Category Archives: Sea ice habitat

Fat polar bear of late summer in Arctic Canada

Retired Mountie and bird photographer Clare Kines captured on film one of those ‘canaries of in the coal mine’ of the Canadian Arctic we hear so much about. Kines is from Arctic Bay and took the photo a few weeks ago, on 9 September, on the north end of Baffin Island (just east of where the famous National Geographic ‘starving’ bear was filmed in 2017). His photo was published 14 September by Nunatsiaq News.

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Wrangel Island research team counted a record number of Chukchi Sea polar bears in 2020

Many Chukchi Sea polar bears spend the summer on Wrangel Island and a survey there conducted by Russian researchers in 2020 reportedly collected data on a record 747 bears, well up from the 589 reportedly counted in 2017 by the same team (photo below is from 2015).

Note the latest survey of the Chukchi Sea estimated about 3,000 bears inhabit the region (AC SWG 2018; Regehr et al. 2018), at least 1,000 more that the figure of 2,000 used in recent IUCN assessments and survival predictions (Amstrup et al. 2007; Regehr et al. 2016; Wiig et al. 2015). Wrangel Island is the primary terrestrial denning area in the Chukchi Sea (Garner et al. 1984; Rode et al. 2014) and a recently published study showed that the body condition (i.e. fatness) and litter size of Chukchi Sea polar bears has not been negatively affected by low summer sea ice (Rode et al. 2021).

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Still waiting for two thirds of polar bears worldwide to disappear due to lack of summer sea ice

It’s hard to believe that a polar bear specialist would claim that their predictions have come true, given the facts of the matter: that polar bears arguably number over 30,000 worldwide and regions with the most dramatic sea ice declines have not documented reduced polar bear health or survival. But in mid-July this year, Andrew Derocher – one of the field’s most vocal promoters – did just that: proclaimed on twitter that “virtually all of our predictions are coming true.” Except, none of them did, especially the most widely-promoted one, which failed spectacularly.

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Svalbard polar bear paper falsely assumes that loss of genetic diversity has negative consequences

A new paper published today deals with an animal conservation issue I’ve addressed twice before: the theoretical assumption that loss of genetic diversity must be detrimental to species survival despite there being little evidence that this has been the case in real life. For this new study, the authors carried out some complicated measuring of genetic diversity loss and inbreeding amongst and between Svalbard region polar bear populations between 1995 and 2016 (see map below), and then modelled what this could lead to in 100 generations (1210 years), with the over-anxious hand-wringing we’ve all come to expect from such prophesies. As far as I can see, it’s all meaningless number-crunching without relevance to the real world of polar bears.

To support their claim of harm from loss of genetic diversity, the authors of this paper (Maduna et al. 2021) cite four theoretical papers that assume as fact that loss of genetic diversity is harmful but not the evidence to back up the claim. They apparently never bothered to look at species that have actually suffered dramatic loss of genetic diversity. Northern elephant seals, for example, reduced to 20-30 animals more than 100 years ago, have rebounded to a population of about 170,000 with extremely low genetic diversity but no apparent health or survival repercussions. Similar genetic bottlenecks and recoveries have been documented in Guadalupe fur seals, San Nicolas Island foxes, mouflon sheep, and North Atlantic right whales (among others), which I discussed in detail here (with references). I discussed the issue again in regards to a similar polar bear ‘genetic diversity’ paper in 2016.

Conspicuous by its absence in this new publication is a citation of the recent paper that revealed the body condition of female Svalbard polar bears had increased significantly between 2004 and 2017 despite a pronounced decline in summer and winter sea ice extent (Lippold et al. 2019: 988). Nor did the paper cite data collected by the Norwegian Polar Institute that show the body condition of adult males in Svalbard has not changed since 1993 or that population numbers have not declined. Instead, the authors mention only that reduced numbers of pregnant females have reached traditional denning areas due to lack of ice and that bears have spent less time feeding at glacier fronts than they used to do (Maduna et al. 2021: 2), as if the only polar bear data available in relation to sea ice decline was negative.

Figure 1 from Maduna et al. 2021

Population bottlenecks during the Last Glacial Maximum when suitable habitat was scarce and another in the late 1800s/early 1900s due to wanton overhunting left polar bears with remarkably low genetic diversity but no apparent ill-effects to their overall heath. Oddly, this recent work by Maduna and colleagues assumes without evidence that a bit less genetic diversity could be devastating to Svalbard bears more than 1000 years from now. While the media expectedly promote this as scary new evidence of what climate change has wrought (here and here), I am not impressed.

This is conservation biology done WWF-style: loss of genetic diversity sounds bad to people who don’t know better, but real-world evidence shows it isn’t.

References

Lippold, A., Bourgeon, S., Aars, J., Andersen, M., Polder, A., Lyche, J.L., Bytingsvik, J., Jenssen, B.M., Derocher, A.E., Welker, J.M. and Routti, H. 2019. Temporal trends of persistent organic pollutants in Barents Sea polar bears (Ursus maritimus) in relation to changes in feeding habits and body condition. Environmental Science and Technology 53(2):984-995. https://pubs.acs.org/doi/10.1021/acs.est.8b05416

Maduna, S. N., Aars, J., Fløystad, I., Klütsch, C. F. C., Zeyl Fiskebeck, E. M. L., Wiig, Ø. et al. 2021. Sea ice reduction drives genetic differentiation among Barents Sea polar bears. Proceedings of the Royals Society B  288 (1958): 20211741. https://doi.org/10.1098/rspb.2021.1741 OPEN ACCESS

Abundant Chukchi Sea ice explains silence on walrus haulouts in Alaska and Russia so far

There has been abundant sea ice in the Chukchi Sea this summer: so much so that walrus herds have not found it necessary to use beaches on the Alaskan coast as resting haulouts. Now, in early September, almost the entire northern Chukotka coast is covered in ice, blocking use of those beaches that have been traditionally used in September through November. Wrangel Island (an important denning area for polar bears) is still almost surrounded by ice, which hasn’t happened in decades.

