Glacial period: Difference between revisions

{{shortShort description|Interval of time within an ice age that is marked by colder temperatures and glacier advances}}

name="Severinghaus1999">{{cite journal |author1=J. Severinghaus |author2=E. Brook | title=Abrupt Climate Change at the End of the Last Glacial Period Inferred from Trapped Air in Polar Ice | journal=Science | volume=286 | year=1999 | pages=930–4 | doi=10.1126/science.286.5441.930 | pmid=10542141 | issue=5441}}</ref> The [[Holocene]] is the current interglacial. A time with no glaciers on Earth is considered a [[Greenhouse and icehouse Earth|greenhouse climate state]].<ref>{{cite journal |lastlast1= Bralower |firstfirst1= T.J.| last2= Premoli Silva| last3= Malone | first2= I. | first3= M.J. |editor3-first= M.J|editor3-last= Malone|editor2-first= I|editor2-last= Premoli Silva|editor1-first= T.J|editor1-last= Bralower|date= 2006|title= Leg 198 Synthesis : A Remarkable 120-m.y. Record of Climate and Oceanography from Shatsky Rise, Northwest Pacific Ocean |journal= Proceedings of the Ocean Drilling Program. Initial Reports|volume= 198|url=http://www-odp.tamu.edu/publications/198_IR/chap_01/chap_01.htm|publisher=Proceedings of the Ocean drilling program. |pages= 47 |doi= 10.2973/odp.proc.ir.198.2002|issn= 1096-2158|accessdateaccess-date= April 9, 2014|series= Proceedings of the Ocean Drilling Program}}</ref><ref>{{Cite journal

Within the [[Quaternary]], which started (about 2.6 million years [[annum|Ma]] tobefore present)]], there have been a number of glacials and interglacials.<ref name="ICSchart2013Gibbard">{{cite webbook |last1author1=CohenGibbard, |first1=K.MP. |last2author2=Finneyvan |first2=S.C.Kolfschoten, |last3=Gibbard |first3=P.LT. |last4chapter=FanChapter |first4=J.-X.22: |title=InternationalThe ChronostratigraphicPleistocene Chartand 2013Holocene Epochs |chapter-url=http://www-qpg.stratigraphygeog.orgcam.ac.uk/icschartpeople/chronostratchart2013-01gibbard/GTS2004Quat.pdf |websiteeditor1=stratigraphyGradstein, F. M.org |editor2=Ogg, James G. |editor3=Smith, A. Gilbert |title=A Geologic Time Scale 2004 |publisher=ICSCambridge University Press |accessdatelocation=7Cambridge January|year=2004 2019|refisbn=ICS2013978-0-521-78142-8}}</ref> At least eight glacial cycles have occurred in the last 740,000 years alone.<ref>{{Cite journal

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|Eemian interglacial]] interglacial.<ref>{{cite namejournal |last1=Nehme |first1=Carole |last2=Verheyden |first2=Sophie |last3=Breitenbach |first3=Sebastian F.M. |last4=Gillikin |first4=David P. |last5=Verheyden |first5=Anouk |last6=Cheng |first6=Hai |last7=Edwards |first7=R. Lawrence |last8=Hellstrom |first8=John |last9=Noble |first9=Stephen R. |last10=Farrant |first10=Andrew R. |last11=Sahy |first11=Diana |last12=Goovaerts |first12=Thomas |last13=Salem |first13=Ghada |last14=Claeys |first14=Philippe |display-authors=4|title="kanaan">Climate dynamicsDynamics duringDuring the penultimatePenultimate glacialGlacial periodPeriod recordedRecorded in a speleothemSpeleothem from Kanaan Cave, Lebanon (central Levant) |journal=Quaternary Research |date=July 2018 |volume=90 |issue=1 |pages=10–25 |doi=10.1017/qua.2018.18|bibcode=2018QuRes..90...10N |s2cid=134924228 |url=http://minerva.union.edu/gillikid/pdfs/Nehme_etal_2018_QR.pdf}}</ref>

