The 1808 mystery eruption is one or potentially multiple unidentified volcanic eruptions that resulted in a significant rise in stratospheric sulfur aerosols, leading to a period of global cooling analogous to the Year Without a Summer in 1816. [2] [3] [4]
Until the 1990s, climatologists considered the known deterioration of the weather in the early 1810s as a normal phenomenon of the Little Ice Age. A 1991 study of Antarctic and Greenland ice cores, however, found a sulfate spike in early 1809, roughly half that of the 1815 eruption of Mount Tambora. [5] This faced volcanologists with the problem that this period has no recorded eruptions of the needed magnitude to generate such a spike. [6] Further research and bristlecone pine tree ring data pointed to the eruption being in 1808 rather than early 1809. [7]
Initially believed to be a single VEI-6 eruption, emerging evidence suggests that the rise in sulfate concentration and global cooling was likely caused by a series of eruptions, including some minor ones. [8] [2] [9]
Compilations of the geochemistry of tephras found at the corresponding sulfate layer in ice cores indicate multiple eruptions around this time, including a probable Antarctic source, an Alaskan source and Indonesian source. This led to the possibility that the massive 1809 sulfate spike was generated by a combination of tropical and extra-tropical eruptions occurring in short succession rather than a single large volcanic eruption. [2] [8]
The analysis of sulfur isotopes shows a complex time-evolving pattern, suggesting multiple eruptions that caused the 1809 sulfate layer and global cooling, consistent with the presence of different geochemical tephra populations during this period. [9]
The expectation that any eruptions of that magnitude should have been noticed at the time added to the mystery. Records from the time throughout the world were checked but nothing appeared viable until the summer of 2014, when PhD student Alvaro Guevara-Murua and Caroline Williams of the University of Bristol discovered an account of atmospheric events consistent with such an event by Colombian scientist Francisco José de Caldas.
Caldas served as Director of the Astronomical Observatory of Bogotá between 1805 and 1810 and in 1809 reported a "transparent cloud that obstructs the sun's brilliance" at Bogotá. It had first been observed by him on 11 December 1808 and was visible across Colombia. [4] The cloud might have been a "dry fog", which is a sulfuric acid (H2SO4) aerosol. [4] He also reported that the weather had been unusually cold, with frosts.
To the south, in Peru, physician Hipólito Unanue made similar observations in Lima. [4] These reports led those involved to suggest that the window of the eruption was within seven days of 4 December 1808. [4] Caldas' and Unanue's accounts indicated the existence of a stratospheric aerosol veil spanning at least 2,600 kilometres (1,600 mi) into both northern and southern hemispheres. The only likely source for this would be a tropical volcano, most likely located in the southern hemisphere but not likely further than 20 degrees south latitude. [4]
The south-western Pacific Ocean between Indonesia and Tonga is an area in the tropics to the west of Colombia and Peru with candidate volcanoes and with little reporting at that time. This area had no European settlements at the time, and most of the reporting on its volcanic activity goes back only to the mid-19th century, apart from the occasional sighting by passing European explorers. [10] The region includes the Rabaul area, which has had VEI 6 eruptions, as well as the Hunga Tonga–Hunga Haʻapai area which had a VEI 5–6 eruption in 2022. [11] The oral histories of the indigenous populations of these areas report eruptions, but these could not be dated with any degree of certainty. [12]
In 1808 there were major eruptions in Urzelina, Azores, on 1–4 May, and in Taal Volcano, Philippines, in March. [13] Neither of these occurred within the correct time period for the visual observations.
The Chilean Putana volcano also had a major eruption around this time, with an approximate date of 1810 (with a 10-year margin of error), but it is located 22 degrees south and therefore slightly outside the preferred latitude range. [14]
The volcanic explosivity index (VEI) is a relative measure of the explosiveness of volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982.
The year 1816 AD is known as the Year Without a Summer because of severe climate abnormalities that caused average global temperatures to decrease by 0.4–0.7 °C (0.7–1 °F). Summer temperatures in Europe were the coldest of any on record between 1766 and 2000, resulting in crop failures and major food shortages across the Northern Hemisphere.
Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, it was formed by the active subduction zones beneath it. Before 1815, its elevation reached more than 4,300 metres high, making it one of the tallest peaks in the Indonesian archipelago.
A volcanic winter is a reduction in global temperatures caused by droplets of sulfuric acid obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, sulfur-rich, particularly explosive volcanic eruption. Climate effects are primarily dependent upon the amount of injection of SO2 and H2S into the stratosphere where they react with OH and H2O to form H2SO4 on a timescale of a week, and the resulting H2SO4 aerosols produce the dominant radiative effect. Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation for several years. Moreover, the cooling trend can be further extended by atmosphere–ice–ocean feedback mechanisms. These feedbacks can continue to maintain the cool climate long after the volcanic aerosols have dissipated.
Plinian eruptions or Vesuvian eruptions are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD, which destroyed the ancient Roman cities of Herculaneum and Pompeii. The eruption was described in a letter written by Pliny the Younger, after the death of his uncle Pliny the Elder.
Trachyandesite is an extrusive igneous rock with a composition between trachyte and andesite. It has little or no free quartz, but is dominated by sodic plagioclase and alkali feldspar. It is formed from the cooling of lava enriched in alkali metals and with an intermediate content of silica.
