Category Archives: Life History

Arctic sea ice habitat for polar bears is like a big pond that dries up partially in summer

What’s a good analogy for sea ice as essential polar bear habitat? Biologist Andrew Derocher claims that the soil in a forest is appropriate, because without the soil you can’t have the forest ecosystem. However, that’s a specious comparison because the amount of soil in a forest does not change markedly with the seasons the way that Arctic sea ice does.

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A much better analogy is a big pond that dries up a bit every summer. The amount of habitat available to sustain aquatic plants, amphibians and insects is reduced in the dry season but many species have special adaptations for surviving reduced water availability. For the rest of the year, however, the pond provides an abundant and non-limiting habitat for all the creatures and plants that live there.

Beaver pond USFWS

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New ice on Hudson Bay a week earlier than 2017: another early freeze-up ahead?

Last year, an early freeze-up of Western Hudson Bay sea ice almost ruined the Polar Bear Week campaign devised by Polar Bears International to drum up donation dollars and public sympathy for polar bear conservation. Many bears were on the ice hunting by 7-8 November in 2017 before the celebratory week was done (the average date that bears left the ice in the 1980s): sea ice charts suggest the same may be happening this year.

Polar bears off Churchill_2000-11-20_wikipedia

Ice is forming along the Hudson Bay coast more than a week earlier than it was last year (barely discernible on the map below but detailed ice charts show it clearly), consistent with early build-up of ice in the Canadian Archipelago, East Greenland, and Foxe Basin since mid-September.

Sea ice Canada 2018 Oct 23

The question is: will the ice continue to build over the next few weeks or get blown offshore? See the ice charts below for this year and 2017.
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Scientific study finds polar bears excel at diving, contradicting previous expert opinion

A recent study by Norwegian biologist Karen Lone and colleagues, who tagged 57 polar bear females with sensors around Svalbard, discovered that polar bears can dive to a maximum depth of 13.9m and can swim long distances across open water without rest. Contrary to previous claims, polar bears are excellent divers and their breath-holding ability did not seem to limit how deep they could dive.

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From the abstract of the new paper by Lone and colleagues (Lone et al. 2018):

“Some bears undertook notable long-distance-swims. Dive depths up to 13.9 m were recorded, with dives ≥5 m being common. The considerable swimming and diving capacities of polar bears might provide them with tools to exploit aquatic environments previously not utilized.”

Compare the above statement to one made by Stirling and van Meurs (2015), after describing a 3 minute dive video-taped during an aquatic stalk of a bearded seal, also in the Svalbard area:

“…increased diving ability cannot evolve rapidly enough to compensate for the increasing difficulty of hunting seals because of the rapidly declining availability of sea ice during the open-water period resulting from climate warming.” [my bold]

These two papers really show the difference between using anecdotal accounts as if they were evidence of species-wide physical abilities and doing a scientific study on the physical ability of interest.

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New paper provides no evidence that polar bears ate whale carcasses to survive Eemian interglacial

Contrary to what the misleading press release implies, an entirely speculative new paper by polar bear specialists Kristin Laidre and Ian Stirling (among others) presents zero evidence that polar bear consumed whale carcasses during the last warm Interglacial (Eemian, ca. 115-130kya). And contrary to the impression that Eemian conditions were very challenging for polar bears, simulations from the single paleo sea ice simulation paper these authors cite show the ice-free season over most of the Eemian was less severe than today in the polar basin, with no reason for polar bears to scavenge extensively on large whale carcasses.

LaidreFEE_Wrangel Island scavenging_smaller

Polar bears are shown scavenging on the carcass of a dead bowhead whale that washed ashore on Wrangel Island, Russia. Credit: Chris Collins/Heritage Expeditions

This is yet another paper posing as science co-authored by Stirling that uses anecdotal accounts of behaviour to send a message about evolutionary capabilities of polar bears (Stirling and van Meurs 2015). With little or nothing to back it up, the paper’s real purpose is to convey Stirling’s opinion that past polar bear survival is irrelevant to understanding future polar bear survival — and that all the bears are gonna die unless we do something about carbon dioxide emissions generated by fossil fuel use.

