blast, tsunamis, and whirlwinds, combined with the ~100 km3 of ash and rocks ejected out of the volcano devastated the homes of 35, 000 islanders or more. 10, 000 individuals died. A lot more perished out of starvation as their livelihood and sources of food were ruined5, 6.

Over time, scientists had proven, “with high statistical confidence10,” that this 1815 eruption of Mt. Tambora had a major contribution in the anomalous cold and wet conditions in the Northern Hemisphere in 1816. The volcano had released large amounts of silicon dioxide (SiO2) into the atmosphere, which had been transformed to sulphate aerosols. When those particles formed in the stratosphere lingered for years and as those aerosols warmed the stratosphere, they cooled the surface. Because of the global cooling, famine had persisted. Delays in the onset of plants’ growth were “record-breaking.” Harvested crops did not reach maturity, and just got rotten. Some of the goods’ prices rose up because of the crisis1.

To say that Mt. Tambora caused a major catastrophe is an understatement; it altered the course of the world. The way we lived changed drastically. It proved just how powerful volcanic eruptions can affect us and put us into the great sufferings. Fortunately for us, a VEI of 7 had a chance of occurring between one and two per thousand years11, but this doesn’t mean that we can afford to be lax. Although we have come so far and a lot of things had been progressive for us lately, science still continues to move forward as it still doesn’t have the absolute answer to all the questions. We can never really know for sure when will be the next volcanic eruption-induced climate change will happen. Adding a colossal eruption to all the things we had done so far to our planet, we might have years without summers.


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Bush, A. (2020). 1816: The year without a summer. Retrieved from

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Gertisser, R., Self, S., Thomas, L., Handley, H., Calsteren, P., & Wolff, J. (2012). Processes and timescales of magma genesis and differentiation leading to the great Tambora eruption in 1815. Journal of Petrology, 53(2), 271–297.

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Schurer, A., Hegerl, G, Luterbacher, J., Brönnimann, S., Cowan, T., Tett, S., Zanchettin, D., & Timmreck, C. (2019). Disentangling the causes of the 1816 European year without a summer. Environmental Research Letters, 14(9).

Florindo, F. (2018). Are we prepared for the next mega eruption?. Eos.



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