Thinning can destabilize the shelf because the ice loses contact with points on the ocean floor that strongly influence its grounding or … A series of rifts that satellites have been monitoring since early 2019 grew rapidly last week. 18. Note: IceBridge flew a second mission to the Pine Island region on Wed., Oct. 26. Bamber, J. L., and Aspinall, W. P. (2013). West Antarctic Ice Sheet and CO2 Greenhouse effect – threat of disaster. Pine Island Glacier flows at rates of up to 4000 m per year2. It rapidly shrank back from around 16,400 years ago, when rising sea levels made this ice stream more buoyant, causing lift-off, decoupling from the ice sheet’s bed, and recession. However, outlet glaciers like Pine Island act as a brake on the flow of land-bound ice, which does raise sea levels as it empties into the sea. These numerical computer models indicate that annual rates of sea level rise from Pine Island Glacier could reach 2.7 cm per 100 years2. But as with other recent calvings at Pine Island and other West Antarctic glaciers, the primary driver was the influx of warm subsurface water into the Amundsen Sea Embayment, which is causing ice to melt from below. The grounding line receded by more than 20 km from 1996 to 20092. It remains difficult to assess how soon a collapse of Pine Island Glacier could occur, but a new paper by Bamber and Aspinall (2013) suggest that there is a growing view that the West Antarctic Ice Sheet could become unstable over the next 100 years16. The recent breakup, which was bigger than those in 2017 and 2018 but smaller than iceberg calvings in the early 2000s, according to Wouters, might have been partly driven by mild weather last winter. Scott, J.B.T., Gudmundsson, G.H., Smith, A.M., Bingham, R.G., Pritchard, H.D. Meltwater production underneath the ice shelf increased by 50% from 1994 to 2011; this increased melting results from stronger sub-ice-shelf circulation. 23. Free online lecture: The Glaciers are melting: What happens next? The white dots show how particles move with the ice which are initially randomly distributed over the ice surface. Jakobsson, M., Anderson, J.B., Nitsche, F.O., Dowdeswell, J.A., Gyllencreutz, R., Kirchner, N., Mohammed, R., O’Regan, M., Alley, R.B., Andandakrishnan, S., Eriksson, B., Kirshner, A., Fernandez, R., Stolldorf, T., Minzoni, R. & Majewski, W. Geological record of ice shelf break-up and grounding line retreat, Pine Island Bay, West Antarctica. Journal of Glaciology 27: 518-525. Nature 484, 502-505 (2012). Glaciol. These data suggest that the recession of this ice stream was largely controlled by sea level rise, with a 55 m in sea level rise during deglaciation resulting in 225 km of grounding-line recession26. If the glaciers were to pop loose at their grounding line, water could seep between ice and rock. Rignot, E., Bamber, J.L., van den Broeke, M.R., Davis, C., Li, Y., van de Berg, W.J. Rignot, E. Ice-shelf changes in Pine Island Bay, Antarctica, 1947-2000. The eastern half, including many smaller shards of ice, is following suit. It is remote from any research bases, so flying there means making multiple short flights, making fuel depots to allow scientists to hop to the location. Change 3, 424-427. You can use Google Earth below to explore the ice stream. Pine Island Glacier is one of the largest ice streams in Antarctica. 14. “The weak underbelly of the West Antarctic Ice Sheet”. Pine Island Glacier could collapse – stagnate and retreat far up into the bay, resulting in rapid sea level rise – within the next few centuries, raising global sea levels by 1.5 m11,12, out of a total of 3.3 m from the entire West Antarctic Ice Sheet13. The team observed the crack on the DC-8’s Oct. 14 flight. 12. The recession of the ice stream was also controlled by the presence or absence of ice shelves. 20. Jenkins, A., Dutrieux, P., Jacobs, S.S., McPhail, S.D., Perrett, J.R., Webb, A.T. & White, D. Observations beneath Pine Island Glacier in West Antarctica and implications for its retreat. The ice stream is steepening, which increases the gravitational driving stress, helping it to flow faster, and there is no indication that the glacier is approaching a steady state10. Pine Island Glacier ice shelf periodically calves huge icebergs. Over the weekend, the European Space Agencyâs Sentinel satellites spotted a significant breakup, or calving event, underway on Pine Island Glacierâs floating ice shelf. Sea ice keeps ships away, making it difficult to access the ice stream from the ocean. Science (2011). Photograph courtesy Copernicus Sentinel, European Space Agency, A huge iceberg just broke off West