Is it a coincidence that the Summary for Policy Makers was issued by the IPCC over the weekend (not the report with the science in it but the document that all politicians agreed were acceptable)? Look no further than the last sentence of National Geographic’s article on this story, which includes a quote from lead author Laidre and a link to the magazine’s interpretation of the new IPCC report:

“Laidre put it even more bluntly: “If you want polar bears around we need sea ice, and loss of sea ice closely tied to our activities and our fossil fuel emissions.” (Learn about the IPCC’s dire new climate report.)” 

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White Lie: Polar bear starvation is virtually never caused by sea ice loss

Starvation due to natural causes is the leading cause of death for polar bears and loss of body condition (getting thinner) is therefore the first symptom of impending death for virtually all polar bears that die naturally. However, polar bear specialist Andrew Derocher claims that loss of body condition is also the first symptom of climate change for polar bears.

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But how do you tell the difference between polar bears made thin by man-made climate change and those who are thin due to natural causes?

You can’t. Even a necropsy will not be conclusive because there are so many natural reasons for a bear to lose weight — and even starve to death — that’s it’s virtually impossible to say that any thin bear is skinny due to a lack of sea ice.

Emaciated polar bears like the one above from Somerset Island in the Canadian Arctic,1 captured on camera in August 2017, are being used to promote the idea that polar bears are already dying of starvation due to climate change. That’s a big white lie, as the headline above suggests: seven months later, National Geographic has admitted as much. Here I show why it could not have been true in the first place (with references from the scientific literature).

UPDATE: 29 August 2018: See my op-ed in the National Post (29 August 2018) and the GWPF video below on this issue:

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Before National Geographic apologized for hyping the starving polar bear video they exploited it to promote a message of doom

Back in early February this year, National Geographic used their “this is what climate change looks like” video to promote a newly-published polar bear study and endorse conservation activist Steven Amstrup’s debunked and abandoned prediction of polar bear catastrophe due to global warming. Even with this revelation, the starving polar bear video fiasco is not yet over.

Baffin Island starving pb headline_GlobalNews_8 Dec 2017

Polar Bears Really Are Starving Because of Global Warming, Study Shows (National Geographic, 1 February 2018).

The initial focus of the February 2018 National Geographic article was a study published that week by Anthony Pagano and colleagues (Pagano et al. 2018; Whiteman 2018), suggesting that a few polar bears in the Southern Beaufort Sea were not getting enough to eat in early spring from 2014-2016 (with no reference to sea ice conditions; see my critique of that study here).

Then, Steven Amstrup, spokesman for activist organization Polar Bears International, is quoted as saying (my bold):

“If these results hold up [from Pagano’s study], then it shows that the loss of sea ice may have a bigger impact on the bears than previously thought, said Amstrup, a former USGS polar bear expert. Amstrup’s own 2010 study projected that continued decline in sea ice would reduce the global population of bears by two thirds, to less than 10,000 by 2050.

Seriously, no one except Amstrup and his Polar Bears International fanbase are citing his outlandish 2010 prediction, which is just a rehash of his 2007 USGS internal report and its 2008 journal version (Amstrup 2007, 2008, 2010). Amstrup’s prediction is not only a failure (Crockford 2017, 2018; Crockford and Geist 2018) but it’s been abandoned by his colleagues for vaguer or more moderate predictions of population decline (e.g. Atwood et al. 2015, 2016; Regehr et al. 2016).

National Geographic has now apologized for saying that the emaciated bear in the SeaLegacy video they so heavily promoted was “what climate change looks like” (and replaced the caption with “this is what starvation looks like,” even though there is no evidence the bear was starving from lack of food rather than from severe illness).

But the damage is done. By endorsing the discredited polar bear survival predictions of Amstrup along with the video, National Geographic degraded itself even further in the eyes of rational and informed readers. I’ll have more to say on the SeaLegacy video exploited by National Geographic and its message that starving polar bears are victims of climate change in a subsequent post: we haven’t yet reached the end of this debacle.

