Antarctica is a continent. The Antarctic Ice Sheet is on top of a huge land mass, whereas the Arctic is frozen sea ice.
Many of us know Antarctica as a land of ice and not much else. But hidden beneath the miles of glaciers and ice sheets lies a landmass that was last exposed 40 million years ago. What does this land look like, and what could we expect to find if we are still around to see what's under Antarctica's ice sheets?
Some areas (2% in fact) of Antarctica are ice free, so it is very easy to see that there is land present. However, in other places, the Antarctic Ice Sheet is thousands of meters thick.
Scientists therefore need to look underneath the ice to map the land. They can do this in several ways: physically drilling through the ice, using radar to look through the ice, and using seismic waves to bounce signals off the surface of the land beneath the ice.
The coloured map below was one of the first maps created to help scientists learn about the unexplored land beneath the Antarctic Ice Sheet. Over 50 years of satellite data have been used to create a single map of the subglacial bed elevation (the height of the land beneath the ice, above and below sea level).
The colours on the map represent the different heights above sea level, with the darkest reds and brown representing high mountains, some of which are more than 2800m high. The lighter and darker blues represent areas of land which are below sea level. You can see that some areas are more than 2000m below sea level.
How much ice is on Antarctica?
The ice on Antarctica is measured in gigatonnes (one billion tonnes). This is equivalent to 1 km cubed. Imagine a giant ice cube which is 1 km x 1 km x 1 km!
Antarctica has a total of 27 million gigatonnes - so that is a lot of ice!
Knowing this information is really important to understand the sea level rise potential of Antarctica. On average, 361 Gt is equivalent to 1mm global sea level rise. The whole of the Antarctic continent has been calculated to have almost 60m of sea level rise potential if it was all to melt.
Each of the different ice sheets on Antarctica have a different amount of sea level rise potential. The East Antarctic Ice Sheet has the greatest, with 53.3m, and the peninsula has the lowest with 0.2m. The West Antarctic Ice Sheet has 4.3m, which is quite low for the amount of ice on this ice sheet. This is because much of the ice on the West Antarctic Ice Sheet is below the current sea level, so it is already displacing water. Therefore, scientists only use ice above sea level to calculate sea level rise.