Antarcticaâs most endangered glacier, https://www.nationalgeographic.com/science/2020/02/antarctica-pine-island-glacier.html, Find out why it's our fault that West Antarctica is melting. It seems that the glacier is capable of very rapid recession within millennial timescales27, and that the dynamics between ice shelf and ice stream are intrinsically linked. Bamber, J.L., Riva, R.E.M., Vermeersen, B.L.A. If the ice isn’t in fact that surprisingly low density, I would suggest you correct that. Uncertainty over the future behaviour of Pine Island Glacier in West Antarctica is one of the largest constraints on accurately predicting future sea level rise16. Pine Island Glacier (PIG) in West Antarctica drains out to the Amundsen Sea through Pine Island Glacier Ice Shelf (PIGIS). These typically occurred when a rift at the heavily fractured shear margin propagated across the width of the ice shelf. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, 1637-1655 (2006). Some studies have suggested that the entire main trunk of Pine Island Glacier could unground and become afloat within 100 years14, but more recent modelling efforts suggest that much longer timescales are needed to unground the entire trunk2. The Antarctic ice sheetis the largest mass of ice on earth, containing a volume of water equivalent to 57 m (187 ft) of global sea level. Pine Island Glacier is buttressed by a large, floating ice shelf, which helps to stabilise the glacier, but this ice shelf is itself thinning and recently calved a huge iceberg. Pine Island is Antarcticaâs most vulnerable. If you examine the MODIS imagery are you sure about the July 2013 calving date, no separation occurred until November 2013? A rift in Pine Island Glacier ice shelf in West Antarctica, photographed on November 4th, 2016. Digital Story Innovation Team. The recently calved iceberg may be 720 km2, but that’s the least of this ice stream’s worries. dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice. Gladstone, R.M., Lee, V., Rougier, J., Payne, A.J., Hellmer, H., Le Brocq, A., Shepherd, A., Edwards, T.L., Gregory, J. And that gateway is shattering before our eyes. Annals of Glaciology 34, 277-282 (2002). The latest calving event is the seventh of the past century for Pine Island, with prior calvings occurring in 2001, 2007, 2013, 2015, 2017, and 2018, according to Copernicus. However, scientists have several ingenious ways in which they can observe changes to this fragile, important ice stream. The velocity is well above that required to maintain mass balance – so the ice stretches longitudinally, and thins vertically3. This threshold has yet to be passed. 26. Earth and Planetary Science Letters 333–334, 191-199 (2012). It is a normal part of life for the floating ice from huge glaciers to fracture near the seaward edge and … In the lead-up to its recent calving, the glacier was moving even more rapidly than usual. A crack runs across the floating ice shelf of Pine Island Glacier in Antarctica, seen from NASA’s DC-8 on Oct. 14, 2011. Credit: Michael Studinger/NASA. âThe events of the past five to 10 years seem to be exceptional for the area compared to the retreat in the past 70 years,â Bert Wouters, a satellite remote sensing expert at TU Delft in the Netherlands who has been monitoring Pine Island Glacier closely, writes in an email. The shear zone is located where the glacier meets the ice shelf, which acts as a braking system that slows the downstream flow of the glaciers towards the sea. It periodically, every 10 or so years, calves large icebergs – but on their own, they are not worrisome. Since 2012, the glacier has been shedding 58 billion tons of ice a year, making the biggest single contribution to global sea level rise of any ice stream on the planet. 2. hence that the ice is breaking of because of water pressure from below. The ice shelf around Pine Island Glacier is currently thinning, and it is warmed from below by Circumpolar Deep Water that flows onto the continental shelf22,23. The latest returns from the MODIS instrument on NASAâs Terra satellite suggest the western portion of the recently calved ice, including the largest iceberg, has rapidly rotated out into Pine Island Bay, according to NASA glaciologist Christopher Shuman. The point at which glaciers and ice shelves start to float is the … Note article at Realclimate. 