The Antarctic coastal zone is not simply the edge of the continent. It is a tightly coupled system where the ice from the ice sheet extends over the seabed, initially resting on it and further out floating as ice shelves. Here, mass, heat and nutrients are exchanged with the ocean through various processes. Even the smallest changes can have outsized consequences. Yet key coastal conditions remain poorly mapped as an international review published in the journal Reviews of Geophysics shows. It highlights key knowledge gaps and the need for improved observations at a pan-Antarctic scale. Scientists from the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), the GEOMAR Helmholtz Centre for Ocean Research Kiel, the Federal Institute for Geosciences and Natural Resources, and the universities of Kiel, Bremen, Tübingen, Dresden and Erlangen Nürnberg contributed to the review.
The paper brings together 80 scientists from 16 countries from across glaciology, oceanography, geophysics, and atmospheric science, coordinated through the Scientific Committee on Antarctic Research (SCAR) RINGS Action Group. RINGS is also endorsed by the Council of Managers of National Antarctic Programs (COMNAP), which ensures to provide logistics knowledge for efficient survey planning and better coordinate support when it is provided by national Antarctic programs. In the review, the researchers synthesized the current understanding of how ice, ocean, atmosphere, and solid earth interact in Antarctica’s coastal zone by combining existing observations, models, and theory. The results show persistent gaps in direct observations of coastal bed topography and sub-ice shelf cavities. However, these are crucial for making reliable predictions about the future of the Antarctic ice sheet and the consequences for the climate and global sea-level rise.
These incomplete data continue to limit estimates of Antarctic ice loss and future sea-level rise, as ice sheet models are highly sensitive to conditions at the coast. Even advanced models can produce misleading results when this data is missing or poorly constrained. While satellite observations provide powerful measurements of ice motion and surface change, they cannot observe the bedrock under ice from space. "Satellite data alone cannot reliably estimate ice loss into the ocean, and computer models alone cannot predict future changes. Both depend on accurate knowledge of bed topography. Observations like those proposed in this paper provide a key missing piece", says first author and the chair of the RINGS Action Group, Dr. Kenichi Matsuoka at the Norwegian Polar Institute.
“Over the last decades AWI established an outstanding expertise in airborne measurements of ice thickness, the ice bed, and the cavities beneath the ice shelf, which can help to close the knowledge gap in this critical zone where the ice sheet meets the ocean. However, currently available observations are still sparse and increase uncertainties in our process understanding and future projections” says Olaf Eisen, professor for glaciology at the AWI and the University of Bremen and German representative in RINGS and co-author of the review.
Because no single nation can achieve comprehensive coverage alone, the authors emphasize that international coordination is essential. “Uncoordinated surveys risk leaving gaps or duplicating effort. This paper provides an evidence-based framework to support coordinating RINGS activities under SCAR and COMNAP, helping to build more comprehensive datasets for improved sea-level projections”, Matsuoka says.
Co-author Naomi Krauzig, researcher in the Physical Oceanography Research Unit at GEOMAR, says: “In order to better predict future changes to the Antarctic ice sheet and their impact on the ocean, climate and sea level, we need long-term, coordinated measurement programmes and close international cooperation. Autonomous platforms offer new opportunities to gather urgently needed observational data, even during the Antarctic winter and in hard-to-reach regions beneath sea ice and, in particular, beneath ice shelves.”
Co-author Professor Jörg Ebbing, Head of the Satellites and Aerophysics Working Group at Kiel University, also assesses the current state of the data. The geophysicist focuses primarily on the interactions between ice and the solid Earth. “Information on the structure of the lithosphere – the outermost, solid rocky shell consisting of the Earth’s crust and the uppermost part of the mantle – is crucial for determining melt rates. We are still lacking a great deal of geophysical data in this area, which we intend to collect in future using new aircraft-based measurements.”
Co-author Dr Graeme Eagles, geophysicist at the AWI who has himself led RINGS flight campaigns, adds: “Thanks to the AWI’s outstanding measurement expertise on our polar aircraft and in collaboration with our German partners from federal agencies, Helmholtz Research Centres and universities, Germany is one of the major contributors and data providers for the international RINGS initiative. We are delighted that, in the coming season, we will be able to collect new observations in close collaboration with the polar research institutes in Norway and Japan.”
“Such internationally coordinated efforts can serve as a springboard for the next International Polar Year in 2032/33,” concludes Matsuoka.
Original publication
Original Publication:
Kenichi Matsuoka, Geir Moholdt, Jennifer Arthur, et al. Towards an improved understanding of the Antarctic coastal zone and its contribution to future global sea level. ESS Open Archive. 13 July 2025. DOI: 10.1029/2022RG000803
