Introduction to Antarctica

This article acknowledges funding from the Antarctic Science Bursary

What is Antarctica?

At the far south of our planet, beyond the farthest tips of Patagonia, South Africa, and New Zealand, lies a big white land – Antarctica. It’s white because of the ice and snow that covers most of this huge continent. In fact, ice covers almost all of Antarctica – only 2% of the land surface is ice-free, and that is covered in snow most of the time! This ice is the Antarctic Ice Sheet, the biggest mass of ice on our planet.

Antarctica is a continent, surrounded by an ocean, which freezes with sea ice. This is different to the Arctic, which is entirely ocean, covered in sea ice, and surrounded by continents.

Antarctica. An orthographic projection of NASA’s Blue Marble data set (1 km resolution global satellite composite). “MODIS observations of polar sea ice were combined with observations of Antarctica made by the National Oceanic and Atmospheric Administration’s AVHRR sensor—the Advanced Very High Resolution Radiometer.” Image was generated using a custom C program for handling the Blue Marble files, with orthographic projection formulas. Source: Wikiemedia Commons

The image below shows the Arctic Ocean and the Antarctic region, and shows how the sea ice varies between the two poles. The sea ice grows each winter and shrinks each summer as it melts. The seasons are opposite in the two poles; it is summer in the Arctic and Northern Hemisphere when it is winter in the Antarctic.

Map of seasonal sea ice extents in the Arctic and Antarctic. From the NSIDC.

How big is Antarctica?

Antarctica is a huge continent! If all the ice in Antarctica were to melt, sea levels would rise by 57.9 metres.

The picture below shows how big Antarctica is when compared to the UK. Antarctica covers 14 million km2, and you could fit the whole of the United States within its borders!

This image shows the outline of Antarctica compared with the UK. The floating ice shelves have a blue outline.

The image below shows how large Antarctica is compared with the USA (image from NASA).

In this still image, Antarctica is shown using the Landsat Image Mosaic of Antarctica (LIMA) data with the continental United States overlaid on top for size comparison.

Ice sheets, ice shelves, icebergs and sea ice

The Antarctic Ice Sheet is so big that we split it up into two parts – the West Antarctic Ice Sheet and the East Antarctic Ice Sheet. These ice sheets are on land, called grounded ice, and contain a huge volume of ice – around 60% of the all the fresh water on Earth!

A cartoon of an ice sheet feeding into an ice shelf, showing the grounding line (where the glacier begins to float).

At the edges of the ice sheets, the ice begins to float on sea water, called ice shelves. These ice shelves are important because they hold back ice in the ice sheet, stopping it from flowing and melting quickly. It’s so cold around the southern hemisphere that the sea is often frozen, which we call sea ice. This is different to the ice shelves because sea ice is thin, and not connected to the ice sheet.

This image of Antarctic sea ice is from the NASA Scientific Visualisation Studio, showing the Earth on September 21st 2005. Source: Wikimedia Commons.

Sometimes, a part of the thick ice shelf breaks off and floats away, and it becomes an iceberg. This breaking away event is called calving.

img_2894
Huge icebergs can break away from ice shelves. They can be tracked by radar and satellite.

Antarctic wildlife

You might think Antarctica is too cold for wildlife. But Antarctica and its seas are teeming with life! The most famous residents are penguins, who live on the land and hunt for fish in the sea. There are mammals too, such as seals, and the seas surrounding Antarctica are rich in plankton, fish, and whales. Many birds live on or fly around Antarctica too, feeding in the sea that surrounds the continent.

Emperor penguins. By Ian Duffy from UK – Animal PortraitsUploaded by Snowmanradio, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=9962254

People in Antarctica

Despite it being very cold all the time, some people live and work in Antarctica, but only temporarily. A lot of research happens on Antarctica, with scientists and engineers learning about the vast, icy continent, and developing technology that can cope with the cold climate. Because Antarctica is so remote, and has a unique and stunning landscape and wildlife, it attracts tourists from all over the world, who visit on ships to see the continent, or even climb and ski its mountains.

Bethan Davies doing scientific research on Glacier IJR45, Antarctica.