Antarctica’s transformation into an ice-covered continent approximately 34 million years ago was driven by deep-Earth geological processes that elevated its surface, according to a study published in the journal Science. Researchers led by Professor Thomas Gernon of the University of Southampton found that “mantle waves”—slow-moving currents in the Earth’s interior—gradually pushed the East Antarctic landscape upward, creating high-altitude plateaus and mountain ranges like the Gamburtsev Mountains. This elevation triggered the onset of permanent glaciation by placing land at altitudes where temperatures remain low enough for snow to persist year-round, despite warmer global oceanic conditions.
How did geological activity trigger the ice age?
The research team utilized computer modeling to reconstruct 100 million years of landscape evolution on the East Antarctic continent. Their findings indicate that the breakup of Antarctica and Africa during the Jurassic period initiated the movement of mantle waves beneath the crust. These waves acted as a structural engine, lifting the terrain over millions of years. By 45 million years ago, large swaths of the continent had reached elevations exceeding 2 kilometers. This height was the critical threshold for ice accumulation; as Dr. Guy Paxman, a Royal Society University Research Fellow at Durham University, a co-author of the study, noted, air temperature drops by roughly 1°C for every 100 meters of elevation.
The “albedo effect” created a feedback loop once the ice formed. Because bright white ice reflects solar radiation back into space, the initial glaciation of Antarctica helped lower global temperatures by approximately 1 degree Celsius.
Why did the Arctic remain ice-free for millions of years longer?
While Antarctica began its deep freeze 34 million years ago, the Northern Hemisphere did not see extensive ice sheets until roughly 5 million years ago. The study attributes this disparity primarily to topography. Unlike the East Antarctic plateau, the landmasses in the Arctic were at significantly lower elevations. Even as atmospheric carbon dioxide levels dropped, the Arctic terrain lacked the necessary height to sustain year-round snow cover. This highlights that climate change alone is not the sole driver of glaciation; the physical structure of the Earth’s surface is a fundamental requirement for ice sheet formation.
Pro Tip: The Role of Topography in Climate Models
When analyzing historical climate data, scientists now focus more heavily on tectonic elevation. If a region is not high enough, fluctuations in greenhouse gases may not be sufficient to trigger permanent ice, regardless of how cold the atmosphere becomes.
What does this mean for future climate research?
Understanding the interplay between deep-Earth geology and surface climate provides a clearer picture of how our planet responds to shifts in atmospheric composition. By identifying the mechanisms that allowed Antarctica to become a frozen continent, researchers can better predict how modern landscapes might react to ongoing climate volatility. The study suggests that internal geological processes should be integrated into climate models to improve the accuracy of long-term environmental projections.
Frequently Asked Questions
Why did Antarctica freeze before the rest of the world?
Antarctica froze earlier because mantle waves pushed its interior to elevations above 2 kilometers. At this height, the air is cold enough to prevent snow from melting during the summer, allowing glaciers to accumulate.
What are mantle waves?
Mantle waves are slow-moving processes occurring in the hot layers of the Earth’s interior that gradually elevated the terrain.
Did carbon dioxide play a role in the glaciation?
The study notes that despite the drop in carbon dioxide levels, snow could not persist in the Arctic as effectively as on the high terrain of Antarctica.
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