An international team has set up a remote camp on the ice 700 km from the nearest base (New Zealand’s Scott Base), to attempt to drill for mud and rocks holding critical insights about the fate of the West Antarctic Ice Sheet in our warming world.
The vast West Antarctic Ice Sheet holds enough ice to raise global sea level by 4-5 m if it melts completely. It is protected on one side by the Ross Ice Shelf, the world’s largest floating ice mass, that serves as a buttress slowing the flow of glaciers and ice streams towards the sea. As our climate warms, the Ross Ice Shelf is becoming increasingly vulnerable, but there is uncertainty around what global temperature increase will trigger unsustainable melting of the shelf, and the subsequent loss of the West Antarctic Ice Sheet.
Retrieving a geological record to provide direct evidence of this temperature tipping point is the challenge driving the SWAIS2C (Sensitivity of the West Antarctic Ice Sheet to 2°C) project, a collaboration between 10 countries (New Zealand, the United States, Germany, Australia, Italy, Japan, Spain, Republic of Korea, the Netherlands, and the United Kingdom) involving more than 120 scientists. From Germany there are researchers from the LIAG Institute for Applied Geophysics (LIAG, Hanover), the Federal Institute for Geosciences and Natural Resources (BGR, Hanover), the Alfred Wegener Institute (AWI, Bremerhaven) and Kiel University (CAU, Kiel) involved. An ‘on-ice’ team of 29 scientists, drillers, engineers and Antarctic field specialists have embarked on the project’s third attempt to drill for a 200 m sediment core – a series of cylindrical samples of mud and rocks – from the bedrock deep beneath 500 m of ice at the Crary Ice Rise on the Ross Ice Shelf. Dr Arne Ulfers will then be responsible for doing measurements in-situ in the borehole – this will be the first available data.
“The sediment core analyses and measurements in the borehole provide a spatially and temporally high-resolution picture of the geological deposits and the environmental conditions at that time,” explains Dr Arne Ulfers, geoscientist at the LIAG Institute for Applied Geophysics, who is the only researcher from Germany travelling to the camp on the ice this year.“ In short, we are conducting research as an interdisciplinary team in the archives of the past in order to better understand what the future might hold for the 680 million people living on the low-lying coasts of the world.” Along with a relatively recent geological record, the core is expected to contain layers of sediment laid down within the past 23 million years, containing periods in Earth’s history when temperatures were warmer than they are today.
“We’ll analyse the samples to collect environmental data about how the Ross Ice Shelf responded in these past times of warmth. This record from the past will help us build a much clearer picture of what temperature will trigger the retreat of the West Antarctic Ice Sheet and significant sea-level rise,” says Dr Andreas Läufer, geologist at the BGR, German coordinator and member of the SWAIS2C science team. “This will allow us to identify future 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.”
They’ll search for tiny microfossils of marine algae in the sediment, organisms that need light to survive. Their presence suggests open ocean conditions and the retreat of the Ross Ice Shelf.
AWI Sedimentologist Dr Johann P. Klages emphasises the scientific significance of the project for the Institute: "One of our key objectives is to understand how the West Antarctic ice sheet behaved during past warm climate phases with high CO₂ concentrations. SWAIS2C is directly linked to our Polarstern expedition “EvoWAIS”, planned for early 2027, during which we will investigate further evidence of earlier collapses of the ice sheet."
A challenging mission started
No one has ever successfully obtained such a deep sediment core so far from a base and so close to the centre of the West Antarctic Ice Sheet. SWAIS2C has spent the past two Antarctic summers attempting to drill at KIS3, a site around 260km from Crary Ice Rise, but both attempts were thwarted by technical issues with the custom-designed drilling system.
Crary Ice Rise is a ‘pinning-point’ for the Ross Ice Shelf, a place where the seabed below the floating ice shelf is elevated and meets the base of the ice, anchoring the ice shelf and resisting the flow of the ice away from the continent. The researchers will analyse the sediment to learn more about the recent history of the ice rise and the role it plays in stabilising the ice shelf. There are indications that the ice at this site has become pinned and unpinned over the past 1100 years.
“Pinning points can play a critical role in stabilising the ice shelf. By examining the underlying geology, we can better understand how this pinning point might behave in the future. This is particularly key as our climate continues to warm, and the ice shelf becomes more at risk of retreating inland,” says Kulhanek.
SWAIS2C’s third season is underway with an even greater sense of urgency. 2024 was the first calendar year in which the average increase in Earth’s annual surface temperature exceeded the 1.5°C target of the Paris Agreement.
“We are well on track to permanently cross this warming threshold in the next 5 to 10 years unless we curb global emissions. The information we’re seeking about when and how much of the West Antarctic Ice Sheet we will lose is vital to help the world better adapt and prepare for sea-level rise, especially for the 680 million people living in low-lying coastal areas,” says Horgan.
An extreme polar road trip followed by eight weeks living in tents on the snow
Drilling in the deep field so far from the nearest base requires a large amount of equipment, both for the drilling itself and the operations of the camp, which must be set-up from scratch.
The six member Antarctica New Zealand traverse crew departed New Zealand’s Scott Base on 8 November – operating 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 1100 km journey over the Ross Ice Shelf required the use of a Ground Penetrating Radar to help them detect and avoid treacherous crevasses.
Arriving at Crary Ice Rise 13 days later, the traverse team created a ‘skiway’ on the ice for ski-equipped aircraft, allowing the drillers and scientists to fly in (700 km ‘as the crow flies’). The team will live in tents on the snow, and work in shifts around the clock to make the most of the limited time at this hard-to-reach location.
More on SWAIS 2C
Videos, photos and graphics are available to download from this link, please check the credit requirements and terms of use information before use.
- The SWAIS2C Project Manager is Earth Sciences New Zealand, and the Drilling Services Provider is Te Herenga Waka—Victoria University of Wellington. Logistical support comes from Antarctica New Zealand (K862A-2324, K862A-2425, K862A-2526, K862B-2324, K862B-2425, K862B-2526) 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 120 scientists 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.
- Approximately 680 million people live near coasts exposed to hazards caused by sea-level rise. 30 cm of sea-level rise is unavoidable by 2100 but the increase may be as much as 1-2 m if we follow a high-emissions pathway.
- SWAIS2C’s first field season took place in the Antarctic summer of 2023/24 at KIS3 (Kamb Ice Stream), our second season took place at KIS3 in 2024/25. At this season’s site Crary Ice Rise (CIR) the Ross Ice Shelf sits directly on the bedrock, while at KIS3 there is a 55-metre ocean cavity below the ice shelf.
- SWAIS2C’s 2024/25 season at KIS3 is documented in this 15-minute video.
- For more information about SWAIS2C visit www.swais2c.aq