Antarctica is the 5th largest continent on Earth with up to 98% of it being covered with thick ice and snow.
Its unique position in the high latitudes of the Southern Hemisphere means that almost all of Antarctica has temperatures below freezing all year long. It also means that in winter it is in complete darkness for 24 hours a day. And in the summer months, the sun barely sets.
Antarctica as a Continent
Unlike the Arctic in the Northern Hemisphere which is ice floating on water, Antarctica is a continent with bedrock under the thick ice sheet.
Scientists have used satellite data to produce maps to show what Antarctica is like beneath the ice. This has shown that the bedrock is made up of 5 large land masses with islands surrounding them.
Antarctica’s Icy Features
Antarctica hosts a range of fascinating icy features. It is one of only two places on Earth with an ice sheet. Ice sheets are large areas of thick ice, more than 50,000 km2.
The coastline is fringed with a series of ice shelves which are floating extensions of land ice. These are important glacial features as they can ‘hold back’ the ice on the land. This helps to stop the land ice from flowing into the sea. Sometimes, these ice shelves can calve into icebergs which float around in the surrounding ocean.
There are also extensive stretches of sea ice (frozen sea water, detached from the land) surrounding Antarctica. Sea ice is used for a range of wildlife, including krill and Emperor Penguins. Sea ice changes seasonally, scientists are now showing that climate change is affecting the timing and extent of sea ice.
Icebergs are the chunks of ice that have broken off (‘calved’) from the mainland glaciers and ice sheets and floated away into the ocean. You can see some icebergs floating in the water, surrounded by sea ice, in the photograph above.
Because ice is close to, but slightly less, dense than water, most of the iceberg’s mass is below water and only a little bit of it floats above the water. In fact, 9/10ths of the mass of the iceberg are below water!
You can draw your own iceberg here, and see how it would float:
The gallery below shows some of the beautiful and evocative icebergs from around Antarctica.