In 1808, a massive volcano erupted somewhere on Earth. So large was the eruption that it bellowed sulfate particles into the atmosphere that caused significant global cooling in the years that followed (Guevara-Murua 2014). Despite its gargantuan size, nobody to this day has been able to locate the volcano or find any direct eyewitness accounts of its eruption. The volcanic eruption of 1808 remains an unresolved scientific mystery to this day.
How do we know this mystery volcano ever erupted at all? The first piece of evidence is an increase in sulfuric acid concentration found in Greenland ice cores, which are a characteristic ‘chemical signature’ of sulfur-rich volcanic eruptions (Dai 1991). The only major spike in sulfuric acid concentration in Greenland ice that doesn’t align with a real volcanic eruption observed somewhere on Earth is the spike found around 1808, suggesting the existence of this mysterious volcano.
The second piece of evidence is called the ‘sulfur isotope anomaly’. Deposits of sulfur buried deep underground have a different isotopic composition compared with sulfur sources on the planet’s surface. In the same way that we can monitor the effects of fossil fuel combustion on atmospheric concentrations of carbon dioxide, we can quantify the amount of sulfur emitted from volcanoes by measuring changes in the relative quantity of sulfur-33. A huge spike in Δ33S suggests an enormous volcanic eruption occurred – and that’s exactly what we see when we study samples from the year 1808.
The third piece of evidence comes from trees. Trees grow at different rates depending on the climate. In particular, trees grow faster when it’s warmer (but not too hot, of course, which inhibits their growth somewhat), and they grow more slowly when it’s cold. Counting tree rings can reveal not only the age of the tree, but measuring the thickness of each tree ring allows researchers to estimate the amount of growth the tree accomplished in a given year. By measuring different trees in the same region, researchers can gain insight into the past climate of that particular region. Analysis of tree rings has shown that bristlecone pine trees had drastically decreased growth rates in the summer of 1809, suggesting the climate cooled significantly around that time (Salzer 2007). Cooling might have been caused by a giant volcano.
While none of this evidence amounts to a direct observation that the mystery supervolcano ever erupted, we do have eyewitness accounts of volcanic ejecta from exactly the same time. All the evidence, taken together, definitely points to the fact that the supervolcano did in fact exist. Scientists, in fact, are certain.
The first eyewitness account was written a highly respected Colombian scientist called Francisco José de Caldas, who described “a transparent cloud that obstructs the sun’s brilliance” over Colombia for several months from December 1808 to February 1809. The second eyewitness was a physician named José Hipólito Unanue who wrote about seeing “sunset afterglows” over Peru in the same time period. Both these observations are characteristic of large volcanic eruptions.
The fact that atmospheric haze was observed in both Colombia and Peru, which are in the southern and northern hemispheres respectively, suggest that this volcano was located somewhere in the tropics. These observations imply that ash was cast 2,600 km in all directions but the effect on the climate was global. One researcher is quoted as saying the mystery volcano “blanketed the planet in ash”. (Cole-Dai n.d.)
Vulcanologists rate volcanic eruptions on a scale called VEI (volcanic explosivity index), which is similar to the Richter scale for earthquakes. It’s a logarithmic scale that approximates the volume of ash that’s ejected by a particular eruption. The logarithmic nature of the scale means that while a VEI-3 eruption is called “severe”, a VEI-4 event is called “cataclysmic”. In 2010, Eyjafjallajökull erupted in Iceland, resulting in ash cloud so large that it caused severe delays to air traffic across Europe, Greenland, Russia and eastern Canada. The Eyjafjallajökull eruption was a VEI-4 (“cataclysmic”) event.
When Mount Saint Helens erupted in 1908, killing 57 people and causing $1.1 billion of damage across Canada and the US, it was classified by vulcanologists as a VEI-5 (“paroxysmic”) event. Alarmingly, the mystery volcano in 1808 was at least 10 times more devastating than Mount Saint Helens in terms of the volume of ash ejected. The mystery volcano was a VEI-6 event, and it’s described by vulcanologists as “colossal”.
Volcanic ash acts “like a giant window shade, reflecting sunlight and lowering temperatures on the ground for years afterward” (Cole-Dai n.d.). Temperatures across Europe were measurably lower in the years that followed as the ash cloud obscured incoming rays from the sun. Trees grew more slowly (as evidenced by tree ring data), harvests were diminished and the climate cooled for several years afterwards.
This cooling came at a very inconvenient time. Temperatures were already lower than usual in the northern hemisphere due to the Little Ice Age. In a further devastating blow, a second, much larger volcano erupted on April 10, 1815. It was located on Mount Tambora in Indonesia and had an intensity of VEI-7 or “super-colossal” (this is just one level away from VEI-8, which is named rather horrifyingly, “apocalyptic”). Mount Tambora’s eruption was so ‘super-colossal’ that 90% of the islanders on Tambora were killed by lava flowing down from the sky. Downpours of hot ash killed trees and fish for miles around, covering them with inches of grey dust. Hot ejecta was propelled eighteen miles into the air above the volcano producing a ‘boom’ that could be heard a thousand miles away. People across Indonesia mistook the volcanic ‘boom’ for a ship’s rescue signal or a bomb detonation. Some army officials across Indonesia’s vast archipelago even dispatched troops to defend their islands after mistaking the ongoing volcanic roar for the sound of an invading army.
The sulfur dioxide released from the super-colossal Mount Tambora explosion reacted with gases in the stratosphere to produce 100 million tons of sulfuric acid, H2SO4. The sulfuric acid condensed and remained suspended in an ‘aerosol cloud’ (basically a cloud) that was accelerated by stratospheric jet streams (basically very strong winds) until the entire globe was smeared with a thin layer of H2SO4. This is a rare event, and only happens following truly colossal volcanic eruptions. Interestingly, H2SO4 reflects incoming rays from the sun, and temperatures, which were already low as a result of the mystery supervolcano in 1808, were lowered yet again. The year 1815 was, as some writers put it, “the year without a summer”. Temperatures that year were about three degrees lower than usual across Europe, which is incredible considering that both volcanoes erupted near the equator.
If the Mount Tambora volcano was a little smaller, the sulfuric acid would have formed in the atmosphere instead, and would have rained back down to the surface as acid rain. But at stratospheric altitudes, far above the clouds, the sulfuric acid haze stayed there for years acting as a kind of sunscreen for our planet.
How does this relate to chemophobia? The combination of the Little Ice Age, the 1808 mystery eruption and the super-colossal eruption of 1815 had cooled the climate to such an extent that the weather in Lake Geneva was terrible in the summer of 1815. Who was there at the time? Mary Shelley, of course, who was staying indoors drinking because the weather was too bad to go boating. Cold, bored and disappointed at the lack of a ‘summer’ holiday, Shelley and her companions set about writing ghost stories instead. Among them was Frankenstein, which featured the original, quintessential stereotype of a mad scientist. The cliché lives on to this day.