◆Research findings by a group led by Professor Minoru Ikehara of the International Marine Core Research Institute have been published in *Nature Geoscience*
Release Date:
The melting of the Antarctic ice sheet triggers further melting
Based on an analysis of the causes of the massive melting of the Antarctic ice sheet that occurred 9,000 years ago,
Proposing a potential chain reaction of ice sheet melting in Antarctica in the future—
A research group led by Professor Minoru Ikehara of the International Institute for Marine Core Research has revealed, through extensive topographic and geological surveys of the East Antarctic coast and analysis of seafloor sediments, that approximately 9,000 years ago, the inflow of warm deep-ocean water into a bay caused the collapse of the East Antarctic coastal ice shelf (Note 1), which in turn triggered a rapid retreat of the East Antarctic ice sheet.Previous research by this group has shown that regional sea-level rise occurred along the East Antarctic coast during this period (Reference 1), and it is believed that the combination of sea-level rise and deep-water inflow triggered large-scale melting of the Antarctic ice sheet.
Furthermore, climate and ocean model simulations suggest that meltwater released from ice sheet melting in other regions, such as the Ross Ice Shelf, spread across the Southern Ocean, potentially intensifying the inflow of deep water.Of particular note is the finding that the spread of meltwater from Antarctic ice sheet melting may trigger a chain reaction of ice sheet melting in other regions—that is, the “tipping cascade” phenomenon (Note 2).These research findings not only contribute to elucidating the mechanisms behind large-scale Antarctic ice sheet melting but also provide critically important data for improving the accuracy of future predictions regarding Antarctic ice sheet melting and sea-level rise.
These findings were published in Nature Geoscience on November 7, 2025.
(Photo) A scene from the 61st Japanese Antarctic Research Expedition (2019–2020) showing the collection of seafloor sediment cores from the Antarctic research vessel "Shirase." A large cylindrical device (core sampler) is driven vertically into the seafloor and then retrieved to collect sediment samples.
(Note 1)
In coastal regions of polar areas such as Antarctica and Greenland, glaciers flowing from the mainland reach the sea and form massive sheets of ice up to several hundred meters thick that float on the water. These are called ice shelves.
(Note 2)
In recent years, the concept of a “tipping point”—a point at which changes in climate conditions cross a critical threshold, causing a rapid and irreversible shift to a different state—has garnered significant attention in the context of climate change.On the other hand, a “tipping cascade” refers to a phenomenon in which a climate change event (tipping point) in one region triggers another climate change event (tipping point) in a distant region, causing tipping points to cascade like dominoes and leading to large-scale changes. Specific examples of such phenomena include the weakening of deep ocean circulation and the melting of ice sheets; whether these cascades will actually occur remains a major research topic today.
Published in: Nature Geoscience
Title: Holocene Antarctic ice shelf collapse driven by meltwater release feedbacks
Author:
Yusuke Suganuma (Professor, Geosphere Research Group, National Institute of Polar Research / Professor, The Graduate University for Advanced Studies)
Takuya Itagi (Research Group Leader, National Institute of Advanced Industrial Science and Technology)
Yuki Haneda (Researcher, National Institute of Advanced Industrial Science and Technology)
Kazuya Sobara (Associate Researcher, Japan Agency for Marine-Earth Science and Technology)
Takashi Konagaya (Project Researcher, Institute of Atmospheric and Oceanic Research, The University of Tokyo; (currently) Project Researcher, Japan Agency for Marine-Earth Science and Technology)
Kenji Ishiwa (Assistant Professor, Geosphere Research Group, National Institute of Polar Research / Assistant Professor, Graduate University for Advanced Studies)
Takayuki Omori (Special Researcher, University of Tokyo Museum)
Minoru Ikehara (Professor, International Research Center for Marine Core Studies, Kochi University)
Rob McKay (Professor, Victoria University of Wellington)
Sai Seki (Associate Professor, Institute of Low Temperature Science, Hokkaido University)
Daisuke Hirano (Assistant Professor, Atmosphere and Hydrosphere Research Group, National Institute of Polar Research / Assistant Professor, Graduate University for Advanced Studies)
Masakazu Fujii (Assistant Professor, Geosphere Research Group, National Institute of Polar Research / Assistant Professor, Graduate University for Advanced Studies)
Yuichi Kato (Lecturer, International Research Center for Marine Core Science, Kochi University)
Atsuko Amano (Research Group Leader, National Institute of Advanced Industrial Science and Technology)
Yuki Tokuda (Associate Professor, Tottori University of Environmental Studies)
Hokuto Iwatani (Lecturer, Graduate School of Innovation Science, Yamaguchi University)
Katsuaki Suzuki (Principal Researcher, National Institute of Advanced Industrial Science and Technology)
Mikihiro Hirabayashi (Project Assistant Professor, Atmosphere-Hydrosphere Research Group, National Institute of Polar Research)
Hiroyuki Matsuzaki (Professor, University Museum and Archives, The University of Tokyo)
Takeyasu Yamagata (Research Associate, University Museum and Archives, The University of Tokyo)
Masao Iwai (Professor, International Research Center for Marine Core Studies, Kochi University)
Kota Kazuki (Associate Professor, Estuary Research Center, Shimane University)
Francisco J. Jimenez-Espejo (Spanish National Research Council, Researcher)
Hiroki Matsui (Assistant Professor, Graduate School of International Resource Studies, Akita University)
Koji Seike (Affiliated with a Research Group, National Institute of Advanced Industrial Science and Technology)
Motohito Kawamata (Researcher, Cold Region Foundation Engineering Research Group, Cold Region Civil Engineering Research Institute, Public Works Research Institute)
Naohiro Nishida (Associate Professor, Tokyo Gakugei University)
Yuto Ito (Special Researcher, Atmosphere-Hydrosphere Research Group, National Institute of Polar Research;
; Currently: Special Researcher, Graduate School of Frontier Sciences, The University of Tokyo)
Shin Sugiyama (Professor, Institute of Low Temperature Science / Arctic Research Center, Hokkaido University)
Junichi Okuno (Assistant Professor, Geosphere Research Group, National Institute of Polar Research / Assistant Professor, The Graduate University for Advanced Studies)
Nobunobu Sawagaki (Professor, Faculty of Sociology, Hosei University)
Ayako Abe (Professor, Institute of Atmospheric and Oceanic Physics, The University of Tokyo)
Shigeru Aoki (Professor, Institute of Low Temperature Science, Hokkaido University)
Hideki Miura (Professor, Aomori Public University)
DOI: 10.1038/s41561-025-01829-7
Publication Date: November 7, 2025, at 7:00 PM (Japan Standard Time)
This research was supported by JSPS KAKENHI grants (JP16H05739, JP17H06321, JP17H06318, JP19H00728,JP21KK0246, JP24H00026, JP24H02344), project grants from the National Institute of Polar Research (KP-7, KP306), and collaborative research grants from the International Marine Core Research Center at Kochi University (No. 20A040, 20B037, 22A007, 22B006).Field surveys and sample collection were conducted by the Japanese Antarctic Research Expeditions (22nd, 33rd, 47th, 57th, 59th, 61st, and 64th Expeditions).