New research published in Science suggests Antarctica's vast ice sheet did not emerge from cooling alone. Instead, deep geological forces and rising terrain may have helped prepare the continent for long-term glaciation millions of years before the Arctic followed.
Why Antarctica cooled first
East Antarctica holds the planet's largest ice sheet, yet scientists have long wondered why it froze around 34 million years ago while the Arctic remained mostly ice-free for roughly 25 million more years. Lower atmospheric carbon dioxide clearly mattered, but it could not fully explain the timing.
The study points to a second driver: the slow reshaping of Antarctica's landscape. After Antarctica separated from Africa as part of Gondwana, movement in Earth's mantle likely triggered mantle waves beneath the continent. Over millions of years, these deep geological ripples lifted parts of East Antarctica, especially inland regions.
Mountains as climate engines
Computer models indicate that this uplift raised the Gamburtsev Mountains above a key elevation threshold. Once the terrain climbed high enough, snow could survive summer seasons and gradually build into glaciers. By about 45 million years ago, the landscape may have been ready for ice to spread across the continent.
The process also created powerful feedback loops. Ice and snow reflected more sunlight than bare rock, reinforcing cooling, while colder air held less water vapor, reducing the greenhouse effect over the region. Together, these changes helped the ice sheet expand from mountain zones to the coast.
The findings also help explain why the Southern Ocean stayed warmer for so long and why the Arctic needed much more time, lower carbon dioxide, and deeper global cooling before major ice sheets could form there.
Beyond Antarctica, the study highlights a broader idea: Earth's deep interior can shape climate outcomes long before surface conditions fully align. That perspective may help scientists better understand how ice ages begin and how future landscapes could influence climate over geological time.
The study suggests that the planet's frozen future may depend not only on temperature, but also on the hidden architecture of the land beneath our feet.