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02/04/2025 09:00

Not Actually Eternal – Antarctic Ice Research

Merle El-Khatib Presse- und Öffentlichkeitsarbeit
U Bremen Research Alliance e.V.

The formation of the Antarctic Ice Sheet occurred differently than was previously assumed. An international team led by U Bremen Research Alliance researchers made a surprising discovery using a unique drill core and elaborate modeling methods. In the fight against climate change, this is not good news.

To the inexperienced eye, the drill core that Dr. Johann Klages shows in a lab at the Alfred Wegener-Institute, Helmholtz Centre for Polar and Marine Research (AWI) looks like an oversized coil of clay for children to play with. Nothing about this dark, solid, finely grained, smooth-surfaced sample gives away the fact that it is 33.8 million years old and a unique testament of our climate history.

Klages, however, immediately recognized that he had found something special when the sediment was brought to the surface from the 850-meter-depths of the Amundsen Sea. “The color indicated that this was organic material,” the sedimentologist explains. But where would these plant remnants come from in the icy desert of Antarctica?

The drill core, obtained during a 2017 expedition to West Antarctica with the Polarstern research vessel, turns previous discoveries about the dawn of the icy continent’s glaciation upside down. Until this discovery, researchers assumed that the Antarctic Ice Sheet was formed from the center outward around 34 million years ago, during a time of fundamental climate shifts that influence the global climate to this day. If this were the case, the sediment would have been coarser, and there would have been no traces of pollen or spores.

Based on the analysis of the sediment core, an international team of researchers began a climate reconstruction, which according to Klages, is the only one of its kind worldwide. The researchers supplemented their model with data about climate conditions, water and air temperatures, the presence of ice, and precipitation and refined it. The result, which is described in a recent study published in the prestigious journal Science, is clear. Glaciation initially began in the mountainous coastal regions of East Antarctica, then spread to the hinterlands, and slowly to West Antarctica – over a span of about seven million years.

“Although East Antarctica was covered in ice, beech trees were still growing in the west and the average annual temperature was five or six degrees Celsius,” says Klages. Above all, the analyses show that the ice sheet in West Antarctica not only formed much later, but is also much more susceptible to the effects of outside influences and climate change. “Even a minimal rise in temperatures is sufficient to melt the ice,” the researcher emphasizes. “That is a cause for concern.”

The largest contiguous ice mass on Earth is about one and a half times the size of Europe. The Antarctic Ice Sheet is up to 4.5 kilometers thick, and cools the water masses of the oceans like a giant refrigerator. It also influences currents, water temperatures, and winds, thereby controlling the Earth’s climate while simultaneously being very vulnerable to environmental change.

This is especially true in West Antarctica. While 85 percent of East Antarctica’s ice sheet is above sea level, the opposite is true in the west. Extremely salty and increasingly warmer ocean waters are hollowing out the ice. As a result, huge tabular icebergs are breaking off in West Antarctica, and the eternal ice continues to melt and recede. “This sets in motion a self-perpetuating process that many believe is unstoppable,” says Klages.

If the glaciers around the Amundsen Sea from which the researchers obtained the drill core were to melt, global sea levels would rise by one and a half meters. “If the entire West Antarctic Ice Sheet breaks off, this increase would be three and a half to five meters,” stresses Klages, emphasizing the short time period in which these changes have occurred.

All of this has happened in the last 150 years, which is hardly more than the blink of an eye in the Earth’s history. A century and a half is roughly equivalent to the time in which humanity has been extracting and processing fossil fuels from the Earth’s crust that had been deposited there over millions of years. “This is happening in an unprecedented way and at an unprecedented rate. We have begun an enormous experiment with an uncertain outcome,” says Klages. No one knows what this will do to our climate or to us, and what this will mean for our future. “Our focus is on protecting humans. The Earth really does not care what we do here.”

Prof. Dr. Heiko Pälike and Dr. Torsten Bickert from the University of Bremen’s MARUM – Center for Marine Environmental Sciences share this view. The paleo-oceanographer and the geoscientist were part of the expedition team and coauthors of the scientific study, as was their colleague Dr. Jürgen Titschack. They first scanned the six-centimeter diameter core using computed tomography in the Bremen-Mitte hospital, which is a partner of the institute, to get a complete and unobstructed view of important components such as root remnants before later cutting the core lengthwise.

The innovative approach that enabled the drill core retrieval is the MeBo70 seabed drill rig, which was used for the first time during the Polarstern’s expedition to Antarctica. It was developed by the University of Bremen’s MARUM, which, like AWI, is part of the U Bremen Research Alliance. Without its rotating cutterhead, drilling into the hard and heavily compressed soil in this region and bringing five sediment cores with a total length of ten meters to the water’s surface at the drilling site would not have been possible.

For the sedimentologist Klages, MARUM’s MeBo70 is a good example of how the individual members of the U Bremen Research Alliance complement and strengthen each other’s work. “The research environment in Bremen is unique, and not just from a technical point of view. Our alliance covers many areas of expertise. I honestly cannot imagine better working conditions. Everyone works with great motivation and conviction.”

This exciting article about the contribution made to the project by researchers from member institutions of the U Bremen Research Alliance was recently published in the science magazine "Impact" of the U Bremen Research Alliance: https://www.bremen-research.de/en/impressions/antarctic-ice

Contact:

Merle El-Khatib
Communication und marketing
Tel.: +49 421 218 60046
merle.el-khatib@vw.uni-bremen.de

About UBRA:

The University of Bremen and twelve federal and state financed non-university research institutes cooperate within the U Bremen Research Alliance. The Alliance includes research institutes of the four major German science organizations, i.e. Fraunhofer Society, Helmholtz Association, Leibniz Association and Max Planck Society, as well as the German Research Center for Artificial Intelligence.

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Original publication:

Impact - The U Bremen Research Alliance science ma­ga­zine Issue 11 (in German)

Since 2019 the Impact science magazine provides an exciting insight into the effects of cooperative research in Bremen. "Not Actually Eternal – Antarctic Ice Research" was published in issue 11 (January 2025) (in German).

https://www.bremen-research.de/fileadmin/user_upload/Einblicke/Impact_11/UBRA_Im...

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More information:

https://www.bremen-research.de/en/impressions/antarctic-ice

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The Polarstern research vessel in front of a large iceberg in Antarctica’s Pine Island Bay
Johann Klages
Alfred-Wegener-Institut

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Dr. Johann Klages analyzes a sediment probe in his office
Jens Lehmkühler
U Bremen Research Alliance

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Criteria of this press release:
Journalists, Scientists and scholars, Students, Teachers and pupils, all interested persons
Environment / ecology, Geosciences, Oceanology / climate
transregional, national
Miscellaneous scientific news/publications, Transfer of Science or Research
English

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