16. It quickly shattered into a constellation of smaller icebergs, the largest of which was big enough to earn itself a name: B-49. Learn how your comment data is processed. Post-LGM deglaciation in Pine Island Bay, West Antarctica. Finally, scientists on board ships have deployed ‘Autosub’ beneath the very ice shelf, to make observations where no man can go. The study results reveal that since 2016, damage in the shear zone of Pine Island and Thwaites glaciers has rapidly developed. From ice-shelf tributary to tidewater glacier: continued rapid glacier recession, acceleration and thinning of Röhss Glacier following the 1995 collapse of the Prince Gustav Ice Shelf on the Antarctic Peninsula. Can you identify the ice shelf? It reached its current position around 10,000 years ago27. & Padman, L. Antarctic ice-sheet loss driven by basal melting of ice shelves. Hughes, T. A simple holistic hypothesis for the self-destruction of ice sheets. On the ice-covered edge of a remote West Antarctic bay, the continentâs most imperiled glaciers threaten to redraw Earthâs coastlines. Glasser, N.F., Scambos, T.A., Bohlander, J.A., Truffer, M., Pettit, E.C. Ocean-excited plate waves in the Ross and Pine Island Glacier ice shelves - Volume 64 Issue 247 - ZHAO CHEN, PETER D. BROMIRSKI, PETER GERSTOFT, RALPH A. STEPHEN, DOUGLAS A. WIENS, RICHARD C. ASTER, ANDREW A. Mercer, J.H. http://www.realclimate.org/index.php/archives/2009/11/is-pine-island-glacier-the-weak-underbelly-of-the-west-antarctic-ice-sheet/. Much of this ice loss is from Pine Island Glacier, which has thinned since at least 1992, driven by changes in ocean heat transport beneath its ice shelf and retreat of the grounding line. Are these on-going changes unprecedented, or are they part of the normal behaviour for the glacier? Pine Island Glacier is one of the most dynamic features of the Antarctic Ice Sheet. By Youtube user pikff1. Pritchard, H.D., Ligtenberg, S.R.M., Fricker, H.A., Vaughan, D.G., van den Broeke, M.R. The intervals between the events seem to be getting shorter, another symptom of the glacierâs unhealthy state. 13. Cryosphere 3, 125-131 (2009). Quaternary Science Reviews 38, 11-26 (2012). This type of calving is common on polar ice shelves, with no clear connection to ocean‐ice dynamic forcing. 53 , 156 – 162 ( 2012 ). & Scheuchl, B. Pine Island Glacier has undergone several major iceberg calving events over the past decades. & Anderson, J.B. Reconstruction of the West Antarctic ice sheet in Pine Island Bay during the Last Glacial Maximum and its subsequent retreat history. It is out of balance. West Antarctic Ice Sheet collapse – the fall and rise of a paradigm. âAll in all, not good news for the inland ice flowing out from Pine Island Glacier,â Shuman says. This ice shelf collapsed after 10600 years ago28, when warmer waters flowed onto the continental shelf. All rights reserved. The area … … As Pine Islandâs ice shelf weakens, so does this buttressing force, which can hasten the flow of ice from the land. The Pine Island Glacier is one of the fastest ice streams in West Antarctica. The ice shelf currently loses around 62.3 ± 5 Gigatonnes per year of ice through calving, and loses 101.2 ± 8 Gigatonnes per year through basal melting24. Quaternary Science Reviews 30, 1829-1845 (2011). On Friday I had the opportunity to be co-pilot for the British Antarctic Survey Twin Otter airplane flight taking 2000 lbs of freight down to Pine Island Glacier … Shrinking Antarctic ice shelf Pine Island Glacier sheds giant iceberg. Jacobs, S.S., Jenkins, A., Giulivi, C.F. De Angelis, H. & Skvarca, P. Glacier surge after ice shelf collapse. 2008, you can see that mass losses from Pine Island Glacier and Thwaites Glacier dominate Antarctic Ice Sheet ice losses. Pine Island Glacier and its neighbor Thwaites Glacier are the gateway to a massive cache of frozen water, one that would raise global sea levels by four feet if it were all to spill into the sea. | Pine Island Glacier ice shelf | Pine Island Glacier: the longer term view | Conclusions | References | Comments |. & Corr, H.F.J. Updated February 13, 2020 17:43:14 It is buttressed by a large ice shelf that is currently thinning8, and the ice stream itself has a negative mass balance (the melting is not replaced by snowfall)3, it is flowing faster9, and the grounding line is retreating further and further up into the bay. This site uses Akismet to reduce spam. 22. Itâs also in line with the bigger picture of climate change. Glaciers that end in the ocean like this are called Tidewater Glaciers.They may be grounded (the glacier is in contact with the bed entirely), or parts of the glacier terminus may be floating. The area drained by Pine Island Glacier comprises about 10% of the West Antarctic Ice Sheet. In 2015, an iceberg measuring almost 225 square miles (580 square kilometers) broke off from the Pine Island Glacier, which forms part of the ice shelf that bounds the West Antarctic Ice Sheet. However, this iceberg calving event is a natural process, part of how the ice shelf regularly calves – this ice shelf spawns huge icebergs every 6-10 years. 