Kuwae was a landmass that existed in the vicinity of Tongoa and was destroyed by volcanic eruption in fifteenth century, probably through caldera subsidence. The exact location of the caldera is debated. A submarine caldera, now known as Kuwae caldera that is located between the Epi and Tongoa islands is a potential candidate. Kuwae Caldera cuts through the flank of the Tavani Ruru volcano on Epi and the northwestern end of Tongoa. Another potential candidate is a proposed caldera between Tongoa and Tongariki.
Stratospheric aerosol injection is a proposed method of solar geoengineering to reduce global warming. This would introduce aerosols into the stratosphere to create a cooling effect via global dimming and increased albedo, which occurs naturally from volcanic winter. It appears that stratospheric aerosol injection, at a moderate intensity, could counter most changes to temperature and precipitation, take effect rapidly, have low direct implementation costs, and be reversible in its direct climatic effects. The Intergovernmental Panel on Climate Change concludes that it "is the most-researched [solar geoengineering] methodagreement that it could limit warming to below 1.5 °C (2.7 °F)." However, like other solar geoengineering approaches, stratospheric aerosol injection would do so imperfectly and other effects are possible, particularly if used in a suboptimal manner.
Hunga Tonga–Hunga Haʻapai is a submarine volcano in the South Pacific located about 30 km (19 mi) south of the submarine volcano of Fonuafoʻou and 65 km (40 mi) north of Tongatapu, Tonga's main island. It is part of the highly active Kermadec-Tonga subduction zone and its associated volcanic arc, which extends from New Zealand north-northeast to Fiji, and is formed by the subduction of the Pacific Plate under the Indo-Australian Plate. It lies about 100 km (62 mi) above a very active seismic zone.
This timeline of volcanism on Earth includes a list of major volcanic eruptions of approximately at least magnitude 6 on the Volcanic explosivity index (VEI) or equivalent sulfur dioxide emission during the Quaternary period. Other volcanic eruptions are also listed.
Mount Tambora is a volcano on the island of Sumbawa in present-day Indonesia, then part of the Dutch East Indies, and its 1815 eruption was the most powerful volcanic eruption in recorded human history. This volcanic explosivity index (VEI) 7 eruption ejected 37–45 km3 of dense-rock equivalent (DRE) material into the atmosphere, and was the most recent confirmed VEI-7 eruption.
Tectonic–climatic interaction is the interrelationship between tectonic processes and the climate system. The tectonic processes in question include orogenesis, volcanism, and erosion, while relevant climatic processes include atmospheric circulation, orographic lift, monsoon circulation and the rain shadow effect. As the geological record of past climate changes over millions of years is sparse and poorly resolved, many questions remain unresolved regarding the nature of tectonic-climate interaction, although it is an area of active research by geologists and palaeoclimatologists.
Explosive volcanic eruptions affect the global climate in several ways.
In 1257, a catastrophic eruption occurred at Samalas, a volcano on the Indonesian island of Lombok. The event had a probable Volcanic Explosivity Index of 7, making it one of the largest volcanic eruptions during the Holocene epoch. It left behind a large caldera that contains Lake Segara Anak. Later volcanic activity created more volcanic centres in the caldera, including the Barujari cone, which remains active.
There are two large sulfate spikes caused by mystery volcanic eruptions in the mid-1400s: the 1452/1453 mystery eruption and 1458 mystery eruption. Before 2012, the date of 1458 sulfate spike was incorrectly assigned to be 1452 because previous ice core work had poor time resolution. The exact location of this eruption is uncertain, but possible candidates include the submerged caldera of Kuwae in the Coral Sea, Mount Reclus and Tofua caldera. The eruption is believed to have been VEI-7.
Little Ice Age volcanism refers to the massive volcanic activities during the Little Ice Age. Scientists suggested a hypothesis that volcanism was the major driving force of the global cooling among the other natural factors, i.e. the sunspot activities by orbital forcing and greenhouse gas. The Past Global Change (PAGES), a registered paleo-science association for scientific research and networking on past global changes in the University of Bern, Switzerland, suggested that from 1630 to 1850, a total of 16 major eruptions and cooling events had taken place. When a volcano erupts, ashes burst out of the vent together with magma and forms a cloud in the atmosphere. The ashes act as an isolating layer that block out a proportion of solar radiation, causing global cooling. The global cooling effect impacts ocean currents, atmospheric circulation and cause social impacts such as drought and famine. Wars and rebellions were therefore triggered worldwide in the Little Ice Age. It was suggested that the crisis on Ottoman Empire and Ming-Qing Transition in China were typical examples that closely correlated with Little Ice Age.
In December 2021, an eruption began on Hunga Tonga–Hunga Haʻapai, a submarine volcano in the Tongan archipelago in the southern Pacific Ocean. The eruption reached a very large and powerful climax nearly four weeks later, on 15 January 2022. Hunga Tonga–Hunga Haʻapai is 65 kilometres (40 mi) north of Tongatapu, the country's main island, and is part of the highly active Tonga–Kermadec Islands volcanic arc, a subduction zone extending from New Zealand to Fiji. On the Volcanic Explosivity Index scale, the eruption was rated at least a VEI-5. Described by scientists as a "magma hammer", the volcano at its height produced a series of four underwater thrusts, displaced 10 cubic kilometres (2.4 cu mi) of rock, ash and sediment, and generated the largest atmospheric explosion recorded by modern instrumentation.
The 1452/1453 mystery eruption is an unidentified volcanic event that triggered the first large sulfate spike in the 1450s, succeeded by another spike in 1458 caused by another mysterious eruption. The eruption caused a severe volcanic winter leading to one of strongest cooling events in the Northern Hemisphere. This date also coincides with a substantial intensification of the Little Ice Age.