Present and Future Stability of Larsen C Ice Shelf (SOLIS)
Lead Research Organisation:
Swansea University
Department Name: School of the Environment and Society
Abstract
The widely publicised rapid disintegrations of the Larsen A and B ice shelves on the Antarctic Peninsula in 1995 and 2002 were extraordinary demonstrations of the dramatic impact that climatic changes can have on this region. Ice shelf break-up is of particular scientific and public concern for two main reasons: [a] Ice shelves are sustained principally by inflow of ice from glaciers and ice streams (confined, fast-flowing 'conveyor belts' that transport ice from the interior of ice sheets to their margins). As the buttressing force is removed as a result of ice shelf collapse, these glaciers and ice streams can speed up and thus increase discharge from the ice sheet interior to the ocean. This could potentially lead to rapid and sustained shrinkage of these ice sheets and an equally dramatic increase in sea level. [b] In addition to accelerated input of cold melt water as a result of [a], ice shelf disintegration may also lead to modification of regional patterns of ocean circulation and the formation of Antarctic Bottom Water (AABW). AABW is an important contributor to the global ocean circulation which in turn regulates world-wide climate. If modification of AABW formation can trigger changes in this circulation, ice shelf collapse could indirectly contribute to alterations of world-wide climate patterns. If rates of climatic warming on the Antarctic Peninsula continue to be anomalously high (presently ~ 4 degrees C per century), the stability of the remaining ice shelves in this region comes into question. Larsen C, as the largest ice shelf on the Antarctic Peninsula and the southern neighbour of Larsen B which collapsed in 2002, has thinned progressively over the past 15 years. This could indicate that the Larsen C ice shelf has already entered a process of retreat or possibly collapse. If the ice shelf were to disintegrate (even partially), it is likely that more shelf ice would be lost in this single incident than has been lost by all previous incidents on the Antarctic Peninsula taken together. The key question is therefore: Is the Larsen C ice shelf likely to collapse in the future? The proposed project aims to answer that question. The stability of an ice shelf is controlled by a range of ice-internal controls, including [a] ice composition and structure; [b] the balance between stress intensity (acting as a de-stabilising force) and ice fracture toughness (the ability of ice to resist stress, thus acting as a stabilising force); and [c] patterns and processes of rifting. Climatic changes can force the internal controls not only directly but also indirectly via a range of external controls (mass balance and thus total ice shelf thickness; ice shelf geometry; oceanographic and sea ice processes; meteorology). In characterising the internal controls and modelling direct and indirect (via the external controls) forcing by climatic conditions, we propose to adopt a three-tier strategy: [a] field-based investigations using standard geophysical methods as the core activity of the project providing the required ground control; [b] upscaling of the field data to the whole ice shelf using established remote sensing techniques; and [c] forcing of an adapted computer model (previously applied successfully to the Filchner-Ronne and Larsen B ice shelves) using the upscaled data. The model outputs will allow [a] identification of how stable the Larsen C ice shelf is at present; [b] simulation of a range of future scenarios including rapid ice shelf retreat or disintegration; and [c] identification of the most realistic future scenario. This will enable us to conclude whether the Larsen C ice shelf is likely to collapse in the future.
Organisations
Publications
Brisbourne A
(2020)
An updated seabed bathymetry beneath Larsen C Ice Shelf, Antarctic Peninsula
in Earth System Science Data
Brisbourne A
(2019)
An updated seabed bathymetry beneath Larsen C Ice Shelf, west Antarctic
Chester M
(2017)
Systems Analysis of complex glaciological processes and application to calving of Amery Ice Shelf, East Antarctica
in Annals of Glaciology
Glasser N
(2017)
Surface structure and stability of the Larsen C ice shelf, Antarctic Peninsula
in Journal of Glaciology
Jansen D
(2017)
Present stability of the Larsen C ice shelf, Antarctic Peninsula
in Journal of Glaciology
Jansen D
(2015)
Brief Communication: Newly developing rift in Larsen C Ice Shelf presents significant risk to stability
in The Cryosphere
Jansen D
(2013)
Marine ice formation in a suture zone on the Larsen C Ice Shelf and its influence on ice shelf dynamics
in Journal of Geophysical Research: Earth Surface
King M
(2011)
Ocean tides in the Weddell Sea: New observations on the Filchner-Ronne and Larsen C ice shelves and model validation
in Journal of Geophysical Research
King M
(2011)
Correction to "Ocean tides in the Weddell Sea: New observations on the Filchner-Ronne and Larsen C ice shelves and model validation"
in Journal of Geophysical Research
Kuipers Munneke P
(2017)
Observationally constrained surface mass balance of Larsen C Ice Shelf, Antarctica
Kuipers Munneke P
(2017)
Observationally constrained surface mass balance of Larsen C ice shelf, Antarctica
in The Cryosphere
Kulessa B
(2019)
Seawater softening of suture zones inhibits fracture propagation in Antarctic ice shelves.