4. Inland thinning of Pine Island Glacier, West Antarctica. It’s a dangerous business; several iterations of Autosub have been lost under the ice. Nature 271, 321-325 (1978). 24. Pine Island Glacier, along with neighboring Thwaites Glacier, is one of the main pathways for ice entering the Amundsen Sea from the West Antarctic Ice Sheet.Pine Island is also one the fastest-retreating glaciers in Antarctica. Climatic Change 91, 65-79 (2008). Ann. Pine Island Glacier is one of the largest ice streams in Antarctica, and drains much of the West Antarctic Ice Sheet. Rignot, E., Mouginot, J. Abstract. What is the global volume of land ice and how is it changing? Pine Island Glacier (PIG) Research Team: Robert Bindschadler (NASA Emeritus) A series of instruments, including a small, tube-shaped robot called Icefin, were deployed to collect data and capture the very first footage of this mysterious realm. Look for more imagery of the crack coming soon. As the ice shelf thins, more water is able to circulate beneath it22, exacerbating the problem and encouraging further melting. (2012) predict recession over the next 200 years with huge uncertainty over the rate of retreat, and full collapse of the trunk of Pine Island Glacier during the 22nd Century remains a possibility15. Despite this interest, Pine Island Glacier is difficult to access. Over the past 40 years Pine Island and Thwaites Glacier have contributed ~5 mm to global sea level rise. NASA image acquired October 24, 2011 NASA's DC-8 flew over the Pine Island Glacier Ice Shelf on Oct. 14, 2011 as part of the agency's Operation IceBridge. Kirshner, A.E., Anderson, J.B., Jakobsson, M., O’Regan, M., Majewski, W. & Nitsche, F.O. Lowe, A.L. 15. Ice Shelf Melting Around Antarctica. http://glacierchange.wordpress.com/2013/11/13/pine-island-glacier-2013-iceberg-rift-update/ It suggests: A collapse of Pine Island Glacier could occur within 1000-2000 years, raising sea levels by up to 1.5 m, but it is unlikely to contribute to more than 2.7 cm of sea level rise over the next 100 years. Pine Island Glacier drains much of the marine-based West Antarctic Ice Sheet, and it has a configuration susceptible to rapid disintegration and recession. Shuman says that the breakup of Pine Islandâs latest iceberg into many small shards âsuggests just how âweakâ the floating ice tongue of [Pine Island] has become.â That, combined with the ice frontâs current, seemingly unstable configuration, suggests that there will be more disintegration soon. Go to top or jump to Marine Ice Sheet Instability. This image, taken on February 11 by the Copernicus Sentinel-2 mission, shows the Pine Island Glacier's newly calved icebergs in detail. It flows, together with Thwaites Ice Stream, into the Amundsen Sea embayment in West Antarctica, and the two ice streams together drain ~5% of the Antarctic Ice Sheet1. Science 291, 862-864 (2001). It can dive to 1600 m and travel 400 km, and it has a clever collision avoidance system. Around this time, Pine Island Glacier started to shed smaller icebergs more frequently. The DC-8 took off on Oct. 26, 2011, to collect more data on the ice shelf and the crack. Earth and Planetary Science Letters 280, 51-60 (2009). However, when retreating further, they could destabilize the entire West Antarctic Ice Sheet, which contains enough ice to … Your email address will not be published. Scientists think the change in calving frequency is likely related to the thinning of the ice shelf. The ice then moves under its own weight toward the edges of the continent. What is the ice volume of Thwaites Glacier? 25. The image was taken during the NASA/Centro de Estudios Cientificos, Chile (CECS) Antarctic campaign of Fall 2002. For Pine Island, itâs the latest in a string of dramatic calving events that scientists fear may be the prelude to an even larger disintegration as climate change thaws the frozen continent. & Le Brocq, A.M. Reassessment of the potential sea-level rise from a collapse of the West Antarctic Ice Sheet. The ice shelf base of across-profiles III and IV does not change much in depth but the basal channel itself widens. Journal of Geophysical Research-Earth Surface 112(2007).
Floor Function Symbol, Weather Tehran 14 Days, Web Analytics For E-commerce, What I Eat In A Day Marathon Training, California Pizza Kitchen Annapolis Menu, Buy Kate Somerville, Horizontal Logo Design, Packet Capture Windows,