Recent climate projections (CMIP6) indicate that future warming of the Southern Ocean will inevitably accelerate the melting of a part of the ice sheet covering Western Antarctica (called WAIS - Western Antarctic Ice Sheet). Depending on the level of future carbon dioxide emissions, total melting of the western ice cap could result in a potential rise in mean sea levels of up to 5 m.
While we worry about rising sea levels, some melting mechanisms of the western ice sheet remain understudied, particularly regarding the impact of surrounding ocean warming: some sectors of this region appear extremely vulnerable to fluctuations in ocean temperatures , and many questions still remain about the climatic conditions that cause the contraction of the massive coastal ice shelves that stabilize the continent's glacial flows behind them.
A contribution to the resolution of these unknowns comes from the study of samples of sedimentary rocks taken from areas close to the center of West Antarctica and formed in times warmer than the current one. These geological records contain environmental information critical to understanding our future, but until now it has been nearly impossible to recover them.
“We have more knowledge about the rocks and composition of the Moon than we do about the bedrock beneath the West Antarctic Ice Sheet” says Richard Levy, one of the scientific coordinators of the SWAIS2C project.
Since the first landing in 1969, astronauts have collected over 2400 samples of rocks and minerals from various lunar sites; However, of the Antarctic bedrock, researchers and scientists have so far managed to collect only a few geological samples from 13 locations. However, this situation is destined to change thanks to the initiative of a team of researchers and drilling technicians who will leave Christchurch (NZ) for Antarctica on 16 November.
The international project called SWAIS2C, acronym for Sensitivity of the West Antarctic Ice Sheet to Two Degrees of Warming, is aimed at determining whether the Ross ice shelf and the WAIS they will merge following the expected increase in average global temperature of +2°C compared to that of the pre-industrial era.
"Although the goal of the Paris Climate Agreement is to limit global warming to +2°C, we do not yet know whether the WAIS will lose most of its ice even with just 1, 2 or 3 degrees more, with the resulting in an increase of several meters in mean sea level," says Tina van de Flierdt, another scientific coordinator of the SWAIS2C project.
To better understand Antarctica's potential contribution to mean sea level rise, a team of drillers, engineers and researchers will undertake a journey (by land and air) of approximately 800 km to the south-eastern edge of the Ross shelf . There they will carry out drilling up to about 200 m below the seabed to recover sediment cores that retain traces of the environmental changes in which they were formed; with the hope that they will provide information on the history of West Antarctica and the future of our planet.
“To drill through the 590m of ice on the Ross Shelf, we will use a specially designed 35cm diameter hot water probe; it will give us access to the marine environment below, 50 m deep and very close to the point where the profile of the ice shelf stops resting on the seabed and begins to float” says Richard Levy.
“At this point, we will lower a special sediment drilling system into the hole consisting of a drill rod equipped with a diamond head with the aim of recovering a core of sedimentary rocks from that area of the seabed”, says Darcy Mandeno, the director of drilling operations at SWAIS2C.
Field operations in Antarctica will begin in November 2023 at the Kamb glacier and will continue throughout 2024. A second drilling campaign will begin in November 2024 in a region of the Ross shelf called “Crary Ice Rise” and will be coordinated by Molly Patterson and Huw Horgan.
The SWAIS2C project team is made up of more than 120 people including 25 young researchers from 35 research institutions belonging to the following countries: New Zealand, United States, Germany, Austria, Italy, Japan, Spain, Republic of Korea, Holland and United Kingdom.
For Italy, the INGV (National Institute of Geophysics and Volcanology) plays a significant and leadership role in the SWAIS2C project, operating as a "Contributing Party" with a significant presence both in the Science Team and in communication, education and dissemination activities to the public. Researchers from various Italian universities and research institutions are also participating in the project, including the University of Siena, the University of Genoa, the University of Trieste and the OGS (National Institute of Oceanography and Experimental Geophysics).
The overall cost of the project is estimated at $5,4 million. The most significant funding has been provided by several entities, including the Natural Environment Research Council, the Alfred-Wegener-Institute Helmholtz Center for Polar and Marine Research, the Federal Institute for Geosciences and Natural Resources, the National Science Foundation (NSF- 2035029, 2034719, 2034883, 2034990, 2035035 and 2035138), the German Research Foundation (with grants KU 4292/1-1, MU 3670/3-1 and KL 3314/4-1), the National Institute of Geophysics and Volcanology, 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. SWAIS2C is the first scientific project of
The SWAIS2C project has been defined as "the discovery of our times" and hopes that the results will be useful in developing adaptation strategies to the inevitable rise in mean sea levels, while simultaneously contributing to efforts to mitigate greenhouse gas emissions.
"Our approach to coring is innovative and not without risks, but it is the only way we can obtain such important samples. If we are successful and can demonstrate that this new technology works, it will open up new opportunities to obtain further geological records of environmental changes and ice sheet dynamics in other remote regions of the Antarctic continent.” says Richard Levy.
"Obtaining samples from these remote regions of Antarctica will also allow us to better understand how the ice sheet will respond to future warming, which portions will melt first and which will remain intact. We will use the past to better understand our future. This knowledge is essential as humanity already grapples with the inevitable challenge of rising mean sea levels”, says Tina van de Flierdt.
“Everything we will collect and discover on this journey will be new for humanity and certainly important for understanding future average sea level rise,” says Richard Levy.
The average temperature of our planet has increased by 1.2 °C since the industrial revolution (1850) due to human activities which include the burning of fossil fuels (coal, oil and natural gas). At the same time, the average sea level has increased on average by 20 cm due to both the thermal expansion of the ocean masses which absorb the heat and as a result of the melting of glaciers, ice caps and ice shelves.
We expect further average global warming of between 1.4° and 4.4°C by 2100, the actual extent depending on the socio-economic decisions our societies make regarding greenhouse gas emissions. An average increase in sea level of 30 cm will still be inevitable regardless of these decisions, but the increase could also be equal to 1 or 2 m if emissions are such as to cause instability of the Antarctic ice sheet.
The ice shelves and the rear portion of the marine ice cap have a sensitivity to warming between 1.5° and 2°C. But understanding the exact level of this feature is a crucial element in accurately predicting when and how the ice sheet may melt.
Scientists are turning to the past to answer some important questions: Geological reconstructions around the world indicate that during the last interglacial period, 125.000 years ago, average sea levels were 6 m higher than today. At that time the average global temperature of our planet was 1-1.5°C warmer than the average temperature of the pre-industrial era. This data suggests that part or all of the WAIS may have collapsed, so it could potentially have a higher sensitivity to the temperatures we have already reached or will certainly reach in the next decade. This project intends to collect solid direct scientific evidence of the different environmental conditions in which glacial collapse phenomena potentially occur.