On November 16, an international team of researchers and drilling experts will set out from Christchurch, New Zealand, for Antarctica to drill up to 200 metres into the seabed beneath the inner Ross Ice Shelf. The team aims to obtain geological records of changing sediments that reflect environmental conditions at the time of their formation in a warmer world than today. The hope is that these records will provide important insights into West Antarctica's past, allowing us to learn more about Antarctica's potential future contribution to sea level rise.
Recent scientific research has shown that the warming Southern Ocean will accelerate the melting of large portions of the West Antarctic Ice Sheet (WAIS) - even today, as a consequence of the accumulation of greenhouse gases in the atmosphere to date.
If completely melted, the WAIS contains enough ice to raise sea level by up to 5 metres. However, it is not yet certain how much and how fast West Antarctic ice will melt. While parts of the WAIS appear to be highly vulnerable, it remains unclear when and under what climatic conditions the large ice shelves that stabilize the ice sheet will be lost. Finding answers to this will require sediments from regions near the center of West Antarctica that were deposited during past periods that were warmer than today. These sediments contain environmental information that is critical for the predictions but has not been accessible until now.
"We know more about the rocks and composition of the Moon than we do about the land beneath the West Antarctic Ice Sheet," says micropaleontologist Denise Kulhanek (Kiel University), one of the lead scientists on the SWAIS 2C project. Since the first landing in 1969, astronauts have collected more than 2,400 rock and mineral samples from various locations on the moon. However, under the ice cover of West Antarctica, there are only 13 sites where scientists and researchers have collected geological samples. Now, on Nov. 16, an international team of researchers and drilling experts will set out from Christchurch for Antarctica to change that.
The international research project, Sensitivity of the West Antarctic Ice Sheet to Two Degrees of Warming (SWAIS 2C), will determine whether the Ross Ice Shelf and West Antarctic Ice Sheet could melt if Earth's average surface temperature is 2 °C above pre-industrial levels.
"In the Paris Agreement, we committed to keeping global average temperatures well below 2°C compared to pre-industrial conditions. Models tell us that the West Antarctic Ice Sheet will collapse once this value is exceeded. So far, however, this cannot be confirmed – simply because we do not yet have sound geological evidence that would allow us to define the behavior of the ice sheet during past warm periods," says Johann P. Klages, marine geologist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), German co-coordinator and member of the SWAIS 2C science team.
To learn more about Antarctica's potential contribution to sea level rise, a team of drilling, engineering and research experts will travel approximately 800 kilometers by traverse and aircraft to the southeastern edge of the Ross Ice Shelf. There, they will drill up to 200 meters into the seafloor to obtain geologic records of changing deposits that reflect environmental conditions at the time they formed. The hope is that these records will provide important insights into West Antarctica's past and the future of our planet.
"We will use a custom-built hot water drill to melt a 35-centimeter-diameter hole through 590 meters of thick ice, then move through 50 meters of ocean water to the site where the ice sheet broke away from its bed and created new ocean floor," says Andreas Läufer, geologist at the Federal Institute for Geology and Natural Resources (BGR), German coordinator and member of the SWAIS 2C science team.
"There, we will then position a special sediment coring system over the hole, lower a hollow drilling system to the seafloor, and drill to depth for hopefully obtaining long sediment records from West Antarctica's past," says Darcy Mandeno of the Antarctic Research Centre in Wellington, New Zealand, leader of the drilling effort for SWAIS 2C.
Field work in Antarctica will begin in November 2023 on the Kamb Ice Shelf and continue through January 2024. A second field season will begin in November 2024 on the Crary ice margin.
Background SWAIS2C project
More than 120 people from about 35 international research institutions in ten countries are collaborating on the SWAIS 2C project, including about 25 early career researchers. SWAIS2C follows on from other successful international Antarctic research programs such as ANDRILL.
The work is funded by the Natural Environment Research Council, the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, the German Federal Institute for Geosciences and Natural Resources, the National Science Foundation (NSF-2035029, 2034719, 2034883, 2034990, 2035035, and 2035138), the German Research Foundation (KU 4292/1-1, MU 3670/3-1, KL 3314/4-1), the Istituto Nazionale di Geofisica e Vulcanologia, the Korea Polar Research Institute, the National Institute of Polar Research, the Antarctic Science Platform (ANTA1801), the Leibniz 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 Program (ICDP). The total cost of the project for operations and logistics is $5.4 million. The AWI and the BGR together contribute approximately 10% for the realization of the project. The AWI is scientifically represented by Johann Klages, Juliane Müller, Karsten Gohl and Olaf Eisen, and the BGR by Andreas Läufer and Nikola Koglin.
Logistical support is provided by Antarctica New Zealand (K862A-2324, K862A-2425) in collaboration with the United States Antarctic Program. Drilling is funded and supported by ICDP. The project leader for SWAIS 2C is GNS Science and the drilling contractor is Te Herenga Waka-Victoria University of Wellington.
General background information
The average surface temperature of the Earth has warmed by 1.2 °C since the Industrial Revolution (1850), due to human activities such as the burning of fossil fuels (coal, oil, and natural gas). At the same time, sea levels around the world have risen by an average of 20 cm, primarily due to the expansion of the oceans as they absorb heat and the melting of our planet's glaciers, land ice caps, and ice sheets.
Further warming of 1.4 to 4.4°C is expected by 2100 - the magnitude of the increase will depend on the socioeconomic choices society makes regarding its greenhouse gas emissions. An additional 30 cm of sea level rise is inevitable regardless of our emissions choices, but the rise could be as much as 1 or 2 m if we follow a high-emissions path and potential instabilities in Antarctic ice sheets come into play.
How sensitive Antarctica's large ice shelves - and the ice sheets behind them - are to warming between 1.5° and 2°C is a key element of research that will help better predict when and how much polar ice sheets might melt.
Scientists can look to the past for answers to this important question. Geologic reconstructions from around the world show that sea level was 6-9 m higher than today during the last interglacial about 125,000 years ago. The average surface temperature of the Earth at that time was 1-1.5 °C warmer than in pre-industrial times. These data suggest that parts or all of the West Antarctic Ice Sheet may have collapsed, indicating a potential sensitivity to temperatures we have already reached and are certain to reach in the coming decade. The goal of this project is to obtain robust, direct evidence of potential ice sheet collapse under a range of environmental conditions.
