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Aerial view of the edge of the sea ice in Nunavut, Canada. Credit: Doc Searls via Wikimedia Commons .

Credit: National Snow and Ice Data Center.

Ice age data this year show that the ice cover remains much thinner than it was in the past, with a high proportion of first-year ice, which is thin and vulnerable to summer melt. After the record low minimum of 2007 the Arctic lost a significant amount of older, thicker ice, both from melting and from movement of ice out of the Arctic the following winter. In the last few years, the melt and export of old ice was less extreme than in 2007 and 2008, and multiyear ice started to re-grow, with second and third-year ice increasing over the last three years.

Arctic sea ice. Credit: Pink floyd88 a via Wikimedia Commons.

   

Credit: National Snow and Ice Data Center courtesy J. Maslanik and M. Tschudi, University of Colorado.

  
In the map above you can see how much of 2012's winter sea ice was new ice—just formed this year (purple). And how there's virtually nothing left of the old sea ice that was born five or more years ago (white).
  

Credit: National Snow and Ice Data Center courtesy J. Maslanik and M. Tschudi, University of Colorado.

  
The graph above shows the trend since 1983... how much old ice there used to be and what an endangered species it is now.

Bowhead whale. Via.

It is not known what attracted the whales to this area, given the region has relatively low marine production in autumn compared with other known bowhead whale feeding areas.

Bowhead whale bones on ceremonial ground, Point Hope, Alaska. Credit: rnoblin via Flickr.

During the commercial whaling period (i.e. pre-1900), several harpoon heads of Atlantic origin were discovered in bowhead whales harvested in the Chukchi Sea/western Arctic, but this information was largely dismissed as anecdotal by scientists. 

Recent genetic studies compared DNA of whales from Foxe Basin, Canada to whales from Alaska and suggest genetic mixing, although results are based on a small sample size from a highly segregated population. The lack of genetic differentiation between whales in the Pacific and the Atlantic, acknowledging that samples are taken several thousand years apart, suggests that some exchange of individuals occurred between whales in Svalbard and Alaska. 

Credit: Mads Peter Heide-Jørgensen, et al. Biol Lett. DOI:100.1098/rsbl.2011.0731.

The Northwest Passage with tracks of four bowhead whales and extent of sea ice with greater than 50% concentration (white fields). (a) Track of a whale tagged on 4 May 2002 in West Greenland and ice extent on 20 September 2002. (b) Track of a whale tagged in Alaska on 12 May 2006 and sea ice extent on 8 August 2006. (c) Track of a whale tagged on 24 May 2010 in Alaska, one tagged on 15 April 2010 in West Greenland, and sea ice extent on 14 September 2010. The insert shows the area where whales occurred together in 2010. The whale from Alaska was present in Viscount Melville Sound between 19 August and 18 September while the whale from Greenland was present from 11 to 28 September.

1980: Sea ice coverage 1 Nov-31 Jan. Credit: NASA Earth Observatory.

2012: Sea ice coverage 1 Nov-31 Jan. Red star marks approximately where the two whales met in 2010. Credit: NASA Earth Observatory.

Given recent rates of sea ice loss, climate change may eliminate geographical divisions between stocks of bowhead whales and open new areas that have not been inhabited by bowhead whales for millennia (e.g. North of Greenland and north of the Canadian Archipelago).

The documented movements of bowhead whales in the Northwest Passage are perhaps an early sign that other marine organisms have begun exchanges between the Pacific and the Atlantic Oceans across the Arctic. Some of these exchanges may be harder to detect than bowhead whales, but the ecological impacts could be more significant should the ice-free Arctic become a dispersal corridor between the two oceans.

• Mads Peter Heide-Jørgensen, Kristin L. Laidre, Lori T. Quakenbush, and John J. Citta. The Northwest Passage opens for bowhead whales. Biol Lett. DOI:10.1098/rsbl.2011.0731.

Bear Glacier, Alaska. Via.

Glacier melt tunnel. Credit: Dook Cook | DougAK via Flickr.

• About a quarter of the average annual ice loss came from glaciers and ice caps outside of Greenland and Antarctica (roughly 148 billion tons, or 39 cubic miles). 
• Ice loss from Greenland and Antarctica and their peripheral ice caps and glaciers averaged 385 billion tons (100 cubic miles) a year.

Glacier Bay, Alaska. Credit: NPS.

"This study finds that the world's small glaciers and ice caps in places like Alaska, South America and the Himalayas contribute about 0.02 inches per year to sea level rise," said Tom Wagner, cryosphere program scientist at NASA Headquarters in Washington. "While this is lower than previous estimates, it confirms that ice is being lost from around the globe, with just a few areas in precarious balance. The results sharpen our view of land-ice melting, which poses the biggest, most threatening factor in future sea level rise." 

Bering Glacier, Alaska. Credit: NASA.

• Thomas Jacob, John Wahr, W. Tad Pfeffer & Sean Swenson. Recent contributions of glaciers and ice caps to sea level rise. Nature. DOI:10.1038/nature10847

As the supply ship, the Hansa followed the Germania [exploration ship] until July 19, when [Captain Paul Friedrich August] Hegemann misread a flag signal by [captain of the Germania, Carl] Koldeway and went ahead; the ship disappeared in the fog and got separated. The agreement was to meet in such a situation at Sabine Island. After unsuccessful attempts to get there, Hansa was inescapably stuck in the pack ice by mid-September 1869. During the next month, the ship was slowly milled by the ice and finally sank on October 22 at a position 70°32’N, 21°W approximately 10 km from the East Greenland coast. The crew managed to survive the winter in a shelter built of coal dust briquettes, while drifting on the sea ice southward along the eastern coast of Greenland. In June 1870, the crew got to the coast by boat and reached the Moravian Herrnhut mission at Narsaq Kujalleq (then Frederiksdal/Friedrichsthal) near Cape Farewell, from where they got back to Germany on a Danish ship.