Why did Antarctica become covered in ice as early as around 34 million years ago, whilst large parts of the Arctic remained largely ice-free for many millions of years to come? An international study offers a surprising explanation: processes deep within the Earth’s interior raised East Antarctica, thereby creating the crucial conditions for the formation of the massive ice sheet.
Falling carbon dioxide concentrations are regarded as a key trigger for the global cooling that occurred at that time. However, this has not, until now, fully explained why massive ice sheets were able to form so early on in Antarctica of all places.
An international research team led by the University of Southampton has now concluded that the landscape itself played a decisive role. The original study, led by Thomas M. Gernon, was published in 2026 in the journal Science. According to the study, so-called mantle waves within the Earth’s interior slowly raised parts of East Antarctica over millions of years. This led to the formation or elevation of large high plateaus and mountain ranges, including the Gamburtsev Mountains, which are now hidden beneath kilometres of ice.
Using computer models, the researchers reconstructed the evolution of the Antarctic landscape over approximately 100 million years. Around 50 million years ago, large parts of the Gamburtsev Mountains were still below 1,500 metres. By around 34 million years ago, however, vast areas had reached heights of more than 2,000 metres.
Snow was able to remain on the ground there even during the Antarctic summer. Permanent snowfields initially gave rise to mountain glaciers, which grew, expanded and eventually merged to form ever-larger ice sheets.
As glaciation increased, the cooling effect was further intensified. Snow and ice reflect significantly more solar radiation than dark rock. This ice albedo effect, in turn, facilitated the further spread of ice across the continent.
A comparison with the Arctic reveals a crucial difference: in the high northern latitudes at that time, there was a lack of land areas of comparable size and elevation on which snow could accumulate permanently and large glaciers could develop. Despite global cooling, a similarly thick ice sheet therefore did not initially form there. Large-scale glaciation of the Northern Hemisphere did not begin until many millions of years later.
The findings show that tectonics, landscape and climate together enabled the early glaciation of Antarctica. The Earth’s interior, so to speak, set the stage on which the vast East Antarctic Ice Sheet was later able to develop.
Heiner Kubny, PolarJournal