Journal ArticleDOI
Antarctic ice-sheet loss driven by basal melting of ice shelves
Hamish D. Pritchard,Stefan R. M. Ligtenberg,Helen A. Fricker,David G. Vaughan,M. R. van den Broeke,Laurie Padman +5 more
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TLDR
Satellite laser altimetry and modelling of the surface firn layer are used to reveal the circum-Antarctic pattern of ice-shelf thinning through increased basal melt, which implies that climate forcing through changing winds influences Antarctic ice-sheet mass balance, and hence global sea level, on annual to decadal timescales.Abstract:
Using satellite laser altimetry, basal melting of ice shelves is determined to be the main driver of Antarctic ice-sheet loss,with changing climate the likely cause. Ice shelves — those parts of the ice sheets that extend over the ocean — are known to provide a buttressing effect that limits the velocity of upstream glaciers and ice streams. In Antarctica, loss of ice shelves has already been implicated in the accelerated motion of some ice masses, but the extent of ice-shelf wasting remained unknown. Now, Pritchard et al. present a complete survey of Antarctic ice-shelf thinning between 2003 and 2008, and reveal loss rates of up to 7 metres per year. Much of the thinning is attributable to wind-driven movement of warm water through deep troughs crossing the continental shelf. The authors conclude that the thinning has led to loss of buttressing strength and accelerated loss of ice mass. Accurate prediction of global sea-level rise requires that we understand the cause of recent, widespread and intensifying1,2 glacier acceleration along Antarctic ice-sheet coastal margins3. Atmospheric and oceanic forcing have the potential to reduce the thickness and extent of floating ice shelves, potentially limiting their ability to buttress the flow of grounded tributary glaciers4. Indeed, recent ice-shelf collapse led to retreat and acceleration of several glaciers on the Antarctic Peninsula5. But the extent and magnitude of ice-shelf thickness change, the underlying causes of such change, and its link to glacier flow rate are so poorly understood that its future impact on the ice sheets cannot yet be predicted3. Here we use satellite laser altimetry and modelling of the surface firn layer to reveal the circum-Antarctic pattern of ice-shelf thinning through increased basal melt. We deduce that this increased melt is the primary control of Antarctic ice-sheet loss, through a reduction in buttressing of the adjacent ice sheet leading to accelerated glacier flow2. The highest thinning rates occur where warm water at depth can access thick ice shelves via submarine troughs crossing the continental shelf. Wind forcing could explain the dominant patterns of both basal melting and the surface melting and collapse of Antarctic ice shelves, through ocean upwelling in the Amundsen6 and Bellingshausen7 seas, and atmospheric warming on the Antarctic Peninsula8. This implies that climate forcing through changing winds influences Antarctic ice-sheet mass balance, and hence global sea level, on annual to decadal timescales.read more
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Journal ArticleDOI
Bedmap2: improved ice bed, surface and thickness datasets for Antarctica
Peter T. Fretwell,Hamish D. Pritchard,David G. Vaughan,Jonathan L. Bamber,Nicholas E. Barrand,Ruth Bell,Cesidio Bianchi,Robert Bingham,Donald D. Blankenship,Gino Casassa,Ginny A. Catania,Denis Callens,Howard Conway,Alison J. Cook,Hugh F. J. Corr,Detlef Damaske,Volkmar Damm,Fausto Ferraccioli,René Forsberg,Shuji Fujita,Y. Gim,Prasad Gogineni,J. A. Griggs,Richard C. A. Hindmarsh,Per Holmlund,John W. Holt,Robert W. Jacobel,Adrian Jenkins,Wilfried Jokat,Tom A. Jordan,Edward C. King,Jack Kohler,William B. Krabill,M. Riger-Kusk,Kirsty Langley,German Leitchenkov,Carl Leuschen,Bruce P. Luyendyk,Kenichi Matsuoka,Jeremie Mouginot,F. O. Nitsche,Yoshifumi Nogi,Ole Anders Nøst,S. V. Popov,Eric Rignot,David M. Rippin,Andrés Rivera,Jason L. Roberts,Neil Ross,Martin J. Siegert,Andrew Smith,Daniel Steinhage,Michael Studinger,Bo Sun,B. K. Tinto,Brian C. Welch,Douglas S. Wilson,Duncan A. Young,Cui Xiangbin,Achille Zirizzotti +59 more
TL;DR: Bedmap2 as discussed by the authors is a suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60° S. In particular, the Bedmap2 ice thickness grid is made from 25 million measurements, over two orders of magnitude more than were used in Bedmap1.
