Scientists may have uncovered a major piece of the puzzle behind one of Earth’s long standing climate mysteries: why Antarctica became covered in ice millions of years before the Arctic.
A new international study published in Science suggests that powerful geological forces deep inside the Earth gradually lifted East Antarctica over more than 100 million years. The rising landscape created high mountains and plateaus cold enough for snow and ice to survive year after year, eventually helping form the vast East Antarctic Ice Sheet around 34 million years ago.
The research led by the University of Southampton, challenges the idea that falling carbon dioxide levels and global cooling alone triggered Antarctica’s transformation into an icy continent.
Scientists used computer models to reconstruct how East Antarctica’s landscape evolved over the past 100 million years. Their findings point to slow moving underground disturbances known as “mantle waves,” which travelled beneath the continent after Antarctica began separating from Africa during the Jurassic period.
As these waves moved through Earth’s interior, they gradually pushed large parts of East Antarctica upward, helping create a vast elevated plateau and raising the Gamburtsev Mountains.
By around 45 million years ago, large areas of East Antarctica had reached elevations of about two kilometres the study found. At these heights, temperatures were cold enough for snow to survive through the summer and gradually accumulate into glaciers.
Over time, these glaciers expanded and merged, eventually forming the East Antarctic Ice Sheet now the largest ice sheet on Earth.
The findings could also explain why Antarctica froze long before the Arctic. Antarctica became heavily glaciated around 34 million years ago, while major ice sheets in the Northern Hemisphere developed only within the past five million years.
Researchers say geography played a critical role. While declining atmospheric carbon dioxide helped cool the planet, Antarctica had already gained a major advantage because geological processes had lifted its land to higher colder elevations.
Once the ice sheet began to grow, a powerful feedback process accelerated the cooling. The bright surface of ice reflected more sunlight back into space, further lowering temperatures. Scientists estimate this ice-albedo effect contributed to about 1°C of additional global cooling.
Another feedback mechanism also strengthened the process. As temperatures dropped, the atmosphere held less water vapour a greenhouse gas that traps heat allowing further cooling and helping the ice spread from the mountains toward Antarctica’s coastline.
The study suggests that the formation of major ice sheets may depend not only on climate conditions but also on geological forces that prepare landscapes for glaciation.
Researchers say the findings could improve understanding of ancient ice ages and future climate tipping points by showing how processes deep within Earth can influence when and where major changes in the planet’s climate become possible.