Today I found out a number of interesting things about the Earth’s poles and their ice:
1) The Antarctic is colder than the Arctic. Since ice has not melted there yet, it is not currently contributing to sea level rise.
2) The melting of sea ice (as with much of the Arctic) does not contribute to sea level rise, as the floating ice already displaces the volume of water it would occupy if it melted. Therefore only the melting of land ice can raise sea levels (small glaciers and Greenland ice sheet).
3) In our warming world, temperature rises have been most marked in the polar Arctic regions. “Since 1980, the surface area of the Arctic sea ice in summer has formed from around four million square kilometres to about one and a half million square kilometres. The Arctic is a microcosm of climate change. It’s a place where changes in the Earth’s temperature have been felt most keenly.” (Mat Collins, University of Exeter).
Another key difference is that in September 2012:
- The Arctic had the smallest area of sea ice ever recorded by satellite
- The Antarctic had the largest area of sea ice ever recorded by satellite