zurück

 

The Sea Ice condition in the Arctic are normal
posted 24 September 2010

 A peer-reviewed paper published in the Canadian Journal of Earth Sciences finds that  the Arctic sea ice extent at the end of the 20th century was more extensive than most of the past 9000 years.[1] The results of this study show that sea-ice cover in the western Arctic Ocean has varied throughout the Holocene. More importantly, there have been times when sea-ice cover was less extensive than at the end of the 20th century.

That is not new. Even during the mid term of the Little Ice Age the ice cover was at least temporarily considerable less than during the last decades. Although the Arctic sea ice reached the lowest in history in June 2010 it recovered and surpassed other low-level-years (2007 & 2008) see the graphic from the Danish Meteorological Institute (24.Sept.2010).  

The paper discusses reasons for changes, for example:
___The influx of relatively fresh Pacific water via the Bering Strait may have also played an important role in the strength of the halocline in the western Arctic, as it does today; and

___Thus, we suggest that the episodes of reduced sea-ice cover and corresponding relatively high sea-surface salinity and temperature that are centered at *7500, 5000, and 2000 years BP might correspond to episodes of stronger vertical mixing in the upper water column.

The most significant Arctic warming period during the last century form 1919 to 1939 is not mentioned, and not the influence the permanent input of warm water to the Arctic Basin by the West Spitsbergen Current has , which is presumably one of the most effective force to drive the Arctic climate, and did also the Arctic warming 90 years ago, as explained in detail in the book: “Arctic Heats Up”.



[1] J.L. McKay, A. de Vernal, C. Hillaire-Marcel, C. Not, L. Polyak, and D. Darby; (2008); “Holocene fluctuations in Arctic sea-ice cover: dinocyst-based reconstructions for the eastern Chukchi Sea”, Canadian Journal of Earth Sciences, 45: 1377–1397; http://bprc.osu.edu/geo/publications/mckay_etal_CJES_08.pdf