Just two years ago, a big deal was made of the fact that the entire coast of Alaska was ice-free by early August and that walrus herds had come ashore at Point Lay earlier than any year since 2007 – all put down to climate change. Last year, walrus started to come ashore one day earlier than in 2019, on July 29. Although no one has presented any evidence that the walrus are suffering in any way due to using beach haulouts during the ice-free season (MacCracken et al. 2017), the haulouts are still presented as bad news and portends of catastrophe to come.

Inset map above shows the location of Point Lay, Alaska where Pacific walrus haulout during the ice-free season.

This year is a totally different story and of course, the biologists are suddenly silent.

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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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Foxe Basin polar bear attack leaves three people seriously mauled, airlifted to hospital

The attack happened yesterday afternoon (10 August) about 2:30 PM local time near the community of Sanirajak (listed as Hall Beach on ice charts), which is in Foxe Basin, Nunavut (population about 800). There are few details yet on the human victims of the mauling other than that they were two women and a man. All three were badly injured. They are now in hospital and expected to survive.

It appears the bear died as a consequence of the attack but there has been no mention of its condition, age, etc., or the circumstances of the attack. There is no ethical reason for blaming this broad-daylight attack on lack of sea ice (although some will try), since there is abundant ice in the region at the moment, as the charts below show. Expect an update as the story unfolds.

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Tipping points, Attenboroughesque narratives of climate doom and dying polar bears

Outlandish ‘tipping point’ rhetoric is about to be regurgitated once again during the promotion of the latest IPCC report, due today. Tipping points are those theoretical climate thresholds that, when breeched, cause widespread catastrophe; they are mathematical model outputs that depend on many assumptions that may not be plausible or even possible.

Polar bears often get caught up in motivational tales of sea ice tipping points.

Tipping points are not facts: they are scary stories made to sound like science.

This is why Sir David Attenborough has totally embraced the tipping points narrative. He even made a movie fully devoted to them, called, Breaking Boundaries – The Science of Our Planet. Tipping points are the animal tragedy porn of mathematical models and Attenborough has adopted them both.

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Polar bear attack in Greenland gratuitously blamed on recent ‘heat wave’

A polar bear bit the hand of a member of a film crew near the Danish military base of Daneborg in East Greenland on Monday (2 August) and predictably, this has been blamed on recent warm temperatures in the region. There is no specific evidence of cause and effect, of course. The news outlet reporting the incident cites some non-specified ‘experts’ as providing the generic ‘warming makes polar bears starve or behave badly’ excuse that makes no sense in this particular instance.

Here is what the news report had to say (3 Aug), my emphasis:

Early on Monday, while the sun does not set in summer at this latitude, the bear poked his head through a poorly closed window of a research station where the documentary team was staying about 400 metres from the small base of Daneborg.

A Danish Arctic military unit based in Greenland said the bear bit the hand of one of the three male team members before they used warning pistols to force the animal to flee.

Transported first to Daneborg, the injured documentary maker had to be evacuated to Akureyri, a town in Iceland.

Already blamed for five incidents until now, the bear returned again later in the morning and then again overnight Monday to Tuesday when it broke a window of the research station before fleeing.

“The local authorities have from now on categorised the bear as ‘problematic,’ which allows for it to be shot dead, if it returns,” the Danish military unit said.

Daneborg is marked on the map below:

Any bear causing problems in this region would have just come off the ice, since three weeks ago there was plenty of ice available offshore a bit to the north (see chart below for 7 July). Virtually all bears are at their best condition at this time of year, except for young, inexperienced bears or those that are sick or injured. Warm temperatures would not be causing any bear to be desperately looking for food unless it was desperate for some other reason (sick, injured, or an under-nourished young bear). However, nothing is stated in this report about the physical condition of the bear, its approximate age or its sex, even though it has been seen multiple times. Young male bears, for example, are far more likely to become problems near communities than any other age class (Wilder et al. 2017), because these bears have to compete with older, larger bears to keep whatever seals they manage to kill.

Note the reliance on un-named ‘experts’ at the end of the same news report:

Experts say the retreat of the ice pack, the hunting ground of the polar bear, forces them to stay on land more often and they find it harder to find food and sustain a species already considered vulnerable.

Although still rare, the close encounters with humans are increasing as bears more frequently approach inhabited areas in their search for food, environmental protection officers say.

What generic pap! The community has a problem bear on its hands, a situation which northern communities across the Arctic must contend with on a continual basis. Even if there was ice offshore, there would be the possibility of bears coming ashore and causing problems.

There is also the issue no one wants to talk about because it has nothing to do with declining sea ice: with more bears comes more problem bears.

References

Wilder, J.M., Vongraven, D., Atwood, T., Hansen, B., Jessen, A., Kochnev, A., York, G., Vallender, R., Hedman, D. and Gibbons, M. 2017. Polar bear attacks on humans: implications of a changing climate. Wildlife Society Bulletin, in press. DOI: 10.1002/wsb.783 http://onlinelibrary.wiley.com/doi/10.1002/wsb.783/full

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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