How Rising Land Put Antarctica's Ice in Place First
Published: August 26, 19:32
Researchers have found that uplift of East Antarctica, triggered by waves in the planet's mantle, was the key reason the continent became ice-covered before the Arctic. About 34 million years ago, when global climates were warmer than today, broad areas of East Antarctica rose above the critical elevation of 2 km. That made it possible for snow to persist and accumulate, eventually creating an ice sheet. An international team used computer models to reconstruct East Antarctica's changing landscape over the last 100 million years. The uplift was set in motion after Antarctica separated from Africa in the Jurassic period; mantle movements then lifted a large portion of East Antarctica over more than 100 million years. The findings offer a geological backdrop for understanding why the two polar regions developed ice on different timelines.
How the Ice Sheet Took Shape
Antarctica's great ice sheet began to form about 34 million years ago, while Earth's temperature was roughly 5 °C warmer than present. Around 45 million years ago, large portions of East Antarctica had already crossed the 2 km elevation line. The Gamburtsev Mountains illustrate the process: they now lie buried beneath 1–3 km of ice, yet before 34 million years ago almost half of the Gamburtsev range stood higher than 2 km. Since air temperature falls by about 1 °C for every 100 meters of ascent, elevation clearly had a major effect on ice-sheet development.
Lower levels of atmospheric carbon dioxide were an important factor, but they do not by themselves explain why Antarctica froze over before the Arctic. The reflective effect of ice on sunlight may have reduced global temperatures by around 1 °C. The East Antarctic Ice Sheet is now the largest ice sheet on Earth, and its complete melting would raise global sea levels by about 52 meters.
Overall, the study highlights how geological processes helped shape the climate conditions that influenced the evolution of ice sheets in both Antarctica and the Arctic.
These findings may significantly affect our understanding of modern climate change, demonstrating just how closely geological and climatic forces interact over long timescales. A clearer grasp of these dynamics could improve predictions of future ice-sheet changes and sea-level rise, which is crucial for adapting to global warming.
Understanding the formation of ice sheets in Antarctica not only sheds light on the continent's unique geological history but also connects to ongoing research in the Arctic. A newly identified phenomenon in the Arctic has been found to significantly increase the number of cloud particles, potentially influencing climate patterns in both polar regions. For more on how these processes interact and affect global temperatures, see the details in our article about the recent findings in the Arctic.