A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances.

Interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...

s, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago. The Holocene is the current interglacial. A time with no glaciers on Earth is considered a greenhouse climate state.

Quaternary Period

Within the Quaternary, which started about 2.6 million years

before present Before Present (BP) years, or "years before present", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Becaus ...

, there have been a number of glacials and interglacials. At least eight glacial cycles have occurred in the last 740,000 years alone.

Penultimate Glacial Period

The Penultimate Glacial Period (PGP) is the glacial period that occurred before the Last Glacial Period. It began about 194,000 years ago and ended 135,000 years ago, with the beginning of the Eemian interglacial.

Last Glacial Period

The last glacial period was the most recent glacial period within the Quaternary glaciation. It occurred in the Pleistocene, which began about 110,000 years ago and ended about 15,000 years ago. The glaciations that occurred during the glacial period covered many areas of the Northern Hemisphere and have different names, depending on their geographic distributions: ''Wisconsin'' (in North America), ''Devensian'' (in Great Britain), ''Midlandian'' (in Ireland), ''Würm'' (in the

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

), ''Weichsel'' (in northern

Central Europe Central Europe is an area of Europe between Western Europe and Eastern Europe, based on a common historical, social and cultural identity. The Thirty Years' War (1618–1648) between Catholicism and Protestantism significantly shaped the ar ...

), ''Dali'' (in

East China East China () is a geographical and a loosely defined cultural region that covers the eastern coastal area of China. A concept abolished in 1978, for economical purposes the region was defined from 1949 to 1961 by the Chinese Central Governme ...

), ''Beiye'' (in North China), ''Taibai'' (in Shaanxi) ''Luoji Shan'' (in southwest Sichuan), ''Zagunao'' (in northwest Sichuan), ''Tianchi'' (in the Tian Shan) ''Jomolungma'' (in the Himalayas), and ''Llanquihue'' (in

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

). The glacial advance reached the Last Glacial Maximum about 26,500 BP. In Europe, the ice sheet reached Northern Germany. Over the last 650,000 years, there have been on average seven cycles of glacial advance and retreat.

Next glacial period

Since orbital variations are predictable, computer models that relate orbital variations to climate can predict future climate possibilities. Work by

Berger Berger is a surname in both German and French, although there is no etymological connection between the names in the two languages. The French surname is an occupational name for a shepherd, from Old French ''bergier'' (Late Latin ''berbicarius'' ...

and Loutre suggests that the current warm climate may last another 50,000 years. The amount of heat trapping (greenhouse) gases being emitted into the Earth's oceans and its atmosphere may delay the next glacial period by an additional 50,000 years.

References

External links

{{DEFAULTSORT:Glacial Period

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...