Share on:
07/03/2026 14:44
Why Did the Antarctic Ice Sheet Grow Millions of Years Before Arctic Ice?
The uplift of land due to rock droplets beneath the Antarctic plate allowed ice to grow and persist, significantly earlier than in the Arctic. This conclusion is drawn from a new study published in the journal Science, involving researchers from the GFZ Helmholtz Centre for Geosciences.
Unraveling the Puzzle of Asymmetric Glaciation
Approximately 34 million years ago, as global temperatures were about 5 degrees Celsius higher and the Arctic region remained ice-free, a massive ice sheet began to form on the Antarctic landmass. The Arctic did not see significant glaciation until around 30 million years later. A new study published in Science sheds light on this asymmetric glaciation of the poles, revealing that the answer lies deep within the Earth’s mantle. Mantle waves triggered uplift in the southern polar region, creating highlands necessary for snow and ice accumulation.
The Role of Mantle Waves
During the Jurassic period, approximately 201 to 143 million years ago, the breakup of Antarctica and Africa initiated powerful geological processes deep within the Earth. For 100 million years, much of East Antarctica was uplifted, leading to the formation of the ice sheet around 34 million years ago. Thomas Gernon, a geoscience professor at the University of Southampton, explains that as the Antarctic land surface rose, eternal ice accumulation became possible despite warmer surrounding oceans and global temperatures.
Modeling the Antarctic Landscape
Researchers utilized computational models to reconstruct the development of East Antarctica’s surface over the last 100 million years. These models indicate that mantle waves caused gradual uplift, creating a vast high plateau crowned by the Gamburtsev Mountains. Simulations suggested that around 45 million years ago, much of East Antarctica had reached a critical elevation of approximately 2 kilometers essential for the creation and expansion of mountain glaciers, eventually forming the East Antarctic Ice Sheet.
Understanding Polar Ice Asymmetry
This research contributes to understanding the striking asymmetry of polar ice. The Antarctic turned glacial around 34 million years ago, while large ice sheets in the Northern Hemisphere only emerged in the last 5 million years. While declining atmospheric carbon dioxide (CO2) levels are often considered a catalyst for Antarctic glaciation, the initial ice sheet formation occurred when the climate was still relatively mild. Gernon argues that if falling CO2 levels were the sole factor, the poles would react more symmetrically.
The Impact of Elevation on Ice Accumulation
Even slight increases in mountain height can determine whether snow persists through summer or melts away. Fifty million years ago, most of the Gamburtsev Mountains were below 1.5 kilometers. Yet, by 34 million years ago, nearly half of the mountain range had surpassed 2 kilometers, allowing for year-round snow and ice accumulation. This feedback loop, termed the “ice-albedo effect,” lowered global temperatures by approximately 1 degree Celsius, insufficient to spur the formation of Northern Hemisphere ice sheets.
Climate Feedback Loops
As the Antarctic cooled, another climate feedback loop emerged: colder air holds less water vapor, which typically insulates the Earth. As the atmosphere dried, this insulating effect weakened, further reducing temperatures. Together, these feedbacks allowed the Antarctic ice cap to expand from the mountains across the continent and reach the coastline.
Implications for Understanding Ice Ages
This study may reshape how we view the origins of ice ages. Gernon emphasizes that the Earth’s interior sets the stage for landscape glaciation and determines when and where significant climate shifts, like the glaciation of Antarctica, become feasible. This understanding is crucial for interpreting past ice ages and potential future tipping points in the climate system.
Please note that this text is based on a press release from the University of Southampton.
Contact for scientific information:
Original publication:
Thomas M. Gernon et al., Continental breakup–driven uplift instigated East Antarctic Ice Sheet formation. *Science*393, eadz6758 (2026). DOI:10.1126/science.adz6758
Images
Criteria of this press release:
Journalists
Geosciences, Oceanology / climate
transregional, national
Research results, Scientific Publications
German
