Tag Archives: breakup

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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Few bears on the ice off Western Hudson Bay at 14 August but will be onshore soon

Polar bear biologist Andrew Derocher published a tracking map of his collared polar bear females that shows one bear (out of 11) still on the rapidly diminishing ice north of Churchill in Western Hudson Bay – and where there is a collared female, there is almost certainly other bears doing the exact same thing:

Derocher 2020 WHB tracking map 14 Aug_1 bear still on the ice

Without evidence to support such a claim, Derocher (below) assumes this collared female is probably hunting seals. In fact, last year he admitted that most bears on Hudson Bay from at least July onward are unlikely to be successfully hunting seals:

Derocher 2020 Aug 14_1 bear still on the ice at 14 Aug odd behaviour

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Many W Hudson Bay polar bears still offshore at 7 August despite apparent low ice levels

Contrary to all expert expectations, five female polar bears (45%) out of eleven that had tracking collars attached last year were still out on the sea ice that’s lingering along the western shore of Hudson Bay as of 7 August. And if five collared bears are out there, then there are almost certainly many more without collars doing the same thing. This pattern of bears staying out on the ice long after the so-called ‘critical threshold’ of 50% concentration has passed has been going on since at least 2015 and many bears on tracking maps in July and August appear to be on ice that doesn’t exist.

Chukchi Sea polar bear Arctic_early August 2018_A Khan NSIDC small

There are two explanations for this pattern and both are likely true: 1) much more ice actually exists on Hudson Bay than satellites can detect and 2) polar bear experts are wrong that Western Hudson Bay polar bears head to land soon after sea ice concentration drops below 50%. Models that predict a catastrophic future for Western Hudson Bay polar bears (Castro de la Guardia et al. 2013; Molnar et al. 2020) assume that ice coverage of less than 50% in summer greatly reduces polar bear survival. However, if polar bears do not always head to land when sea ice drops below 50% then the models cannot possibly describe their future accurately. In other words, depending on the discredited ‘worst case’ RCP8.5 climate scenario for the most recent polar bear survival model that extrapolates from Western Hudson Bay bear data to many other subpopulations, as I discussed previously, may not be its only fault.

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Six good years in a row for the polar bear subpopulation used to predict species demise

In something resembling a new pattern for Western Hudson Bay polar bears, most of the animals are still out on the ice in late July this year, just like they were in the 1980s. The same thing happened last year but was brushed off as a happy anomaly. However, after last fall’s 1980s-like early freeze-up, this makes the sixth year in a row of good to very good sea ice conditions for Western Hudson Bay polar bears. No wonder polar bear experts haven’t published these data: good sea ice conditions along with polar bears coming ashore fat and healthy are not just inconvenient – they threaten to destroy the extinction panic narrative that depends on Western Hudson Bay bears showing evidence of harm from reduced sea ice.

WH 18 Sat July 2020 noon PT Cape East fat mother and cub_Wakusp NP explore dot org livecam

Fat mother and cub onshore at Wakusp National Park, Western Hudson Bay 18 July 2020, one of the first of the season.

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Hudson Bay sea ice cover at early summer 2020 is similar to the 1980s

Don’t expect to hear this news from polar bear activists busy promoting the supposed threat to polar bears from declining Arctic sea ice but ice cover over Hudson Bay so far this summer has been very similar to what it was in the 1980s – often promoted as ‘the good old days’ for Western Hudson Bay polar bears. As of the end of June 2020, very concentrated ice (9/10-10/10) more than 1 metre thick still covered most of the bay and there was still no open water near Churchill along the west coast down into James Bay.

Hudson Bay weekly concentration 2020 June 29 PNG

Polar bear activists don’t like to have current Hudson Bay sea ice reality ruin their social and news media narrative that ‘polar bears are all gonna die’, so they instead emphasize the obsolete ‘declining trend’ for Western Hudson Bay breakup dates that haven’t been updated since 2015 (e.g. Castro de la Guardia et al. 2017; Lunn et al. 2016). They do this despite the fact their colleagues admit polar bears don’t catch many seals after late June (regardless of sea ice conditions) because it is past the peak spring feeding period (Obbard et al. 2016; Lippold et al. 2019). Like in the 1980s, in 2015 and 2019 some bears stayed on the ice until early August and 2020 is shaping up to be another 1980’s-like summer.

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Polar bear habitat in Canada and eastern Alaska compared at end of June 2012-2020

Here is a quick compare and contrast of sea ice habitat for polar bears in Canada and the Southern Beaufort region of eastern Alaska near the end of June, 2012-2020.

Baffin Island Bylot Sound bear_smaller_shutterstock_1144169858

Similarities between Hudson Bay ice/open water in the sea ice charts below are striking. Ice cover at the end of June shown in these charts since 2012 reinforces the fact, documented in the peer-reviewed literature, that there has been no continued declining trend in dates of sea ice breakup for Western and Southern Hudson Bay since 1998 at least (Castro de la Guardia et al. 2017; Lunn et al. 2016). WH bears are still on the ice.

As a consequence, recent declarations of impending doom for Hudson Bay polar bears, based on claims of reduced population size and health of these subpopulations – which in any case are statistically insignificant for WH and SH (Obbard et al. 2018; Dyck et al. 2017) – must be due to some other cause (Crockford 2020).

In all areas, winds rather than melt due to increased temperatures drive much of the expansion of open water at this time of year.

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