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La piccola era glaciale (in francese petit âge glaciaire; in inglese little Ice Age) o PEG è un periodo della storia climatica della Terra che, pur senza una totale convergenza degli studi, va approssimativamente dalla metà del XIV alla metà del XIX secolo nel quale si registrò un sensibile abbassamento della temperatura media ...
The Little Ice Age, by the anthropologist Brian Fagan of the University of California at Santa Barbara, describes the plight of European peasants from 1300 to 1850: famines, hypothermia, bread riots and the rise of despotic leaders brutalizing an increasingly dispirited peasantry.
Proxy records showed that mountain glaciers grew during the Little Ice Age at several locations—including the European Alps, New Zealand, Alaska, and the southern Andes—and mean annual temperatures across the Northern Hemisphere fell by 0.6 °C (1.1 °F) relative to the average temperature between 1000 and 2000 CE.
- John P. Rafferty
- Overview
- Geographic extent
- Effects on civilization
- Causes
- Variability in solar output
Little Ice Age (LIA), climate interval that occurred from the early 14th century through the mid-19th century, when mountain glaciers expanded at several locations, including the European Alps, New Zealand, Alaska, and the southern Andes, and mean annual temperatures across the Northern Hemisphere declined by 0.6 °C (1.1 °F) relative to the average...
Information obtained from “proxy records” (indirect records of ancient climatic conditions, such as ice cores, cores of lake sediment and coral, and annual growth rings in trees) as well as historical documents dating to the Little Ice Age period indicate that cooler conditions appeared in some regions, but, at the same time, warmer or stable conditions occurred in others. For instance, proxy records collected from western Greenland, Scandinavia, the British Isles, and western North America point to several cool episodes, lasting several decades each, when temperatures dropped 1 to 2 °C (1.8 to 3.6 °F) below the thousand-year averages for those areas. However, these regional temperature declines rarely occurred at the same time. Cooler episodes also materialized in the Southern Hemisphere, initiating the advance of glaciers in Patagonia and New Zealand, but these episodes did not coincide with those occurring in the Northern Hemisphere. Meanwhile, temperatures of other regions of the world, such as eastern China and the Andes, remained relatively stable during the Little Ice Age.
Still other regions experienced extended periods of drought, increased precipitation, or extreme swings in moisture. Many areas of northern Europe, for instance, were subjected to several years of long winters and short, wet summers, whereas parts of southern Europe endured droughts and season-long periods of heavy rainfall. Evidence also exists of multiyear droughts in equatorial Africa and Central and South Asia during the Little Ice Age.
The Little Ice Age is best known for its effects in Europe and the North Atlantic region. Alpine glaciers advanced far below their previous (and present) limits, obliterating farms, churches, and villages in Switzerland, France, and elsewhere. Frequent cold winters and cool, wet summers led to crop failures and famines over much of northern and central Europe. In addition, the North Atlantic cod fisheries declined as ocean temperatures fell in the 17th century.
During the early 15th century, as pack ice and storminess increased in the North Atlantic, Norse colonies in Greenland were cut off from the rest of Norse civilization; the western colony of Greenland collapsed through starvation, and the eastern colony was abandoned. Iceland became increasingly isolated from Scandinavia when the southern limit of sea ice expanded to encapsulate the island and locked it in ice for longer and longer periods during the year. Sea ice grew from zero average coverage before the year 1200 to eight weeks in the 13th century and 40 weeks in the 19th century.
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The cause of the Little Ice Age is not known for certain; however, climatologists contend that reduced solar output, changes in atmospheric circulation, and explosive volcanism may have played roles in bringing about and extending the phenomenon.
It has long been understood that low sunspot activity is associated with lower solar output and thus less energy available to warm Earth’s surface. Two periods of unusually low sunspot activity are known to have occurred within the Little Ice Age period: the Spörer Minimum (1450–1540) and the Maunder Minimum (1645–1715). Both solar minimums coincid...
The Effects of the Little Ice Age (c. 1300-1850) The Little Ice Age was a period of wide-spread cooling that lasted from the end of the Medieval Warm Period early in the 14 century, until the present-day warming trend that started in the middle to late 19th century (graph below).
3 giorni fa · La Piccola Era Glaciale (in inglese, Little Ice Age) è un periodo di tempo che va dai primi del 1300 al 1850 circa, caratterizzato da un abbassamento delle temperature medie e da inverni molto rigidi in tutto l’emisfero boreale.
9 feb 2016 · Attorno a 1500 anni fa ci sarebbe stato un periodo di raffreddamento dell’emisfero settentrionale senza precedenti, ribattezzato Piccola Era Glaciale Tardo Antica (In Inglese LALIA: Late Antique Little Ice Age). L’abbassamento delle temperature seguì tre grandi eruzioni, verificatesi nel 536, nel 540 e nel 547*.
