The Arctic ice melting season 2010 has ended.
What next?
Posted 29. September 2010

What is the Arctic sea ice going to do in winter 2010/2011, which restarted to grow since the 19^th September. Three months ago the ice extend was the lowest ever, breaking the low record of the year 2007. But that lasted only for about five weeks, from end of May to about 1^st July. From thereon the sea ice increased – statistically – surpassing the low levels of the years 2007 and 2008. After having reached a low point on September 10, the trend reversed for three days, but then began a second decline until September 19. The turning point was unusual sharp and the rise during the last 10 days steep. The Figure (dated 26.Sept) and more details from NSIDIC[1] .

  What next? Presumably no one can make a reliable prediction. The most it can be expected that it seems that the year 2007 marked a record and that there is a trend for slightly more sea ice over the last three years. The sea ice developments over the next six sun-less months is presumably considerably controlled by the internal conditions of the Artic ocean and the adjacent open sea areas. For most Arctic marine waters, temperatures range around -1.5^o C to -1.8^o C. However, summer inflows from the North Atlantic Current and the Pacific Ocean heat waters in the Norwegian, Barents and Chukchi seas to as high as 8^o C to 12^o C, making them the warmest in the region. Although the heat stored during the summer is now quickly released, any sea ice free sea area will continue to pump heat into the atmosphere until it freezes. The matter is largely complicated by the permanent change of the degree of the water salinity that fluctuate with the melting and freezing of the sea ice, but in general, the Arctic Ocean has the lowest salinity of the world’s oceans. (More at: The Arctic-Ru).

 There can hardly any doubt that one can learn a lot from the past. Modern arctic climatologists seems not to be fully aware of that. In a recent book “How Spitsbergen Heats the World” (2008), the reason for the warming of the Arctic that occurred 90 years ago, and lasted for two decades until winter 1939/40 is discussed in great detail, with the conclusion that shift in the most northern extended arm of the Atlantic Gulf Current (West Spitsbergen Current) caused the Arctic to warm since winter 1918/19. The winter temperatures at Spitsbergen  (Fig) indicate the tremendous change, with an increase of plus 8°C over the Jan/Feb. months from one winter (1917/18) to the next (1918/19). This could only by achieved by the book through a thorough analysis of the available air temperature data.

 Less helpful are older sea ice cover information. During the first half of the last century the information about the exact ice cover were extreme rare, and the material available today (see Fig. 4; souce: uiuc.edu) are estimates with considerable uncertainty margins. Only since the sea ice extent is measured by satellites the data draw a good picture of the situation, which actually could mean, that some of the variability is due to permanent observation, while a downward trend since the 1980, whereby the most remarkable change is related to the summer season, a decreasing trend  already since the 1950s. Also summer 2010 remained on this track by the record low ice cover in June. Although meanwhile the increase is significant, the game is wide open.

 What will the ice cover be during winter 2010/11?