Reposted from Dr. Susan Crockford’s Polar Bear Science

By Susan Crockford,

Posted on October 15, 2021 | Comments Offon No signs of a climate emergency for W. Hudson Bay polar bears this year ahead of UN climate meeting

I’ve been told that another complete aerial survey of the Western Hudson Bay polar bear subpopulation (from the Nunavut to Ontario boundaries) was conducted in August this year and that the bears have been hanging out further south than usual. It will be years before the results of the population count are published, of course (especially if it’s good news) but my contacts also say virtually all of the bears are in great condition again this year.

This is significant because W. Hudson Bay bears are one of the most southern subpopulations in the Arctic (only Southern HB bears live further south) and older data from this region is being used to predict the future for the entire global population based on implausible model projections (Molnar et al. 2020). And scary predictions of future polar bear survival are often taken to be proxies for future human disasters (see ‘Polar bears live on the edge of the climate change crisis‘), a point that some activists will no doubt make in the coming weeks, as the long-awaited UN climate change bash #26 (COP26) gets underway in Glasgow, Scotland on October 31.

Condition and Locations of WH polar bears

Rumour has it that most WH bears must have came off the ice east of the Manitoba-Ontario border, as fewer than usual have been spotted north of there (see ‘Zone A2’ on map below). Fifty to sixty very fat bears have apparently taken up temporary residence along the southern coast of Wapusk National Park (around the Owl/Broad River area), where in other years they might have been closer to Cape Churchill. In addition, where in other years there would have been many bears around York Factory and Kaskatama (around Cape Tatum), this year there were none until mid-October.

There are a few bears around Churchill and Cape Churchill, of course (and the Tundra Buggy tours are out scouting for them) but reports of problem bears in town have so far been lower than usual and the webcam at Cape Churchill have been picking up only a few single bears and families of sows and cubs hanging around. See the screencap below taken from one of the Explore.org webcams 9 October 2021.

By the way, I’ve also heard that the dozens of bears that have become proficient at hunting beluga from intertidal boulders in the shallows of the Seal River estuary (north of Churchill) from July to mid-September were back honing their skills this year. Although they would have had to have come off the ice in early-to-mid June this year, they have learned there is a reliable food source at this location where even sows with cubs are able to feast for a couple of months (i.e. it’s not just big male bears that are hunting the small whales). Photo below by Quent Plett, from this 25 January 2020 Churchill Wild blog post.

That certainly fits with the pattern of sea ice breakup this year, which saw the ice pull away from the sector north of Churchill by the end of June (see chart below). Bears committed to spending the summer near Churchill or along the coast of Wapusk National Park to the south must have come off the ice around that time:

The ice mass on the bay broke up rapidly after the end of June.

Remnant ice that persisted along the southwest coast this year left WH bears the opportunity to come ashore along the Ontario coast in mid-to-late July:

Even Southern Hudson Bay bears would have had to come ashore along the Ontario coast in mid-to-late July, weeks earlier than last year:

Rumour also has it that the bears on shore are so fat they have only recently started their traditional migration west and north towards Cape Churchill where sea ice usually forms earliest in the fall.

Most of these bears may be waiting for colder weather to start the trek north: fat bears overheat quickly. However, it is also possible they are in such good shape they know they can wait for the ice to reach them, even if they are further south than usual.

Last year, for example, ice was present from north to south along the entire west coast of Hudson Bay from Foxe Basin to James Bay by the beginning of November, giving Southern Hudson Bay bears much earlier-than-usual access to the newly-formed ice and the critical fall seal hunting opportunities that presented (see chart below for 4 November 2020):

It’s still too early to tell what the Hudson Bay freeze-up pattern will be this year but since most of the bears appear to be in good condition, they should be able to deal with even a late freeze-up if necessary. In other words, it’s looking like yet another great year for Western Hudson Bay polar bears – the 7th in a row by my calculations – despite the gloomy prophesies of the experts.

References

Molnár, P.K., Bitz, C.M., Holland, M.M., Kay, J.E., Penk, S.R. and Amstrup, S.C. 2020. Fasting season length sets temporal limits for global polar bear persistence. Nature Climate Change.  https://doi.org/10.1038/s41558-020-0818-9

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October 17, 2021