Wednesday, December 14, 2022

"Polar bear habitat update: Winter conditions well on their way across the Arctic except in Svalbard"

From Polar Bear Science, December 11:

December is late fall in the Arctic: winter conditions are gearing up but are not in full swing everywhere. Sea ice is developing quickly over Hudson Bay and moving slowly towards the Bering Sea but the Svalbard archipelago is still devoid of pack ice.

Such conditions north of Norway have existed most years since 2005: it’s certainly not a new development for Svalbard to be free of surrounding pack ice in December (although there was lots of ice in 2019 and 2021 by late November). This means traditional denning areas on the eastern islands again cannot be used by pregnant polar bear females, because they must be ensconced in their dens by at least late November or so.

Some seem to think this is a calamity: that such ‘loss of habitat’ is a huge concern for the survival of the subpopulation, if not the entire species. However, the same conditions existed in 2011 and did not result in a dramatic decline in the population as measured in 2015 (Aars et al. 2017) because the bears knew how to respond. They have apparently moved north to make maternity dens on the sea ice or east to the Franz Josef Land archipelago in Russia (Aars 2015). These areas are still within the Barents Sea subpopulation boundaries and researchers have known for two decades that bears have moved around within it (Andersen et al. 2012; Derocher 2005; Maurizen et al. 2002).

Sea ice update

Note that for the last few weeks, the Canadian Ice Service charts for most of Hudson Bay ice have only been updating once a week (on Wednesday). This seems to be a perennial problem about this time of year. It may have something to do with glitches in the satellite data, although they offer no explanation for the issue. 

Svalbard ice conditions....

....MUCH MORE