References

Amstrup, S.C., Marcot, B.G. & Douglas, D.C. 2007. Forecasting the rangewide status of polar bears at selected times in the 21st century. US Geological Survey. Reston, VA. Pdf here

Amstrup, S.C., Marcot, B.G., Douglas, D.C. 2008. A Bayesian network modeling approach to forecasting the 21st century worldwide status of polar bears. Pgs. 213-268 in Arctic Sea Ice Decline: Observations, Projections, Mechanisms, and Implications, E.T. DeWeaver, C.M. Bitz, and L.B. Tremblay (eds.). Geophysical Monograph 180. American Geophysical Union, Washington, D.C. http://onlinelibrary.wiley.com/doi/10.1029/180GM14/summary and http://alaska.usgs.gov/science/biology/polar_bears/pubs.html

Atwood, T.C., Marcot, B.G., Douglas,D.C., Amstrup, S.C., Rode, K.D., Durner, G.M. and Bromaghin, J.F. 2015. Evaluating and ranking threats to the long-term persistence of polar bears. USGS Open-File Report 2014–1254. Pdf here.

Atwood, T.C., Marcot, B.G., Douglas, D.C., Amstrup, S.C., Rode, K.D., Durner, G.M. et al. 2016. Forecasting the relative influence of environmental and anthropogenic stressors on polar bears. Ecosphere, 7(6), e01370.

Crockford, S.J. 2017. Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus). PeerJ Preprints 2 March 2017. Doi: 10.7287/peerj.preprints.2737v3 Open access. https://doi.org/10.7287/peerj.preprints.2737v3

Crockford, S.J. 2018. State of the Polar Bear Report 2017. Global Warming Policy Foundation Report #29. London. pdf here.

Crockford, S.J. and Geist, V. 2018. Conservation Fiasco. Range Magazine, Winter 2017/2018, pg. 26-27. Pdf here.

Pagano, A.M., Durner, G.M., Rode, K.D., Atwood, T.C., Atkinson, S.N., Peacock, E., Costa, D.P., Owen, M.A. and Williams, T.M. 2018. High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear. Science 359 (6375): 568 DOI: 10.1126/science.aan8677

Whiteman, J.P. 2018. Out of balance in the Arctic. Science 359 (6375):514-515. http://science.sciencemag.org/content/359/6375/514

Sea ice silly season: Wadhams spouts fake facts about polar bears of northern Greenland

As the seasonal minimum for Arctic sea ice approaches, the media get carried away by hyperbole. Tha’t been true since 2007. This year, other outlets will need to work hard to beat yesterday’s bit of nonsense from The Independent trying to out-do The Guardian: it not only includes false polar bear facts (from sea ice researcher Peter Wadhams) but leads with last year’s controversial SeaLegacy video of an emaciated polar bear. Sea ice silly season has truly begun.

East Greenland Scorsby Sound March 2011 on Kap Tobin_Rune Dietz_press photo

Wadhams (described as “one of the UK’s leading sea ice scientists” although not a particularly respected one) was interviewed about the small area of open water that opened up over the last few days in northern Greenland (see NSIDC photo below), driven by offshore winds (not melt). This region is the eastern-most part of the area that is considered the “last holdout” for Arctic sea ice: an immense band of very thick (4-20m) multiyear ice that stretches across the Arctic Ocean shores of the Canadian Arctic Archipelago.

The open water is expected to last a few days at most but Wadhams was absolutely breathless with dire warnings of what this might mean for the future of polar bear in the region (about which he knows nothing), rhetoric ramped up even further by the news outlet with quotes from co-director of the Grantham Institute (London), Martin Siegert, and predictions on how low the sea ice minimum might be.

Greenland north open water_13 Aug 2018 NASA_NSIDC 15 Aug 2018 report

Cape Morris Jesup on 13 August 2018. W. Meier, NSIDC/NASA.

I think this is a truly spectacular example of the ignorance of scientists speaking outside their area of expertise used to mislead the public but decide for yourself.

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