One of the consequences of global warming is the melting of ice on the polar caps. The Arctic is more affected than the Antarctic, despite the occasional spectacular detachment at the edge of the Antarctic ice shelf.
Dwindling sea ice surfaces On the Arctic Sea, ice conditions vary widely from year to year. Sea ice is usually up to 3 metres thick and only pushes together locally as a pack ice up to 25 metres in thickness. It is possible to journey to the North Pole with powerful icebreakers and submarines. The changing conditions of the Arctic sea ice are now registered by weather satellites. As a result of global warming, the minimum extent of sea ice has decreased to 4.13 million km² in September 2007, in which it fell below the previous record minimum in 2005. This is not a single extreme condition, but a long-term trend. The melting ice sheets facilitate navigation through the Arctic on the Northwest and Northeast Passage. This would provide new shipping routes for the future, which would significantly reduce shipping costs in international trade. Between 1961 and 2003, the sea level has risen on average by 1.1 mm. The melting of glaciers and sea ice has annually contributed 0.5 mm to the melting of the Greenland ice cap, in contast with only 0.05 mm previously. M. Felsch, K. Lückemeier, V. Hochschild, E. Astor; Ü: C. Fleming