Northern Hemispheric cooling period
The Late Antique Little Ice Age (LALIA) was a long-lasting Northern Hemispheric cooling period in the 6th and 7th centuries AD, during the period known as Late Antiquity. The period coincides with three large volcanic eruptions in 535/536, 539/540 and 547. The volcanic winter of 536 was the early phenomenon of the century-long global temperature decline. One study suggested a global cooling of 2 °C (3.6 °F).
The existence of a cooling period was proposed as a theory in năm ngoái, và subsequently confirmed as the period from 536 bự about 660 CE. [ tam ] Volcanic eruptions, meteorites striking the earth’s surface, & comet fragments exploding in the upper atmosphere have been proposed for the climatic cooling in 536 & afterwards. A problem is that no impact crater for a meteorite has been found, even though the land area và sea beds have been well surveyed for evidence. A comet fragment half a kilometer in kích cỡ exploding in the atmosphere could cause a plume of debris on the earth & create conditions for atmospheric cooling. [ bốn ] Most evidence, however, points Khủng volcanic eruptions occurring in 536, 540, & possibly 547, although the location of the volcano or volcanoes has not been determined. Locations such as Tavurvur in Papua New Guinea, Ilopango in El Salvador, và Krakatau in Indonesia have been proposed. [ 5 ]
Investigations in 2018 analyzed date calculator age
cores from glaciers in Switzerland & matched glass particles in the cores with volcanic rocks from Iceland, making the island nation a likely candidate for the source of the 536 eruption, although North America is also a possible location. [ 6 ] Evidence suggests that Ilopango in El Salvador was the source of the 539 / 540 eruption. Bipolar ice core investigations suggested that this eruption occurred in the tropics, và tree ring investigations near Ilopango found evidence of an eruption possibly in 540. However, a more recent study, examining other evidence, dated the eruption of Ilopango phệ the year 431, so sánh the issue remains unresolved. [ 2 ] [ 7 ] The eruption, whatever its location, put more aerosols into the atmosphere than the 1815 eruption of Mount Tambora, which caused the Year Without a Summer. [ tám ] Another eruption, location unknown, occurred in 547. [ 6 ] Additional evidence comes from a temperature reconstruction from the Euro-Med2k working nhóm of the international PAGES ( Past Global Changes ) project that used mới nhất tree-ring measurements from the Altai Mountains, which closely matches the temperatures in the Alps in the last two centuries. [ ba ] [ 9 ]The impact of the volcanic eruptions was the phenomenon known as volcanic winter. In the volcanic winter of 536, summer temperatures fell by as much as 2.5 degrees Celsius ( 4.5 degrees Fahrenheit ) below normal in Europe. ( ” Normal ” is considered by scientists Khủng be the average temperatures of the 1961 – 1990 period. ) The lingering impact of the volcanic winter of 536 was augmented in 539 – 540, when the second volcanic eruption caused summer temperatures bự decline as much as 2.7 degrees Celsius ( 4.9 degrees Fahrenheit ) below normal in Europe. [ 10 ]While the volcanic eruptions began the freeze, researchers think that increased ocean ice cover ( feedback Khủng the effects of the volcanoes ), coupled with an ” exceptional ” minimum of solar activity in the 600 s, reinforced và extended the cooling. [ 11 ] [ 12 ]According mập research by a đội from the Swiss Federal Research Institute at Birmensdorf, the fall in temperatures led béo the Arabian Peninsula experiencing a dramatic increase in fertility. [ 12 ] The boost of food supply contributed Khủng the Arab expansion beyond the peninsula in the Islamic conquests. The cooling period also led lớn increased strain on the Eastern Roman Empire và the Sassanid Empire, which helped the Muslim conquest of the Levant, the Muslim conquest of Egypt & the Muslim conquest of Persia. [ tam ]According mập research done by Israeli scientists, in 540, the kích thước of the population of the thành phố of Elusa, in the Negev Desert, và the amount of garbage that it generated started lớn shrink greatly. [ 13 ] Elusa housed tens of thousands of people during its height. [ 13 ] The major decline took place around the mid-6th century, about a century before the Islamic conquest. [ 14 ] One possible explanation for the crisis was the Late Antique Little Ice Age .The cooling period coincided with the Plague of Justinian, which began in 541, though the connection between the plague và the volcanoes still remains tenuous. The cooling period contributed phệ the migrations of the Lombards & the Slavs into Roman territory in Italy và the Balkans. [ ba ]