Geological Uplift Explains Why Antarctica Froze Millions of Years Before the Arctic

A new study published in Science reveals that Antarctica's extensive ice coverage formed millions of years before the Arctic due to geological uplift deep within the Earth. This research resolves a longstanding climate puzzle: how Antarctica developed a massive ice sheet when global temperatures were about 5 degrees Celsius warmer than today.

The study shows that powerful geological processes during the breakup of the supercontinent Gondwana, which included Antarctica, Africa, South America, Australia, the Arabian Peninsula, and the Indian subcontinent, caused significant uplift of East Antarctica's terrain over more than 100 million years. This uplift created cliffs, plateaus, and mountainous regions that allowed snow and ice to accumulate and persist, even in a relatively warm climate. The ice sheet began forming around 34 million years ago.

Researchers used computational models to reconstruct East Antarctica's surface evolution, discovering that "mantle waves", slow-moving hot rock flows beneath the Earth's crust, gradually raised the land above 2 kilometers, the critical height for glacier formation. This uplift explains why Antarctica's ice sheet formed much earlier than the Arctic's, where large ice sheets only appeared about 5 million years ago due to lower elevations.

The study also highlights a climate feedback effect: as the Antarctic ice sheet expanded, its bright surface reflected more sunlight, further cooling the region and lowering global temperatures by approximately 1 degree Celsius. Additionally, the cooling reduced atmospheric water vapor, weakening the greenhouse effect and enabling further ice growth.

Lead researcher Professor Thomas Gernon of the University of Southampton emphasized that deep Earth processes played a crucial role in shaping early landscapes and ice formation. Understanding these mechanisms is vital for interpreting Earth's ancient ice ages and anticipating future climate shifts.