Climate indicators

Both sea ice and ice on land can warn us of changes in global or regional climate and are therefore important climate indicators. Sea ice in the far north is undergoing radical change, signalling that the climate is not in balance. Land-based ice is melting in both north and south, showing that major changes are taking place.

About 15% of the world’s total sea surface is covered by ice part of the year; most of these areas are in the polar regions. Sea ice plays a significant role in the global climate system, and the ice both affects and is affected by global warming. When a change in climate alters conditions in the atmosphere and oceans, sea ice responds, giving a clear warning sign of global climate change. A range of processes, some of them interconnected, regulate how sea ice responds, and research over long time-scales is required to distinguish between the signals of climate and natural variability.

About 10% of the earth is covered by glaciers and ice caps, again mainly in polar regions. Ice on land is an important factor in the global climate system, particularly because of its impact on sea level, whereas melting of sea ice has no effect on sea level. Glaciers and ice caps respond to changes in the atmosphere and the sea when the climate changes, and thus also provide clear signs of global climate change. Glaciers, and particularly the large inland ice caps, also contain vital information about the earth’s climate back in time.

Snow and permafrost are other forms of ice that provide important climate signals in the northern hemisphere.


Climate research at the Norwegian Polar Institute has a special focus on sea ice, glaciers, oceanography and marine ecosystems, and much of this research is coordinated by Centre for Ice, Climate and Ecosystems (ICE).

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