South Beaufort Sea polar bear habitat during the Summer Solstice is above average – Rising up because of that?
Dr. Susan Crockford
Sea ice is much higher than recent levels for this time of year in South Beaufort, and only time will tell if that’s bad news for polar bears. Seals need the open water that early summer polynyas provide for feeding, and some polar bears take advantage of hunting opportunities (Stirling and Cleator 1981; Stirling et al. 1981).
It’s been a decade since there was this little open water in early summer in the western US Arctic, especially South Beaufort. It looks like there won’t be widespread open water until July, which could lead to fewer bears on shore in early summer. Recall that in July 2019, NOAA employees Count 31 healthy, fat bears on the shore along the Alaskan coast.
Past and Current condition
Polynya Cape Bathurst in the Beaufort East Sea west of Banks Island was often prominent in May during the late 1970s (image below from Smith and Rigby 1981):
As you can see, this polynya was in the classic lineup on May 15 of this year:
However, at the beginning of June, it was almost completely frozen again:
Now, on the first day of summer, the polynya is just starting to reopen, and the ice surrounding it is a thick multi-year (brown) and >1.2m (green) dark):
The chart below shows more ice than usual in East Beaufort (in blue):
The classic CIS chart shows what this looks like in ice cover versus open water:
Compare the chart above for this year (above) with previous years (below).
On the same day going back in time shows how unusual the situation is: no open water since 2013.
Presenter
Stirling, I. and Cleator, H. (eds). In 1981. Polynyas in the Canadian Arctic. Canadian Wildlife Service, Occasional Newspaper No. 45. Ottawa.
Smith, M. and Rigby, B. 1981. Distribution of polynyas in the Canadian Arctic. In: Polynyas in the Canadian Arctic, Stirling, I. and Cleator, H. (eds), pg. 7-28. Canadian Wildlife Service, Occasional Newspaper No. 45. Ottawa.
Stirling, I, Cleator, H. and Smith, TG 1981. Marine mammals. In: Polynyas in the Canadian Arctic, Stirling, I. and Cleator, H. (eds), pg. 45-58. Canadian Wildlife Service, Occasional Newspaper No. 45. Ottawa. Pdf of appropriate excerpts of the above papers here.
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