in Nature communications
Kulessa B
(2014)
Marine ice regulates the future stability of a large Antarctic ice shelf.
in Nature communications
Luckman A
(2014)
Surface melt and ponding on Larsen C Ice Shelf and the impact of föhn winds
in Antarctic Science
Luckman A
(2010)
Persistent iceberg groundings in the western Weddell Sea, Antarctica
in Remote Sensing of Environment
Luckman A
(2012)
Basal crevasses in Larsen C Ice Shelf and implications for their global abundance
in The Cryosphere
Description | The project set out to discover how stable the Larsen C ice shelf on the Antarctic Peninsula is, based on a combination of field measurements, satellite remote sensing, numerical ice shelf modelling and fracture mechanics calculations. We completed all of these objectives and came to the important conclusion that the ice shelf is stable in its present condition, especially because so-called suture zones fuse together the ice tongues discharged by individual glaciers into the ocean. Suture zones appear to be composed of particularly soft ice and thus difficult to break, making the advance of ice shelf fractures less likely. Two major potential Achilles Heels exist, however, in the form of 1. A warming ocean, melting the underside of the ice shelf. This would be particularly problematic for the suture zones whose softest and thus 'good' ice is currently understood to be frozen onto their bases. A warming ocean melting this ice would reduce the stabilising effect of the suture zones. 2. 'Pinning points' - regions of elevated bathymetry on which the ice shelf is grounded and thus stabilised. If the ice shelf were to retreat from such pinning points then disintegration becomes more likely. This is of particular concern if the ice shelf were to retreat from the Bawden ice rise in the northeast. Our research has revealed an urgent need to drill into Antarctic ice shelf suture zones and extract and mechanically test the ice, so that their stabilising influence can confidently be included in ice sheet models. |
Exploitation Route | Our research is most significant to glaciologists, oceanographers and biological and climate scientists. We have published many papers based on this research in a major bid to disseminate it to these communities. We are keen that our findings are included in ice sheet models that seek to predict the future contribution of the Antarctic Ice Sheet to sea level rise - the latter being of great interest to policy makers and coastal protection planning and construction projects. |
Sectors | Construction,Education,Environment,Government, Democracy and Justice |
Description | ICE-SHELF CONTROL OF ANTARCTICA'S SEA LEVEL RISE CONTRIBUTION OVER THE 21ST CENTURY |
Amount | £111,684 (GBP) |
Funding ID | 2016-ENV-PostDoc-Swansea University-Thompson Sarah |
Organisation | AXA |
Sector | Private |
Country | France |
Start | 01/2017 |
End | 03/2019 |
Description | Ice shelf stress response to large iceberg calving |
Amount | £52,251 (GBP) |
Funding ID | NE/R012334/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 10/2017 |
End | 04/2019 |
Description | Impact of surface melt and ponding on ice shelf dynamics and stability |
Amount | £507,533 (GBP) |
Funding ID | NE/L005409/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 04/2014 |
End | 10/2017 |
Description | Quantifying the role of marine ice in Larsen C ice shelf dynamics |
Amount | £49,219 (GBP) |
Funding ID | NE/I016678/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 10/2011 |
End | 04/2012 |
Title | Seismic refraction data, Antarctic Peninsula, Larsen C Ice Shelf, Joerg Peninsula Suture Zone / Solberg Inlet Ice Shelf Unit, November-December 2008 |
Description | Walk-away seismic reflection surveys were conducted in two locations on and to the south of (i.e. on the Solberg Inlet derived meteoric ice shelf unit) the suture zone emanating from the Joerg Peninsula on the Larsen C Ice Shelf, approximately 95 km downflow of the peninsula's tip. The data were collected as part of NERC Project SOLIS. Funding was provided by NERC Standard Grant 'Present and future stability of Larsen C Ice Shelf', 2008-2011, NERC Reference NE/E012914/1. |
Type Of Material | Database/Collection of data |
Year Produced | 2019 |
Provided To Others? | Yes |