Journal ArticleDOI
Contribution of Antarctica to past and future sea-level rise
Robert M. DeConto,David Pollard +1 more
TL;DR: A model coupling ice sheet and climate dynamics—including previously underappreciated processes linking atmospheric warming with hydrofracturing of buttressing ice shelves and structural collapse of marine-terminating ice cliffs—is calibrated against Pliocene and Last Interglacial sea-level estimates and applied to future greenhouse gas emission scenarios.
Journal ArticleDOI
A reconciled estimate of ice-sheet mass balance
Andrew Shepherd,Erik R. Ivins,Geruo A,Valentina R. Barletta,Michael J. Bentley,Srinivas Bettadpur,Kate Briggs,David H. Bromwich,René Forsberg,Natalia Galin,Martin Horwath,S. S. Jacobs,Ian Joughin,Matt A. King,Matt A. King,Jan T. M. Lenaerts,Jilu Li,Stefan R. M. Ligtenberg,Adrian Luckman,Scott B. Luthcke,Malcolm McMillan,Rakia Meister,Glenn A. Milne,Jeremie Mouginot,Alan Muir,Julien P. Nicolas,John Paden,Antony J. Payne,Hamish D. Pritchard,Eric Rignot,Eric Rignot,Helmut Rott,Louise Sandberg Sørensen,Ted Scambos,Bernd Scheuchl,Ernst Schrama,Ben Smith,Aud Venke Sundal,Jan H. van Angelen,Willem Jan van de Berg,Michiel R. van den Broeke,David G. Vaughan,Isabella Velicogna,Isabella Velicogna,John Wahr,Pippa L. Whitehouse,Duncan J. Wingham,Donghui Yi,Duncan A. Young,H. Jay Zwally +49 more
TL;DR: There is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty, and the mass balance of Earth’s polar ice sheets is estimated by combining the results of existing independent techniques.
Supplementary Materials for A Reconciled Estimate of Ice-Sheet Mass Balance
Andrew Shepherd,Erik R. Ivins,Geruo A,Valentina R. Barletta,Michael J. Bentley,Srinivas Bettadpur,Kate Briggs,David H. Bromwich,René Forsberg,Natalia Galin,Martin Horwath,Stan Jacobs,Ian Joughin,Matt A. King,Jan T. M. Lenaerts,Jilu Li,Stefan R. M. Ligtenberg,Adrian Luckman,Scott B. Luthcke,Malcolm McMillan,Glenn A. Milne,Jeremie Mouginot,Alan Muir,Julien Nicolas,John Paden,A. J. Payne,Hamish D. Pritchard,Eric Rignot,Helmut Rott,Ted Scambos,Bernd Scheuchl,Ernst Schrama,Ben Smith,Jan H. van Angelen,Willem Jan van de Berg,Michiel van den Broeke,Isabella Velicogna,John Wahr,Pippa L. Whitehouse,Duncan J. Wingham,Donghui Yi,Duncan Young,H. Jay Zwally +42 more
Journal ArticleDOI
A Reconciled Estimate of Glacier Contributions to Sea Level Rise: 2003 to 2009
Alex S. Gardner,Alex S. Gardner,Geir Moholdt,J. Graham Cogley,Bert Wouters,Bert Wouters,Anthony Arendt,John Wahr,John Wahr,Etienne Berthier,Regine Hock,Regine Hock,W. Tad Pfeffer,Georg Kaser,Stefan R. M. Ligtenberg,Tobias Bolch,Tobias Bolch,Martin Sharp,Jon Ove Hagen,Michiel R. van den Broeke,Frank Paul +20 more
TL;DR: It is found that glaciers in the Arctic, Canada, Alaska, coastal Greenland, the southern Andes, and high-mountain Asia contribute approximately as much melt water as the ice sheets themselves: 260 billion tons per year between 2003 and 2009, accounting for about 30% of the observed sea-level rise during that period.
