A volcanic winter is a reduction in global temperatures caused by volcanic ash and droplets of sulfuric acid and water obscuring the Sun and raising Earth's albedo (increasing the reflection of solar radiation) after a large, particularly explosive volcanic eruption. Long-term cooling effects are primarily dependent upon injection of sulfur gases into the stratosphere where they undergo a series of reactions to create sulfuric acid which can nucleate and form aerosols.Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation. The variations in atmospheric warming and cooling result in changes in tropospheric and stratospheric circulation.
The effects of volcanic eruptions on recent winters are modest in scale, but historically have been significant.
The causes of the population bottleneck – a sharp decrease in a species' population, immediately followed by a period of great genetic divergence (differentiation) among survivors – is attributed to volcanic winters by some researchers. Such events may diminish populations to "levels low enough for evolutionary changes, which occur much faster in small populations, to produce rapid population differentiation". With the Lake Toba bottleneck, many species showed massive effects of narrowing of the gene pool, and Toba may have reduced the human population to between 40,000 and 15,000 or even fewer.
Lake Toba is a large natural lake in Sumatra, Indonesia occupying the caldera of a supervolcano. The lake is located in the middle of the northern part of the island of Sumatra, with a surface elevation of about 900 metres (2,953 ft), the lake stretches fromto . The lake is about 100 kilometres long, 30 kilometres (19 mi) wide, and up to 505 metres (1,657 ft) deep. It is the largest lake in Indonesia and the largest volcanic lake in the world. Lake Toba Caldera is one of the nineteen Geoparks in Indonesia, which is proposed to be included in the UNESCO Global Geopark.
A supervolcano is a large volcano that has had an eruption with a Volcanic Explosivity Index (VEI) of 8, the largest recorded value on the index. This means the volume of deposits for that eruption is greater than 1,000 cubic kilometers.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
The Little Ice Age (LIA) was a period of cooling that occurred after the Medieval Warm Period. Although it was not a true ice age, the term was introduced into scientific literature by François E. Matthes in 1939. It has been conventionally defined as a period extending from the 16th to the 19th centuries, but some experts prefer an alternative timespan from about 1300 to about 1850.
The year 1816 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 (0.72–1.26 °F). This resulted in major food shortages across the Northern Hemisphere.
Mount Tambora, or Tomboro, is an active stratovolcano in the northern part of Sumbawa, one of the Lesser Sunda Islands of Indonesia. It was formed due to the active subduction zones beneath it, and before its 1815 eruption, it was more than 4,300 metres high, making it one of the tallest peaks in the Indonesian archipelago.
The Toba supereruption was a supervolcanic eruption that occurred about 75,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia. It is one of the Earth's largest known eruptions. The Toba catastrophe theory holds that this event caused a global volcanic winter of six to ten years and possibly a 1,000-year-long cooling episode.
The Yellowstone Caldera is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States, sometimes referred to as the Yellowstone Supervolcano. The caldera and most of the park are located in the northwest corner of Wyoming. The major features of the caldera measure about 34 by 45 miles.
Mount Tarawera is a volcano on the North Island of New Zealand. Located 24 kilometres southeast of Rotorua, it consists of a series of rhyolitic lava domes that were fissured down the middle by an explosive basaltic eruption in 1886. This eruption was one of New Zealand's largest historical eruptions, and killed an estimated 120 people. The fissures run for about 17 kilometres northeast-southwest.
Laki or Lakagígar is a volcanic fissure in the south of Iceland, not far from the volcanic fissure of Eldgjá and the small village of Kirkjubæjarklaustur. The fissure is properly referred to as Lakagígar, while Laki is a mountain that the fissure bisects. Lakagígar is part of a volcanic system centered on the volcano Grímsvötn and including the volcano Thordarhyrna. It lies between the glaciers of Mýrdalsjökull and Vatnajökull, in an area of fissures that run in a southwest to northeast direction.
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.
Huaynaputina is a stratovolcano in a volcanic upland in southern Peru. Part of the Central Volcanic Zone of the Andean Volcanic Belt, it is the product of the subduction of the oceanic Nazca tectonic plate beneath the continental part of the South American tectonic plate at a rate of 10.3 centimetres per year (4.1 in/year). Huaynaputina is a large volcanic crater, lacking an identifiable mountain profile, with an outer stratovolcano and three younger volcanic vents. The vents of Huaynaputina form a north-northwest–south-southeast trend.
El Chichón, also known as Chichonal, is an active volcano in Francisco León, north-western Chiapas, Mexico. El Chichón is part of a geologic zone known as the Chiapanecan Volcanic Arc. El Chichón is a complex of domes with a tuff ring, made of ejected volcanic material, located between the Trans-Mexican Volcanic Belt and the Central America Volcanic Arc. El Chichón erupted in 1982; prior to this, activity had not occurred since ca.1360, although debates in literature occur around an eruption occurring in ca.1850.
Stratospheric sulfur aerosols are sulfur-rich particles which exist in the stratosphere region of the Earth's atmosphere. The layer of the atmosphere in which they exist is known as the Junge layer, or simply the stratospheric aerosol layer. These particles consist of a mixture of sulfuric acid and water. They are created naturally, such as by photochemical decomposition of sulfur-containing gases, e.g. carbonyl sulfide. When present in high levels, e.g. after a strong volcanic eruption such as Mount Pinatubo, they produce a cooling effect, by reflecting sunlight, and by modifying clouds as they fall out of the stratosphere. This cooling may persist for a few years before the particles fall out.
This timeline of volcanism on Earth is a list of major volcanic eruptions of approximately at least magnitude 6 on the Volcanic Explosivity Index (VEI) or equivalent sulfur dioxide emission around the Quaternary period.
The 1815 eruption of Mount Tambora was the most powerful in human recorded history, with a Volcanic Explosivity Index (VEI) of 7. It is the most recently known VEI-7 event and the only unambiguously confirmed VEI-7 eruption since the Lake Taupo eruption in about 180 AD.
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.
In 1257, a catastrophic eruption occurred at Samalas 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 current Holocene epoch. It created eruption columns reaching tens of kilometres into the atmosphere and pyroclastic flows that buried much of Lombok and crossed the sea to reach the neighbouring island of Sumbawa. The flows destroyed human habitations, including the city of Pamatan, which was the capital of a kingdom on Lombok. Ash from the eruption fell as far as 340 kilometres (210 mi) away in Java; the volcano deposited more than 10 cubic kilometres (2.4 cu mi) of rocks and ash.