Polar regions as key regions for monitoring climate change


Changes in the Polar atmosphere-ice-ocean system observed in recent years have sparked intense discussions as to whether these changes represent episodic events or long-term shifts in the Arctic environment. Late 20th century concerns about future climate change mainly stem from the increasing concentration of greenhouse gasses in the atmosphere. Existing knowledge on Quaternary climate and Global Climate Models (GCMs) predict that the effect of any ongoing and future global climatic change should be amplified in the polar regions due to feedbacks in which variations in the extent of glaciers, snow, sea ice and permafrost as well as atmospheric greenhouse gases play key roles. In addition, variations in the thickness of sea-ice tend to reinforce surface atmospheric temperature anomalies by altering the heat and moisture transfer from the ocean to the atmosphere. Thus, during the last 15 years the Arctic has gained a prominent role in the scientific debate regarding global climatic change.

The alleged enhanched temperature increase at high latitudes is mainly due to two theoretial greenhouse mechanisms:

For the above reasons, an important enhanced greenhouse surface ‘fingerprint’ is usually considered to be enhanced warming in the polar and sub-polar regions, less warming in the tropics and sub-tropics, and least warming in equatorial regions. This is the basic reason for much renewed research interest in Arctic regions, and recent sub-continental scale analysis of meteorological data obtained during the observational period apparently lends empirical support to the alleged high climatic sensitivity of the Arctic (Giorgi 2002). Analyses by different GCMs specifically of an enhanced greenhouse effect all suggest that the Polar Regions now should be experiencing a much larger warming than registered in lower latitudes. Polyakov et al. (2002a, 2002b), however, recently presented updated observational trends and variations of Arctic climate and sea ice cover during the 20th century, which questions the modelled polar amplification of temperature changes observed by surface stations at lower latitudes. The cryosphere is a prominent feature of the Polar Regions, represented by snow, glaciers, sea ice and permafrost. The physical properties of snow and ice include high reflectivity, high latent heat required converting ice to liquid water, and the low thermal conductivity of snow and ice; these factors all contribute significantly to the characteristics of Polar climates.


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