References
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Journal ArticleDOI
Ice sheet grounding line dynamics: Steady states, stability, and hysteresis
TL;DR: In this paper, the results of boundary layer theory for ice flux in the transition zone against numerical solutions that are able to resolve the transition zones were verified. But the results were not applied to the large-scale dynamics of a marine ice sheet.
Journal ArticleDOI
Recent Antarctic ice mass loss from radar interferometry and regional climate modelling
Eric Rignot,Eric Rignot,Eric Rignot,Jonathan L. Bamber,Michiel R. van den Broeke,Curt H. Davis,Yonghong Li,Willem Jan van de Berg,Erik van Meijgaard +8 more
TL;DR: In this article, the authors estimate that East Antarctica is close to a balanced mass budget, but large losses of ice occur in the narrow outlet channels of West Antarctic glaciers and at the northern tip of the Antarctic peninsula.
Journal ArticleDOI
Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets
TL;DR: In this paper, a high-resolution ICESat (Ice, Cloud and land Elevation Satellite) laser altimetry is used to map changes along these ocean margins; the results show that dynamic thinning is more important and extensive than previously thought.
Journal ArticleDOI
Global Trends in Wind Speed and Wave Height
TL;DR: In this article, the authors used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period.
Global trends in wind speed and wave height over the past 25 years
TL;DR: A 23-year database of calibrated and validated satellite altimeter measurements is used to investigate global changes in oceanic wind speed and wave height over this period and finds a general global trend of increasing values of windspeed and, to a lesser degree, wave height.
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Bedmap2: improved ice bed, surface and thickness datasets for Antarctica
Peter T. Fretwell,Hamish D. Pritchard,David G. Vaughan,Jonathan L. Bamber,Nicholas E. Barrand,Ruth Bell,Cesidio Bianchi,Robert Bingham,Donald D. Blankenship,Gino Casassa,Ginny A. Catania,Denis Callens,Howard Conway,Alison J. Cook,Hugh F. J. Corr,Detlef Damaske,Volkmar Damm,Fausto Ferraccioli,René Forsberg,Shuji Fujita,Y. Gim,Prasad Gogineni,J. A. Griggs,Richard C. A. Hindmarsh,Per Holmlund,John W. Holt,Robert W. Jacobel,Adrian Jenkins,Wilfried Jokat,Tom A. Jordan,Edward C. King,Jack Kohler,William B. Krabill,M. Riger-Kusk,Kirsty Langley,German Leitchenkov,Carl Leuschen,Bruce P. Luyendyk,Kenichi Matsuoka,Jeremie Mouginot,F. O. Nitsche,Yoshifumi Nogi,Ole Anders Nøst,S. V. Popov,Eric Rignot,David M. Rippin,Andrés Rivera,Jason L. Roberts,Neil Ross,Martin J. Siegert,Andrew Smith,Daniel Steinhage,Michael Studinger,Bo Sun,B. K. Tinto,Brian C. Welch,Douglas S. Wilson,Duncan A. Young,Cui Xiangbin,Achille Zirizzotti +59 more
A reconciled estimate of ice-sheet mass balance
Andrew Shepherd,Erik R. Ivins,Geruo A,Valentina R. Barletta,Michael J. Bentley,Srinivas Bettadpur,Kate Briggs,David H. Bromwich,René Forsberg,Natalia Galin,Martin Horwath,S. S. Jacobs,Ian Joughin,Matt A. King,Matt A. King,Jan T. M. Lenaerts,Jilu Li,Stefan R. M. Ligtenberg,Adrian Luckman,Scott B. Luthcke,Malcolm McMillan,Rakia Meister,Glenn A. Milne,Jeremie Mouginot,Alan Muir,Julien P. Nicolas,John Paden,Antony J. Payne,Hamish D. Pritchard,Eric Rignot,Eric Rignot,Helmut Rott,Louise Sandberg Sørensen,Ted Scambos,Bernd Scheuchl,Ernst Schrama,Ben Smith,Aud Venke Sundal,Jan H. van Angelen,Willem Jan van de Berg,Michiel R. van den Broeke,David G. Vaughan,Isabella Velicogna,Isabella Velicogna,John Wahr,Pippa L. Whitehouse,Duncan J. Wingham,Donghui Yi,Duncan A. Young,H. Jay Zwally +49 more