Final answer:
The Antarctic ice sheet is much thicker and larger, covering 98% of the continent and holding 70% of the Earth's fresh water, whereas the Arctic's ice cap is smaller and composed primarily of water ice. Plant life can exist in non-ice portions of Antarctica, such as Marie Byrd Land, but not in the Arctic. Global warming could lead to significant sea-level rise through melting of these ice covers.
Step-by-step explanation:
The ice margins in the Arctic and Antarctic regions vary greatly due to their differing geographic and climatic conditions. The Antarctic ice sheet is significantly thicker, covering about 98% of the continent with ice that is up to a mile deep in places. This immense ice sheet holds about 70% of the Earth's fresh water. In contrast, the Arctic ice cap is much smaller and primarily composed of water ice, covering a large basin in the north polar region of Mars.
Another notable difference is that areas in Antarctica, such as Marie Byrd Land, are not covered by ice and can sustain plant life like mosses and lichens, whereas the northern ice cap remains relatively unchanged in size with no such exposed areas. The global warming phenomenon could result in the melting of these ice covers, especially in Antarctica, which would lead to a significant rise in sea levels, altering the current sea-ice extent.
Furthermore, during the winter season, Antarctica's ice sheet can double in size as it extends from the coastline, while the Arctic experiences a variable sea-ice extent, which can be observed through a trend or slope of a best-fit line when comparing data between the hemispheres.