A volcanic winter is the reduction in temperature caused by volcanic ash and droplets of sulfuric acid obscuring the sun, usually after a volcanic eruption. Ash plume from Mt Cleveland, a stratovolcano Diamond Head, a well-known backdrop to Waikiki in Hawaii, is an ash cone that solidified into tuff Volcanic ash consists of very fine rock and mineral particles less than 2 mm in diameter that are ejected from a volcanic vent. ... Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. ... The Sun (Latin: Sol) is the star at the center of the Solar System. ... For other uses, see Volcano (disambiguation). ...

Effects on life

The causes of the bottleneck phenomenon, i.e., a sharp decrease in a species' population immediately followed by a period of great genetic divergence (differentiation) among survivors—might be attributed to volcanic winters. According to anthropologist Stanley Ambrose, such events diminish the population size to "levels low enough for evolutionary changes, which occur much faster in small populations, to produce rapid population differentiation". A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ... In biology, a species is one of the basic units of biodiversity. ... Differentiation can mean the following: In biology: cellular differentiation; evolutionary differentiation; In mathematics: see: derivative In cosmogony: planetary differentiation Differentiation (geology); Differentiation (logic); Differentiation (marketing). ... Anthropology (from Greek: ἀνθρωπος, anthropos, human being; and λόγος, logos, knowledge) is the comparative study of the physical and social characteristics of humanity through the examination of historical and present geographical distribution, cultural history, acculturation, and cultural relationships. ...

Ancient case of volcanic winters

One proposed volcanic winter happened around 71,000–73,000 years ago following the supereruption of Lake Toba on Sumatra island in Indonesia. In the following 6 years there was the highest amount of volcanic sulphur deposited in the last 110,000 years, possibly causing significant deforestation in Southeast Asia and the cooling of global temperatures by 1°C ^[1] . Some scientists hypothesize the eruption caused an immediate return to a glacial climate regime by accelerating an ongoing continental glaciation, thereby causing massive population reduction among animals and human beings on Earth. Others argue that the climatic effects of the eruption were insufficiently weak and brief to impact early human populations to the degree proposed ^[2] A supervolcano refers to a volcano that produces the largest and most voluminous kinds of eruption on Earth. ... View of Lake Toba Lake Toba is a large lake, 100km long and 30km wide, in the middle of the northern part of the Indonesian island of Sumatra. ... Sumatra (also spelled Sumatera) is the sixth largest island in the world (approximately 470,000 km²) and is the largest island entirely in Indonesia (two larger islands, Borneo and New Guinea, are partially in Indonesia). ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ... Deforestation is the conversion of forested areas to non-forest land use such as arable land, pasture, urban use, logged area or wasteland. ... Location of Southeast Asia Southeast Asia is a subregion of Asia. ... Fig. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ...

This, combined with the fact that most human differentiations abruptly occurred at that same period, is a probable case of bottleneck linked to volcanic winters (see Toba catastrophe theory). On average, super-eruptions with total eruptive masses of at least 10^15 kg (Toba eruptive mass=6.9*10^15 kg) occur every 1 million years ^[3] A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ... Eruption column rising, Mount Redoubt, Alaska According to the Toba catastrophe theory, modern human evolution was affected by a recent, large volcanic event. ...

Recent cases of volcanic winter

Pinatubo early eruption 1991

The scales of recent winters are more modest but their effects can be significant. A paper written by Benjamin Franklin in 1783 blamed the unusually cool summer of 1783 on volcanic dust coming from Iceland, where the eruption of Laki volcano had released enormous amounts of sulfur dioxide, resulting in the death of much of the island's livestock and a catastrophic famine which killed a quarter of the population. Temperatures in the northern hemisphere dropped by about 1°C in the year following the Laki eruption. Photo: T. J. Casadevall, U.S. Geological Survey. ... Photo: T. J. Casadevall, U.S. Geological Survey. ... Benjamin Franklin (January 17 [O.S. January 6] 1706 – April 17, 1790) was one of the most well known Founding Fathers of the United States. ... 1783 was a common year starting on Wednesday (see link for calendar). ... The name Laki has more than one meaning:- A town called Laki in Plovdiv district in Bulgaria. ... Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ... Sheep are commonly bred as livestock. ... A famine is a social and economic crisis that is commonly accompanied by widespread malnutrition, starvation, epidemic and increased mortality. ... The Northern Hemisphere is the half of a planets surface (or celestial sphere) that is north of the equator (the word hemisphere literally means half ball). On the Earth, the Northern Hemisphere contains most of the land and about 88-90% of the human population. ...

The 1815 eruption of Mount Tambora, a stratovolcano in Indonesia, occasioned mid-summer frosts in New York State and June snowfalls in New England in what came to be known as the "Year Without a Summer" of 1816. April 5-12: Mount Tambora explodes, changing climate. ... Mount Tambora (or Tomboro) is an active stratovolcano on Sumbawa island, Indonesia. ... A cutaway diagram of a stratovolcano Mount Damavand, a stratovolcano in Māzandarān, Iran Mount St. ... State nickname: Empire State Other U.S. States Capital Albany Largest city New York Governor George Pataki Official languages None Area 141,205 km² (27th)  - Land 122,409 km²  - Water 18,795 km² (13. ... This article is about the region in the United States of America. ... Development of global average temperatures during the last 1000 years. ... 1816 was a leap year starting on Monday (see link for calendar). ...

In 1883, the explosion of Krakatoa (Krakatau) also created volcanic winter-like conditions. The next four years after the explosion were unusually cold, and the winter of 1888 was the first time snow fell in the area. Record snowfalls were recorded worldwide. 1883 (MDCCCLXXXIII) was a common year starting on Monday (see link for calendar). ... Krakatoa or Krakatau or Krakatao is a volcanic island in the Sunda Strait between Java and Sumatra in Indonesia. ... Year 1888 (MDCCCLXXXVIII) was a leap year starting on Sunday (click on link for calendar) of the Gregorian calendar (or a leap year starting on Tuesday of the 12-day slower Julian calendar). ...

Most recently, the 1991 explosion of Mount Pinatubo, another stratovolcano, in the Philippines cooled global temperatures for about 2-3 years. 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... Mount Pinatubo is an active stratovolcano located on the island of Luzon in the Philippines, at the intersection of the borders of the provinces of Zambales, Tarlac, and Pampanga. ...

References

Further reading

• MR Rampino, S Self & RB Stothers (1988). "Volcanic winters". Annual Review of Earth and Planetary Science 16: 73-99. DOI:10.1146/annurev.ea.16.050188.000445. 

• C. Oppenheimer, 2002, Limited global change due to the largest known Quaternary eruption, Toba ~~ 74 Kyr BP, Quaternary Science Reviews, 21, 1593-1609.

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

See also

• Nuclear winter
• Climate changes of 535-536
• Year Without a Summer