Geosciences

Antarctica — our fifth largest continent — is 58-times the size of the UK. Buried beneath the snow and ice that cover more than 99% of its surface are chains of mountains the size of the Alps, while around the edge of the continent, and running across its centre, are other large mountain ranges that rise above the ice.

Geologists have studied the rocks in these mountains for more than a century. These rocks reveal that Antarctica has moved vast distances over millions of years. More than 500 million years ago, Antarctica straddled the equator, and the warm, shallow seas that covered the continent supported trilobites and other organisms long since extinct.

For hundreds of millions of years, Antarctica was locked in the centre of a giant continent called Gondwana. Around 150 million years ago, this supercontinent began to split apart, forming the modern continents of Australia, India, South America and Africa. At that time, instead of ice and snow, Antarctica was covered in dense forest and dinosaurs roamed its coastal plains.

Rocks and fossils tell us that the continent began to cool about 80 million years ago and around 35 million years ago, a vast ice sheet blanketed East Antarctica.

Locked in Antarctica’s rocks and in the sea bed around the continent is an unparalleled record of how the Earth’s climate has changed over millions of years. During the past 50 years, geologists at British Antarctic Survey (BAS) have built up the world’s largest archive of Antarctic rocks and fossils and made major contributions to our understanding of Antarctica’s ancient history.

Today, using BAS’s Royal Research Ship James Clark Ross to carry out surveys at sea and BAS aircraft to study remote corners of the continent, BAS geologists are using these ancient records to help predict how future climate change will affect not only Antarctica, but also the rest of the world.

Scientists at BAS are using advanced computer models to show what the Antarctic may have looked like 3 million years ago. The models suggest that during the mid-Pliocene warm period, the ice retreated significantly from the edges of the continent and was replaced by a sparse tundra vegetation. That a rise in temperature of only a few degrees centigrade had such a profound effect on Antarctica is a stark reminder of what might happen in the near future.