Glacial period

A glacial period is an interval of time within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate within an ice age. The last glacial period ended about 10,000 to 15,000 years ago; the current Holocene epoch is the interglacial we are presently in.

Quaternary ice age

[
Pleistocene epoch within the Quaternary glaciation, as represented by atmospheric CO₂, measured from ice core samples going back 650,000 years]

Within the Quaternary glaciation (2.58 Ma to present), there have been various glacials and interglacials.

The Pleistocene extent of the Quaternary ice age, has been subdivided into the following stages.
*Bramertonian Stage
*Pre-Pastonian Stage
*Pastonian Stage
*Beestonian Stage
*Cromerian Stage
*Anglian Stage
*Hoxnian Stage
*Wolstonian Stage
*Eemian interglacial
*Last glacial period

Some of these stages, i.e. the Cromerian, Beestonian, and Wolstonian stages, consist of multiple glacial and interglacial periods. Other stages, the Anglian and Hoxnian stages, consist either of single glacial or interglacial periods.

Last glacial period

The last glacial period was the most recent glacial period within the current ice age, occurring in the Pleistocene epoch, which began about 70,000 and ended between 10,000 and 15,000 Before Present (BP). The glaciations that occurred during this glacial period covered many areas of the Northern Hemisphere, and have different names, depending on their geographic distributions: "Wisconsin" (in North America), "Devensian" (in the British Isles), "Midlandian" (in Ireland), "Würm" (in the Alps), "Weichsel" (in northern central Europe) and "Llanquihue" in Chile. The glacial advance reached its maximum extent about 18,000 BP. In Europe, the ice sheet reached northern Germany.

Next glacial period

Since orbital variations are predictable,cite journal | author=F. Varadi, B. Runnegar, M. Ghil | title=Successive Refinements in Long-Term Integrations of Planetary Orbits | journal=The Astrophysical Journal | volume=592 | year=2003 | pages=620–630 | url=http://astrobiology.ucla.edu/OTHER/SSO/SolarSysInt.pdf|doi=10.1086/375560] if one has a model that relates orbital variations to climate, it is possible to run such a model forward to "predict" future climate. Two caveats are necessary: that anthropogenic effects (global warming) are likely to exert a larger influence over the short term; and that the mechanism by which orbital forcing influences climate is not well understood.

Work by Berger and Loutre suggests that the current warm climate may last another 50,000 years.cite journal | author=Berger A, Loutre MF | title=Climate: An exceptionally long interglacial ahead? | journal=Science | volume=297 | issue=5585 | year=2002 | pages=1287–1288 | doi=10.1126/science.1076120 | pmid=12193773] .

ee also

* Glacier
* Geologic time scale
* Glacial history of Minnesota
* Milankovitch cycles
* Cyclostratigraphy
* Climate
* Precession (astronomy)
* Greenhouse and Icehouse Earth
* Snowball Earth
* Interglacial and Interstadial periods
* Yarkovsky effect
* YORP effect
* Quaternary glaciation
* last glacial period
* Last Glacial Maximum
* Ice age

References