1. The Antarctic Ice Sheets

2. Antarctic Geography Antarctica is a continent twice the size of Australia, or the USA plus Mexico, and 58 times the size of the British Isles, covering 14 million square km. 98% of the continent is covered by glacier ice. The average thickness of this ice is 2 km, and in many places thickness exceeds 4 km, reaching a maximum of 4.8 km.

3. Ice up to three miles (4500 m) thick Coldest surface temperature -89 degrees C Enough ice for each person in the world to have a block 180 m by 180 m by 180 m If all melted, sea level could rise 65 metres If all the glaciers doubled their speed of flow it would take 12,000 years for the ice to float into the Southern Ocean Antarctic ice

4. The Antarctic Ice Sheets

5. The ice sheet’s three main components: the East Antarctic ice sheet, mainly occupying ground above sea level and which is relatively stable the West Antarctic ice sheet, resting on a bed that is mainly below sea-level and which is vulnerable to catastrophic collapse the Antarctic Peninsula ice sheet, a relatively small volume of ice covering the land of the same name that stretches towards South America.

6. Stages in Antarctic ice sheet evolution The first full-scale ice sheet over East Antarctica, occurred around 34 million years ago (the Eocene/Oligocene transition), following thermal isolation of Antarctica Major fluctuations of the East Antarctic ice sheet from 34 to about 15 million years ago (Oligocene to mid Miocene), and growth of, the continental shelf.

7. Stages continued The ice sheet reaches a maximum size about 15 million years ago (mid-Miocene). The West Antarctic ice sheet may have developed for the first time. Large-scale reductions in the size of the ice sheet according to another group of scientists around 2-4 million years ago (Pliocene Epoch). Stable East Antarctic ice sheet, but ‘unstable’ west Antarctic ice sheet throughout the last 2 million years (Quaternary Period).

8. A small change in the size of the Antarctic ice sheet would be serious for sea level One small part of Antarctica is above freezing in the summer - the Antarctic Peninsula. The Antarctic Peninsula is warming and its coastline is changing Maps of Antarctica need updating regularly because of the changes to the coastline Antarctic ice and sea level rise

9. Antarctic ice continued The disintegration of ice shelves from the Antarctic Peninsula has had no effect on sea level Most of Antarctica is not warming In a warmer world more snow will fall over the Antarctic Enhanced Antarctic snowfall is possibly the only natural way that sea level rise can be slowed