East Antarctic Ice Sheet

80°S 60°E / 80°S 60°E / -80; 60

East Antarctic ice sheet
TypeIce sheet
Thickness~2.2 km (1.4 mi) (average),[1] ~4.9 km (3.0 mi) (maximum) [2]

The East Antarctic Ice Sheet (EAIS) lies between 45° west and 168° east longitudinally. It was first formed around 34 million years ago,[3] and it is the largest ice sheet on the entire planet, with far greater volume than the Greenland ice sheet or the West Antarctic Ice Sheet (WAIS), from which it is separated by the Transantarctic Mountains. The ice sheet is around 2.2 km (1.4 mi) thick on average and is 4,897 m (16,066 ft) at its thickest point.[2] It is also home to the geographic South Pole, South Magnetic Pole and the Amundsen–Scott South Pole Station.

The surface of the EAIS is the driest, windiest, and coldest place on Earth. Lack of moisture in the air, high albedo from the snow as well as the surface's consistently high elevation[4] results in the reported cold temperature records of nearly −100 °C (−148 °F).[5][6] It is the only place on Earth cold enough for atmospheric temperature inversion to occur consistently. That is, while the atmosphere is typically warmest near the surface and becomes cooler at greater elevation, atmosphere during the Antarctic winter is cooler at the surface than in its middle layers. Consequently, greenhouse gases actually trap heat in the middle atmosphere and reduce its flow towards the surface while the temperature inversion lasts.[4]

Due to these factors, East Antarctica had experienced slight cooling for decades while the rest of the world warmed as the result of climate change. Clear warming over East Antarctica only started to occur since the year 2000, and was not conclusively detected until the 2020s.[7][8] In the early 2000s, cooling over East Antarctica seemingly outweighing warming over the rest of the continent was frequently misinterpreted by the media and occasionally used as an argument for climate change denial.[9][10][11] After 2009, improvements in Antarctica's instrumental temperature record have proven that the warming over West Antarctica resulted in consistent net warming across the continent since the 1957.[12]

Because the East Antarctic ice sheet has barely warmed, it is still gaining ice on average.[13][14] for instance, GRACE satellite data indicated East Antarctica mass gain of 60 ± 13 billion tons per year between 2002 and 2010.[15] It is most likely to first see sustained losses of ice at its most vulnerable locations such as Totten Glacier and Wilkes Basin. Those areas are sometimes collectively described as East Antarctica's subglacial basins, and it is believed that once the warming reaches around 3 °C (5.4 °F), then they would start to collapse over a period of around 2,000 years,[16][17] This collapse would ultimately add between 1.4 m (4 ft 7 in) and 6.4 m (21 ft 0 in) to sea levels, depending on the ice sheet model used.[18] The EAIS as a whole holds enough ice to raise global sea levels by 53.3 m (175 ft).[2] However, it would take global warming in a range between 5 °C (9.0 °F) and 10 °C (18 °F), and a minimum of 10,000 years for the entire ice sheet to be lost.[16][17]

  1. ^ Cite error: The named reference Torsvik2008 was invoked but never defined (see the help page).
  2. ^ a b c Fretwell, P.; Pritchard, H. D.; Vaughan, D. G.; Bamber, J. L.; Barrand, N. E.; Bell, R.; Bianchi, C.; Bingham, R. G.; Blankenship, D. D. (2013-02-28). "Bedmap2: improved ice bed, surface and thickness datasets for Antarctica". The Cryosphere. 7 (1): 375–393. Bibcode:2013TCry....7..375F. doi:10.5194/tc-7-375-2013. hdl:1808/18763. ISSN 1994-0424.
  3. ^ Cite error: The named reference Galeotti2016 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Singh2020 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Scambos2018 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference VizcarraNSIDC2018 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Xin2023a was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Xin2023b was invoked but never defined (see the help page).
  9. ^ Davidson, Keay (2002-02-04). "Media goofed on Antarctic data / Global warming interpretation irks scientists". San Francisco Chronicle. Retrieved 2013-04-13.
  10. ^ Eric Steig; Gavin Schmidt (2004-12-03). "Antarctic cooling, global warming?". Real Climate. Retrieved 2008-08-14. At first glance this seems to contradict the idea of "global" warming, but one needs to be careful before jumping to this conclusion. A rise in the global mean temperature does not imply universal warming. Dynamical effects (changes in the winds and ocean circulation) can have just as large an impact, locally as the radiative forcing from greenhouse gases. The temperature change in any particular region will in fact be a combination of radiation-related changes (through greenhouse gases, aerosols, ozone and the like) and dynamical effects. Since the winds tend to only move heat from one place to another, their impact will tend to cancel out in the global mean.
  11. ^ Peter Doran (2006-07-27). "Cold, Hard Facts". The New York Times. Archived from the original on April 11, 2009. Retrieved 2008-08-14.
  12. ^ Steig, E. J.; Schneider, D. P.; Rutherford, S. D.; Mann, M. E.; Comiso, J. C.; Shindell, D. T. (2009). "Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year". Nature. 457 (7228): 459–462. Bibcode:2009Natur.457..459S. doi:10.1038/nature07669. PMID 19158794. S2CID 4410477.
  13. ^ Zwally, H. Jay; Robbins, John W.; Luthcke, Scott B.; Loomis, Bryant D.; Rémy, Frédérique (29 March 2021). "Mass balance of the Antarctic ice sheet 1992–2016: reconciling results from GRACE gravimetry with ICESat, ERS1/2 and Envisat altimetry". Journal of Glaciology. 67 (263): 533–559. doi:10.1017/jog.2021.8. Although their methods of interpolation or extrapolation for areas with unobserved output velocities have an insufficient description for the evaluation of associated errors, such errors in previous results (Rignot and others, 2008) caused large overestimates of the mass losses as detailed in Zwally and Giovinetto (Zwally and Giovinetto, 2011).
  14. ^ NASA (7 July 2023). "Antarctic Ice Mass Loss 2002–2023".
  15. ^ King, M. A.; Bingham, R. J.; Moore, P.; Whitehouse, P. L.; Bentley, M. J.; Milne, G. A. (2012). "Lower satellite-gravimetry estimates of Antarctic sea-level contribution". Nature. 491 (7425): 586–589. Bibcode:2012Natur.491..586K. doi:10.1038/nature11621. PMID 23086145. S2CID 4414976.
  16. ^ a b Cite error: The named reference ArmstrongMcKay2022 was invoked but never defined (see the help page).
  17. ^ a b Cite error: The named reference ArmstrongMcKayExplainer was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Pan2021 was invoked but never defined (see the help page).