Millions of years ago, Antarctica wasn’t quite the ice box it is today. While still chilly by the rest of the world’s standards, the great southern continent likely had periods of relative warmth compared to modern temperatures.
To set the scene: the Americas and Australia were previously attached to Antarctica through land bridges. But everything changed roughly 34 million years ago when movements under the Earth’s crust propelled the landmass to split off.
This major separation, combined with a drop of carbon dioxide in the atmosphere around the time, may have kicked off a chain of events that concluded in the development of the massive ice sheets that still cover the land around the South Pole.
“Everything fits together by chance so that we actually get this outcome,” says Katharina Hochmuth, a geophysicist at the University of Leicester.
Ice and sediment cores have long shown that large ice sheets had ...
