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235:, "since 1979, winter Arctic ice extent has decreased about 4.2 percent per decade". Both 2008 and 2009 had a minimum Arctic sea ice extent somewhat above that of 2007. At other times of the year the ice extent is still sometimes near the 1979–2000 average, as in April 2010, by the data from the National Snow and Ice Data Center. Still, between these same years, the overall average ice coverage appears to have declined from 8 million km to 5 million km.
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the last 100 years." In
September 2012, sea ice reached its smallest size ever. Journalist John Vidal stated that sea ice is "700,000 sq km below the previous minimum of 4.17m sq km set in 2007". In August 2013, Arctic sea ice extent averaged 6.09m km, which represents 1.13 million km below the 1981–2010 average for that month.
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The current rate of decline of the ice caps has caused many investigations and discoveries on glacier dynamics and their influence on the world's climate. In the early 1950s, scientists and engineers from the US Army began drilling into polar ice caps for geological insight. These studies resulted in
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found trapped in the ice. In the past decade, polar ice caps have shown their most rapid decline in size with no true sign of recovery. Josefino Comiso, a senior research scientist at NASA, found that the "rate of warming in the Arctic over the last 20 years is eight times the rate of warming over
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has gained an average of 7,300 square miles (18,900 km) of sea ice per year. At the same time, the Arctic has been losing around 50 cubic kilometres (gigatons) of land ice per year, almost entirely from
Greenland's 2.6 million gigaton sheet. On 19 September 2014, for the first time since
224:. Portions of the ice that do not melt seasonally can get very thick, up to 3–4 meters thick over large areas, with ridges up to 20 meters thick. One-year ice is usually about 1 meter thick. The area covered by sea ice ranges between 9 and 12 million km. In addition, the
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data, when the sea ice covered 7.78 million square miles (20.14 million square kilometres). The 2014 five-day average maximum was reached on 22 Sep, when sea ice covered 7.76 million square miles (20.11 million square kilometres), according to
335:
drillings... and established the fundamental drilling technology for retrieving deep ice cores for climatologic archives." Polar ice caps have been used to track current climate patterns but also patterns over the past several thousands years from the traces of
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stayed above this benchmark extent for several days. The average maximum extent between 1981 and 2010 was 7.23 million square miles (18.72 million square kilometres). The single-day maximum extent in 2014 was reached on 20 Sep, according to
415:
Data collected in 2001 from NASA missions to Mars show that the southern residual ice cap undergoes sublimation inter-annually. The most widely accepted explanation is that fluctuations in the planet's orbit are causing the changes.
85:
There are no requirements with respect to size or composition for a body of ice to be termed a polar ice cap, nor any geological requirement for it to be over land, but only that it must be a body of solid phase matter in the
127:
variations of the ice caps takes place due to varied solar energy absorption as the planet or moon revolves around the Sun. Additionally, in geologic time scales, the ice caps may grow or shrink due to
173:
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covers about 1.71 million km and contains about 2.6 million km of ice. When the ice breaks off (calves) it forms icebergs scattered around the northern
Atlantic.
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Data from the
National Snow and Ice Data Center shows that the sea ice coverage of Antarctica has a slightly positive trend over the last three decades (1979–2009).
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also has polar ice caps. They consist of primarily water-ice with a few percent dust. Frozen carbon dioxide makes up a small permanent portion of the
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Over the past several decades, Earth's polar ice caps have gained significant attention because of the alarming decrease in land and sea ice.
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itself is applied more narrowly to bodies that are over land, and cover less than 50,000 km: larger bodies are referred to as
740:
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1979, Antarctic sea ice extent exceeded 7.72 million square miles (20 million square kilometres), according to the
269:. It covers an area of about 14.6 million km and contains between 25 and 30 million km of ice. Around 70% of the
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Grima, Cyril G.; Kofman, W.; Mouginot, J.; Phillips, R. J.; Herique, A.; Biccardi, D.; Seu, R.; Cutigni, M. (2009).
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Langway, Chester (April 2008). "The history of early polar ice cores, Cold
Regions Science and Technology".
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561:"State of the Cryosphere / Arctic and Antarctic Standardized Anomalies and Trends Jan 1979 – Jul 2009"
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has lost an average of 20,800 square miles (53,900 square kilometres) of sea ice per year while the
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The composition of the ice will vary. For example, Earth's polar caps are mainly water ice, whereas
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A photo describing the frozen methane and nitrogen on Pluto gathered from New
Horizons
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Polar ice caps form because high-latitude regions receive less energy in the form of
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27:
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missions had discovered a feature thought to be a polar ice cap on the dwarf planet
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90:. This causes the term "polar ice cap" to be something of a misnomer, as the term
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699:"Arctic Ice Shrinks 18% against Record, Sounding Climate Change Alarm Bells"
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High-latitude region of an astronomical body with major parts covered in ice
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331:"nearly forty years of research experience and achievements in deep polar
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This article is about polar ice caps in general. For Earth's ice cap, see
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Earth's polar caps have changed dramatically over the last 12,000 years.
