Tag Archives: breakup

Polar bear habitat update for end July 2021 compared to previous years

Here’s a trip down memory lane for Arctic sea ice at the end of July, which as far as I can see provides no evidence that a very low sea ice disaster is in the cards for polar bears this year.

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Western Hudson Bay polar bears: still some out on the sea ice, some causing trouble

As of Monday (19 July), more polar bears had come ashore near Churchill and on the shores of Wakusp National Park but some are still out on the bay. The pattern of ice breakup this year means most bears will come ashore well south of Churchill and make their way north over the summer and fall. There have been two Churchill ‘problem’ bear reports so far but not one for this week, so I’ll go ahead and post without it.

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Polar bears of western Hudson Bay still on the ice at third week June

According to the tracker map provided by Andrew Derocher (University of Alberta), all of the western Hudson Bay polar bear females that still have operational satellite collars (deployed in 2019) are still out on the ice of Hudson Bay. The Explore.org live video cam that sits on the shore of Wapusk National Park just south of Churchill has been capturing images of caribou and birds but so far, no polar bears. Last year, the first bear seen onshore by the cameras (shown in the video) was on 13 July.

It wasn’t until a month later that more bears were seen: the fat mother and cub in the screencap below were spotted on 18 July 2020 and the last of the collared bears didn’t come ashore until late August:

This year at 21 June, only 6 collars still operating but only one of them is anywhere close to shore yet (courtesy Andrew Derocher via twitter, below):

That ice in the middle of the bay is still primarily very thick first year ice, as the chart for this third week of June shows (below):

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Polar bear habitat update and the progress of breakup on Hudson Bay

At mid-month, there is still an abundance of thick first year ice over much of Hudson Bay, suggesting that – yet again – this will not be an early breakup year for Western Hudson Bay polar bears. The early breakup years in the past (like 2010) that generated all kinds of panic amongst polar bear specialists have not developed into ever-continuing declining trend (Lunn et al. 2016) or another abrupt step-change like there was in 1998/99 (Castro de la Guardia et al. 2017).

In the last few years conditions have been more like they were in the 1980s than the prophesied catastrophe we were promised. I don’t see a ‘tipping point’ for Hudson Bay; do you see a tipping point?

The more light green areas of thinner ice present, as there was in 2010 (below), the earlier breakup is apt to be:

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Polar bear habitat in Canada at the first week of June sees widening of critical polynyas

Winds primarily cause the apparent sea ice ‘breakup’ in late spring through the widening of persistent polynyas and shore leads. This year the development of critical open water areas in Canada (which are important feeding areas for polar bears) is on track with previous years in most areas, although there is a lot of year-to-year variability.

Several prominent polynas also opened up along the Russian coast and Northeast Greenland: see the entire Arctic condition at 7 June 2021 below, courtesy NSIDC:

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Western & Southern Hudson Bay polar bears experience earliest freeze-up in decades

This is shaping up to be one of the shortest ice-free seasons in at least 20 years for both Western and Southern Hudson Bay polar bears.

Hudson Bay sea ice at 2 November 2020. NSIDC Masie chart.

Last week, sea ice started forming along the shore of Hudson Bay, from the north end all the way south into James Bay. So far, the shorefast ice that’s forming is only a narrow strip along the coast but is thickening and becoming broader each day, which means that unless something changes dramatically, the bears should all be on the ice at the end of the week, an exodus from shore that hasn’t happened this early in WH since 1993 (the earliest since 1979).

The last WH tagged polar bear didn’t leave the ice this year until 21 August, which means if it’s on the ice by the end of this week it will have spent only 11 weeks onshore – less than 3 months. Even the first bears that came ashore in mid-July will have only spent about 16 weeks on land – at least a month less than they did a decade ago (Stirling and Derocher 2012). Four months spent ashore was the historical average for Western Hudson Bay bears in the 1970s and 1980s (Stirling et al. 1977, 1999). This year, most polar bears will have spent only about 13-14 weeks on land because they did not come ashore until early August.

