Tag Archives: Northwest Passage

Polar bear habitat update at mid-August

Oddly, after light winter ice coverage on Canada’s east coast and a slightly earlier sea ice breakup on Hudson Bay, the Arctic melt season has stalled. That’s not my opinion but the observation of the sea ice experts at the National Snow and Ice Data Center (NSIDC):

Sea ice loss during the first half of August stalled, though ice in the Beaufort Sea is finally starting to weaken. The Northern Sea Route appears closed off in 2021, despite being open each summer since 2008.

Overall, ice coverage is well above what it was in 2012 (the lowest September extent since 1979) and many years since:

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Sea ice melt in the Arctic Basin leaves an area for polar bears larger than Greenland

Most polar bears that spend the spring feeding in the peripheral seas of the Arctic Basin (such as the Beaufort, Chukchi, Kara, and Barents Seas) remain on the persistent pack ice of the central Arctic during the summer and this August, that refugium is still larger than Greenland. Most of these bears do not use this July-September Arctic Basin ice as a hunting platform unless they are very lucky: the few seals available are hard to catch. For the most part, polar bears fast or eat very little during the summer whether they are on land or on ice (see references in this post).

Svalbard polar bear fall 2015_Aars

Since early June, sea ice experts have been wringing their hands over the melting of Arctic sea ice and offering breathless speculation that this year’s September minimum could be – gasp! – as low as or less than 2012 or even less. But now, as the graph of ice cover at 28 August shows below, that outcome is looking not just unlikely but virtually impossible (the blue line is 2019 extent, red dashed line is 2012, and the brown line is 2016):

Sea ice extent 2012 and 2016 vs 2019 with 2x deviation at 28 Aug_NSIDC interactive

As expected, the failure of the ice to remain on track to set a new record September low due to global warming is shrugged off with a reminder that summer ice extent “is sensitive to changes in daily weather conditions.”

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Experts’ vision of an ice-free summer is already wrong & benefitting polar bears

Polar bear populations in most of the Canadian Arctic Archipelago (CAA) must be booming, as they are elsewhere. That’s because the ‘experts’ were even more wrong in their predictions of future sea ice conditions than most people realize: they expected the CAA would remain choked with ice during a ‘nearly ice-free’ summer driven by human-caused global warming.


Wang and Overland 2012 fig 3b marked

Map presented by Wang and Overland (2012: Fig 3) shows what these experts thought a ‘nearly ice-free’ summer would look like, which they expected to occur by 2030 or so.

Look at the map from Wang and Overland (2012) above, which is what they thought a ‘nearly ice-free’ summer would look like in the year 2030 or so.

Wang and Overland used the same models used by USGS biologists to predict the future survival of polar bears based on habitat loss (Amstrup et al. 2007; Atwood et al. 2016; Durner et al. 2007, 2009). Note the thick ice in the CAA — what USGS experts call the ‘Archipelago’ sea ice ecoregion (denoted by white in the map), indicating ice about 1 metre thick (2-3 feet) — expected to remain at the height of summer in 2030.

[Earlier renditions of sea ice projections (e.g. ACIA 2005) show something similar. The second update of the ACIA released just yesterday (AMAP 2017, described here by the CBC) has prudently included no such firm predictions in their Summary for Policy Makers, just dire warnings of future catastrophe. But see the 2012 update.]


The problem is that ice in this region has been largely absent most summers since 2006, even though overall ice extent has been much more extensive than expected for a ‘nearly ice-free’ summer, as I show below.

This is not another “worse than we thought” moment (Amstrup et al. 2007) — this is sea ice models so wrong as to be useless: failed models used to inform future polar bear survival models that got the bears declared ‘threatened’ with extinction in the US in 2008 (Crockford 2017).

It also means polar bears are almost certainly doing much better than recent population counts indicate, since only one subpopulation out of the six in the CAA has recently been assessed. But since polar bear specialists have consistently underestimated the adaptability of this species and the resilience of the Arctic ecosystem to respond to changing conditions, it’s hard to take any of their hyperbole about the future of polar bears seriously. Continue reading

M’Clintock polar bear survey’s first year plagued by fog in an area thick with heavy ice

“Blizzards, we had fog — we had to sleep in the helicopter, on the sea ice one night, because we couldn’t fly anywhere,” Markus Dyck, senior polar bear biologist with the GN, told Nunatsiaq News Sept. 5.”

Polar bear with dart_bear_570_2012 Kane Basin_M Dyck photo

Fog was the theme of polar bear research this summer in Queen Maud Gulf, otherwise known as the M’Clintock Channel polar bear subpopulation region.

The ice has been heavy in that region as well, according to a the National Snow and Ice Data Center (NSIDC) and reported yesterday in another story (Heavy pack ice in NW Passage ice creates tough conditions this year: Pack ice clogs Queen Maud Gulf).

For maps showing where M’Clintock Channel and Queen Maud Gulf actually are, see the maps — and more quotes — below.
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Lancaster Sound – a rarely-mentioned region with a large polar bear population

The polar bear subpopulation designated as Lancaster Sound lies at the eastern entrance to the Northwest Passage in the Canadian High Arctic (Fig.1). We rarely hear about it but this region has one of the largest polar bear populations anywhere in the Arctic – only the Barents Sea and Foxe Basin have higher estimated population sizes.

Figure 1. Lancaster Sound, magenta. Map courtesy Polar Bear Specialist Group, additional labels added.

Figure 1. Polar bear subpopulations with Lancaster Sound marked. Map courtesy IUCN Polar Bear Specialist Group, additional labels added.

Lancaster Sound includes the communities of Arctic Bay on northwestern Baffin Island and Resolute Bay on Cornwallis Island. Devon Island, which lies on the northern boundary, has no permanent communities, although two research stations are present (see here and here). A more detailed map showing the exact boundaries is available in Vongraven and Peacock (2011).

The eastern portion of Lancaster Sound is generally clear of ice by late summer (hence the Northwest Passage) but the western third of the region not only retains pack ice later in the season but some multiyear ice remains throughout the year.

The proximity of Lancaster Sound to Baffin Bay and the eastern Northwest Passage (Fig.2) undoubtedly exposed polar bears there to hunting by European whalers during the 1800s and early 1900s (see previous post here, especially Fig. 5), from which the population appears to have recovered.

On the other hand, the proximity of Lancaster Sound to oil and gas reserves further north in the High Arctic generated much-needed funds for polar bear biologists in the mid-to-late 1970s to collect essential baseline data for the entire region (Schweinsburg et al. 1982; Stirling et al. 1979, 1984; Stirling and Latour 1978).

Figure 2. The main Northwest Passage route starts at Lancaster Sound and runs east through Parry Channel because these waterways routinely clear of ice in late summer. The approximate boundary of the Lancaster Sound polar bear subpopulation (area ~490,000 km2) is marked in yellow; POW is Prince of Wales Island. Map from Wikipedia, labels added.

Figure 2. The main Northwest Passage route starts at Lancaster Sound and runs east through Parry Channel because these waterways routinely clear of ice in late summer. The approximate boundary of the Lancaster Sound polar bear subpopulation is marked in yellow; POW is Prince of Wales Island. Map from Wikipedia, labels added. Click to enlarge.

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