The last glacial period was the most recent glacial period within the [[Quaternary glaciation]] [[Quaternaryat glaciation|Icethe Age]],end occurring inof the [[Pleistocene]] [[epoch (geology)|epoch]], whichand began about 110,000 years ago and ended about 1511,000700 years ago.<ref name="Severinghaus1999" /> The glaciations that occurred during thisthe 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]]), ''Weichsel'' (in northern [[centralCentral Europe]]), ''Dali'' (in [[East China]]), ''Beiye'' (in [[North China]]), ''Taibai'' (in [[Shaanxi]]) ''Luoji Shan'' (in Southwestsouthwest [[Sichuan]]), ''Zagunao'' (in Northwestnorthwest [[Sichuan]]), ''Tianchi'' (in the [[TianshanTian MountainsShan]]) ''QomolangmaJomolungma'' (in the [[HimalayaHimalayas]]), and ''Llanquihue'' (in [[Chile]]). The glacial advance reached itsthe [[Last Glacial Maximum|maximum extent]] about 26,500 [[Before Present|BP]]. In [[Europe]], the ice sheet reached [[Northern Germany]]. InOver the last 650,000 years, there were,have been on average, seven cycles of glacial advance and retreat.

{{seeSee also|Milankovitch cycles}}

Since orbital variations are predictable,<ref name="Varadi2003">{{cite journal|author1=F. Varadi |author2=B. Runnegar |author3=M. Ghil |author-link3=Michael Ghil |title=Successive Refinements in Long-Term Integrations of Planetary Orbits |journal=The Astrophysical Journal |volume=592 |issue=1 |year=2003 |pages=620–630 |url=http://astrobiology.ucla.edu/OTHER/SSO/SolarSysInt.pdf |doi=10.1086/375560 |bibcode=2003ApJ...592..620V |urldoi-statusaccess=dead |archiveurl=https://web.archive.org/web/20071128074218/http://astrobiology.ucla.edu/OTHER/SSO/SolarSysInt.pdf |archivedate=2007-11-28free }}</ref> computer models that relate orbital variations to climate can predict future climate possibilities.

Work by [[André Berger|Berger]] and Loutre suggests that the current warm climate may last another 50,000 years.<ref name="Berger2002">{{cite journal |vauthors=Berger A, Loutre MF | title=Climate: An exceptionally long interglacial ahead? | journal=Science | volume=297 | issue=5585 | year=2002 | pages=1287–8 | doi=10.1126/science.1076120 | pmid=12193773| s2cid=128923481 }}</ref> The amount of heat trapping (greenhouse) gases being emitted into the Earth's Oceansoceans and its atmosphere may delay the next glacial period by an additional 50,000 years.<ref name="LiveScience2007">{{cite webjournal |urllast1=https://www.livescience.com/1846-global-warming-good-news-ice-ages.htmlTyrrell|first1=Toby |title=GlobalCalcium WarmingCarbonate GoodCycling News:in NoFuture MoreOceans Iceand its Influence on Future Climates Ages|yearjournal=Journal of Plankton Research |date=16 November 2007 |publishervolume=LiveScience30 |issue=2 |pages=141–156 |doi=10.1093/plankt/fbm105|doi-access=free }}</ref><ref name="PIK2016">{{cite webjournal |urllast1=https://wwwGanopolski |first1=A.pik-potsdam |last2=Winkelmann |first2=R.de/news/press-releases/human-made-climate |author2-change-suppresses-the-next-ice-agelink=Ricarda Winkelmann |last3=Schellnhuber |first3=H. J. |title=Human-madeCritical climateInsolation–CO2 changeRelation suppressesfor theDiagnosing nextPast iceand Future Glacial Inception age|yearjournal=2016Nature |publisherdate=Potsdam14 InstituteJanuary for2016 Climate|volume=529 Impact|issue=7585 Research|pages=200–203 in|doi=10.1038/nature16494|pmid=26762457 |bibcode=2016Natur.529..200G |s2cid=4466220 Germany}}</ref>

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