792:"Mars Melt Hints at Solar, Not Human, Cause for Warming, Scientist Says"
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as a result of the previous melting of the ice sheet, by increasing the
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or the South Polar
Layered Deposits. In both hemispheres a seasonal
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855:"Pluto Is Larger Than Thought, Has Ice Cap, NASA Probe Reveals"
741:"North polar deposits of Mars: Extreme purity of the water ice"
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to confirm that the feature was in fact an ice cap composed of
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47:, with the entire north one visible, as imaged through the
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829:"New Horizons Probe Snaps Possible Polar Ice Cap On Pluto"
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79:
668:"Recent Warming of Arctic May Affect Worldwide Climate"
432:. The probe's flyby of Pluto in July 2015 allowed the
315:. This increase could be due to the reduction in the
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Extent of the Arctic sea-ice in
September 1978 – 2002
167:
Extent of the Arctic sea-ice in
February 1978 – 2002
563:. National Snow and Ice Data Center. Archived from
188:with the southern polar ice cap visible (courtesy
120:regions, resulting in lower surface temperatures.
645:"Polar ice is melting more faster than predicted"
380:'s north polar region with ice cap, composite of
896:
589:. NASA Goddard Space Flight Center. 8 April 2015
26:"Polar ice" redirects here. For the vodka, see
587:"Antarctic Sea Ice Reaches New Record Maximum"
497:The National Snow and Ice Data Center Glossary
197:
502:10 July 2009 at the Portuguese Web Archive
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273:on Earth is contained in this ice sheet.
253:A satellite composite image of Antarctica
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34:
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424:On 29 April 2015, NASA stated that its
288:reports that since the late 1970s, the
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696:
513:"NSIDC Arctic Sea Ice News Fall 2007"
790:Ravilious, Kate (28 February 2007).
665:
539:"Arctic Sea Ice News & Analysis"
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541:. National Snow and Ice Data Center
279:
105:'s polar ice caps are a mixture of
13:
725:National Snow and Ice Data Center
14:
926:
876:
697:Videl, John (19 September 2012).
408:frost deposits in the winter and
396:In addition to Earth, the planet
299:National Snow and Ice Data Center
233:National Snow and Ice Data Center
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647:. The Watchers. 10 March 2011
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745:Geophysical Research Letters
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802:National Geographic Society
515:. nsidc.org. Archived from
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198:North Polar ice cap melting
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727:A real hole near the pole
384:orbiter images (Courtesy
797:National Geographic News
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905:Geography of the Arctic
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212:is covered by floating
625:Cite journal requires
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361:Martian polar ice caps
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204:Arctic sea ice decline
142:Polar regions of Earth
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49:Hubble Space Telescope
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245:Climate of Antarctica
184:, Earth as seen from
38:
891:at Wikimedia Commons
827:Parnell, Brid-Aine.
765:10.1029/2008GL036326
440:imaging spectrometer
265:, is covered by the
107:solid carbon dioxide
853:Taylor Redd, Nola.
757:2009GeoRL..36.3203G
567:on 26 December 2012
412:during the spring.
267:Antarctic ice sheet
226:Greenland ice sheet
78:that is covered in
729:, 4 September 2012
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394:
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116:from the Sun than
52:
887:Media related to
666:Thompson, Elvia.
327:of the seawater.
231:According to the
76:natural satellite
28:Polar Ice (vodka)
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804:. Archived from
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775:. Archived from
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678:on 26 April 2021
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280:Historical cases
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359:Main articles:
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321:Antarctic Ocean
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181:The Blue Marble
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114:solar radiation
109:and water ice.
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21:Arctic ice pack
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864:10 September
862:. Retrieved
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806:the original
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704:The Guardian
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88:polar region
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72:dwarf planet
66:region of a
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437:ultraviolet
271:fresh water
261:land mass,
259:south polar
220:) over the
899:Categories
812:28 October
751:(3): n/a.
484:References
468:Cryosphere
410:sublimates
303:ice extent
263:Antarctica
243:See also:
239:South Pole
210:North Pole
202:See also:
118:equatorial
96:ice sheets
62:is a high-
859:Space.com
773:129096278
711:3 October
682:2 October
392:-Caltech)
294:Antarctic
186:Apollo 17
60:polar cap
910:Ice caps
707:. London
571:24 April
523:27 March
500:Archived
462:See also
448:nitrogen
382:Viking 1
333:ice core
317:salinity
257:Earth's
214:pack ice
208:Earth's
132:change.
125:Seasonal
64:latitude
753:Bibcode
473:Ice age
444:methane
319:of the
218:sea ice
130:climate
92:ice cap
838:20 May
833:Forbes
771:
651:18 May
593:10 May
450:ices.
367:, and
301:. The
290:Arctic
68:planet
769:S2CID
545:9 May
434:Alice
430:Pluto
420:Pluto
313:NSIDC
308:NSIDC
136:Earth
74:, or
866:2015
840:2015
814:2008
713:2012
684:2012
672:NASA
653:2015
631:help
595:2017
573:2010
547:2010
525:2008
446:and
398:Mars
386:NASA
378:Mars
355:Mars
343:and
286:NASA
190:NASA
103:Mars
45:Mars
39:The
761:doi
390:JPL
80:ice
58:or
43:on
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