UPDATE 8 November 2020: Report from Churchill area polar bear guide Kelsey Eliasson, via Facebook Saturday 7 November: “Most bears have left on the ice – including peanut – but still some stragglers” [Peanut’ is a well-known female who has two cubs this year]. See below for sea ice chart for 8 November shows broadening band of grey ice clearly thick enough to support the weight of adult bears (and the same thing is happening in Southern Hudson Bay):

Hudson Bay North daily stage of development 2020 Nov 8_all grey ice

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Polar bear research on hold in Western Hudson Bay due to COVID-19 restrictions

After spring polar bear research was cancelled in Western Hudson Bay (and pretty much everywhere else) this year because of Covid 19 concerns, it now transpires that fall research is out as well. Travel restrictions implemented by government departments and university administrations (not the health department) apparently mean fall programs to assess the health and status of polar bears in Western Hudson Bay have been put on hold.

Triplet litter of polar bear cubs spotted in Wakusp National Park, Western Hudson Bay. 23 October 2020. Courtesy Explore.org.

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Potential impact of the second-lowest sea ice minimum since 1979 on polar bear survival

The annual summer sea ice minimum in the Arctic has been reached and while the precise extent has not yet been officially determined, it’s clear this will be the ‘second lowest’ minimum (after 2012) since 1979. However, as there is no evidence that polar bears were harmed by the 2012 ‘lowest’ summer sea ice this year’s ‘second-lowest’ is unlikely to have any negative effect.

This is not surprising since even 2nd lowest leaves summer ice coverage in the Arctic at the level sea ice experts wrongly predicted in 2005 wouldn’t be seen until 2050 (ACIA 2005; Amstrup et al. 2007; Wang and Overland 2012) and this is the same amount of summer sea ice that polar bear experts incorrectly predicted would cause 2/3 of all polar bears to disappear. My book explains how it all went wrong: The Polar Bear Catastrophe That Never Happened

In this summary of how polar bears have been doing since the the lowest sea ice minimum in 2012, I show that contrary to all predictions, polar bears have been thriving despite reduced summer ice in the Barents, Chukchi and Southern Beaufort Seas, and because of unexpectedly short ice-free seasons in Hudson Bay and less multiyear ice in the Canadian Arctic Archipelago.

UPDATE 21 September (10:20 PT): NSIDC has just announced the Arctic sea ice extent minimum (preliminary) for 2020 at 3.74 mkm2 reached on 15 September. See full report here.

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First polar bear alert report for Churchill an astonishing seven weeks later than last year

The first report of the Polar Bear Alert Program in Churchill, Manitoba was released today (1 September), a full seven weeks later than last year due to many bears remaining on the Western Hudson Bay ice much later than they have done in the past.

2020 Aug 31 - Polar Bear Stats_week 1 jpeg

As I mentioned previously, as long as I’ve been collecting these published reports (2015), there has not been a first report of the season issued later than the second week in July, so this year is really unusual and I suspect similar to the 1980s.

I thought it possible that this was a Covid-related delay getting conservation officers to Churchill but as you’ll see above, that appears not to be the case: there simply have been not enough serious problems with bears in Churchill to warrant sending officers out before last week. No information on the general condition of bears was included this year, as it has been in other years (see below).  Activity this last week in August 2020 was similar to the first week in July 2018.

Polar bear Cape East 0 Wakusp NP _24 Aug 2020 earlier

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Amid crying over low Arctic ice, W Hudson Bay polar bears leave ice as late as 2009

This year, the last collared Western Hudson Bay polar bear to leave the ice left as late, or later, than the last collared bear did in 2009 (which was an unusually late breakup year) and so far, all bears spotted have been in good physical condition despite inhabiting one of the most southern regions of the Arctic. All the while, sea ice experts have been hand-wringing about low Arctic sea ice –– in general and as polar bear habitat.

Polar bear Cape East 0 Wakusp NP _24 Aug 2020 earlier

A female with two yearling cubs on the shore of Wakusp National Park, Western Hudson Bay on 24 August 2020. Taken via livecam from almost a mile away.

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