The vast West Antarctic Ice Sheet holds enough ice to raise sea level by 4-5 m if it melts completely. Research has found a collapse might be inevitable for some parts of the West Antarctic Ice Sheet, such as the area around the ‘Doomsday Glacier’ (Thwaites Glacier) in the Amundsen Sea, due to the presence of warm water beneath it. In contrast, water underneath the large Ross Ice Shelf is still cold, so right now it serves as a stabilising buttress to the inland ice of other areas of the West Antarctic Ice Sheet. This could change with continued warming, but we do not know when this might happen because we lack direct evidence of if and when we this happened in the past.
Identifying past collapses of the ice sheet using geological data
Understanding what temperature will trigger unavoidable melt of the Ross Ice Shelf, and the subsequent collapse of the West Antarctic Ice Sheet, is critical for all of humanity. This is the challenge driving the scientists, drillers and Antarctic field specialists from 13 countries to come together as part of the SWAIS2C (Sensitivity of the West Antarctic Ice Sheet to 2°C of warming) project, and why the “on-ice” team of 27 will camp at the KIS3 drilling site this Antarctic summer.
“The West Antarctic Ice Sheet is one of the components in the Earth system that is most vulnerable to increasing warming. Yet we do not know when and how fast it will melt and raise global sea level by several metres,” says Dr Andreas Läufer, geologist at the BGR, German coordinator and member of the SWAIS2C science team.
To answer this question, SWAIS2C is seeking insights contained in sediment layered in the seafloor under the Ross Ice Shelf. To obtain this geological record the team must first melt a hole through around 580 m of the ice shelf. Then they will use a custom-designed drilling system to reach the seafloor, lowering the drill through the hole in the ice shelf, and then through a 55 m ocean cavity to reach the seabed. The drill will then collect sediment up to 200 m deep into the seabed.
This is no easy task – something the team knows all too well. Due to technical difficulties, their efforts to do so last year were thwarted after reaching the seafloor.
“We want to drill up to 200 meters into the underlying, most likely consolidated target sediment in the coming season. We hope that these sediments will give us more information about periods when the West Antarctic Ice Sheet was exposed to warmer and more CO2-rich conditions that are also predicted for the coming decades and centuries,” explains marine geologist Dr Johann Klages from the AWI, German co-coordinator and member of the SWAIS2C science team. "This will allow us to answer the following questions: How stable is the West Antarctic ice under these conditions and can we identify tipping points beyond which the ice sheet retreat can no longer be halted?” adds micropaleontologist Denise Kulhanek, Professor at Kiel University and one of the lead scientists on the SWAIS2C project, whose research is helping to understand past changes in ocean conditions and the extent of the West Antarctic ice sheet.
A German scientist on site: LIAG uses its borehole geophysics
In order to fully map the conditions in the past, geophysical measurements must be carried out in the borehole
“Sediment cores often come to the surface deformed or with parts missing. We use measurements within the borehole to record information about the sediment without gaps over the entire depth of the borehole as they were originally deposited,” explains Dr Arne Ulfers, scientist at LIAG and project manager for borehole geophysics, who is the only researcher from Germany to travel to the camp on the ice this year. "By analyzing the borehole data and comparing it with the data of the sediment cores, we can obtain a comprehensive spatial and temporal picture of the geological processes and the environmental conditions at the time. This allows us to deduce whether the sediments may have been deposited in an ice-free world. We’re using the past to help us prepare for our future."
The coveted core is expected to reach back hundreds of thousands of years, potentially even millions of years. Such a record would include the last interglacial period 125,000 years ago, when Earth was around 1.5°C warmer than pre-industrial temperatures – similar to the temperatures we’ve approached this year due to human-caused climate change.
The sequence of rocks and mud will reveal how the West Antarctic Ice Sheet behaved during this past time of warmer temperature. If the researchers find marine algae that lived in open ocean conditions, it’s likely the ice sheet had retreated at the time those sediments were deposited on the seafloor.
The team calls SWAIS2C “the discovery for our lifetime” and hopes the results will guide plans to adapt to unavoidable sea-level rise, while amplifying the imperative to mitigate global greenhouse gas emissions.
The mission for ‘the discovery for our lifetime’ begins with an extreme polar road trip
Drilling at a deep field research camp so far from the nearest base – New Zealand’s Scott Base – requires a large amount of gear, both for the drilling itself and the operations of the camp.
Six of Antarctica New Zealand’s camp crew departed Scott Base on 1 November on the traverse – a convoy of PistenBully polar vehicles towing the load of fuel, science and drilling equipment and supplies to sustain the camp for the approximately 8-week season. Their 1128 km journey is expected to take 15 days over the Ross Ice Shelf, the largest ice shelf on Earth, and requires Ground Penetrating Radar to help them detect and avoid treacherous crevasses.
Once they’ve arrived at KIS3 they’ll create a runway on the ice for ski-equipped aircraft, allowing the drillers and scientists to fly in (860 km ‘as the crow flies’) later in November.
Notes to Editors:
- KIS3 is a drilling site on the Kamb Ice Stream of Antarctica’s Siple Coast, the grounding zone of the West Antarctic Ice Sheet where the ice sheet begins to float as the Ross Ice Shelf.
- The SWAIS2C Project Manager is GNS Science and the Drilling Services Provider is Te Herenga Waka—Victoria University of Wellington. Logistical support comes from Antarctica New Zealand (K862A-2324, K862A-2425) in collaboration with the United States Antarctic Program. Drilling is partly funded and supported by the ICDP. Significant additional funding and in-kind contributions have been provided by the Natural Environment Research Council, Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Federal Institute for Geosciences and Natural Resources, National Science Foundation (NSF-2035029, 2034719, 2034883, 2034990, 2035035, and 2035138), German Research Foundation (grants KU 4292/1-1, MU 3670/3-1, KL 3314/4-1), Istituto Nazionale di Geofisica e Vulcanologia, Korea Polar Research Institute, National Institute of Polar Research, Antarctic Science Platform (ANTA1801), LIAG Institute for Applied Geophysics, AuScope, and the Australian and New Zealand IODP Consortium. This project is the first in Antarctica for the International Continental Scientific Drilling Project (ICDP), and follows on from other successful international Antarctic research programmes such as ANDRILL.
- More than 130 people from around 50 international research organisations are collaborating on the SWAIS2C project. SWAIS2C brings together researchers from New Zealand, the United States, Germany, Australia, Italy, Japan, Spain, Republic of Korea, the Netherlands, and the United Kingdom.
- Geological reconstructions from around the world indicate that during the last interglacial period 125,000 years ago, when Earth’s average surface temperature was 1 to 1.5°C warmer than pre-industrial, sea levels were ~6 m higher than today. This suggests that parts or all of the West Antarctic Ice Sheet may have collapsed, highlighting a potential sensitivity to temperatures that we have already reached, and will certainly experience in the coming decade. SWAIS2C aims to obtain robust, direct evidence for potential ice collapse under different environmental conditions.
- Approximately 680 million people around the world live in low-lying coastal regions and are exposed to hazards and impacts due to sea level rise.
For more information:
If required by the press, footage and images can be supplied or produced on site. Please send an e-mail to Greta Clasen, presse(at)leibniz-liag.de.
Scientific contact at LIAG
(on-ice probably from December to mid January)
Dr Arne Ulfers
Borehole geophysicist
Arne.Ulfers@liag-institut.de