Mission for ancient climate clues beneath Antarctic ice gets underway

If it were to melt completely, the vast West Antarctic Ice Sheet (WAIS) holds enough ice to raise the global sea levels by 4 to 5 meters, or 13 to 16 feet.

The WAIS abuts the Ross Ice Shelf, the world’s largest floating ice mass, which serves as a buttress slowing the flow of glaciers and ice streams toward the sea. A warming climate threatens the future of this ice shelf, but scientists still don’t know the particular tipping point that could trigger its unsustainable melting and the subsequent loss of the adjoining ice sheet.

Enter an international team of scientists, including Binghamton University, State University of New York Associate Professor of Earth Sciences Molly Patterson. At a camp 400 miles from the nearest base in New Zealand, they will attempt to drill 500 meters through the Antarctic ice to gain critical insights about the sheet’s future in a warming world.

Known as Sensitivity of the West Antarctic Ice Sheet to 2°C, or SWAIS2C, the collaboration involves more than 120 scientists from 10 countries; the “on-ice” team is comprised of 29 scientists, drillers, engineers and Antarctic field specialists. This is the project’s third attempt to drill for a 200-meter sediment core — a series of cylindrical samples of mud and rocks — from the bedrock beneath 500 meters of ice at the Crary Ice Rise on the Ross Ice Shelf. 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,” said Patterson, the mission’s co-chief scientist.

In particular, they’re searching for microfossils of marine algae in the sediment, which would suggest open ocean conditions and the retreat of the Ross Ice Shelf.

No one has ever successfully obtained such a deep sediment core so far from a base and so close to the WAIS’ center. SWAIS2C has spent the past two Antarctic summers attempting to drill at KIS3, a site around 160 miles from Crary Ice Rise, but both attempts were thwarted by technical issues with the custom-designed drilling system.

“This is Antarctic frontier science, and what we’re trying to do is complex and hugely challenging from an engineering and logistical perspective, as well as being world-leading science. We’ve made great progress towards our goal over the first two seasons and have modified the drilling system for success this year,” said Huw Horgan, co-chief scientist from Te Herenga Waka – Victoria University of Wellington, New Zealand, and ETH Zurich, Switzerland. 

The 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 analyze the sediment to learn more about the ice rise’s recent history and the role it plays in stabilizing the shelf. There are indications that the ice at this site has become pinned and unpinned over the past 1,100 years. 

“Pinning points can play a critical role in stabilizing 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 Patterson.

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,” Horgan said.

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Notes to Editors: 

• 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