Tag Archives: Stirling

Human-polar bear conflicts: Stirling 1974 vs. Amstrup 2013

Posted on November 17, 2013 | Comments Off on Human-polar bear conflicts: Stirling 1974 vs. Amstrup 2013

What a difference a few decades makes to attitudes about human-polar bear conflicts:

Ian Stirling, 1974:

“Dr. Stirling felt that complete cessation of hunting, such as exists in Norway, may increase bear-man conflicts. Dr. Reimers replied that the careful harvesting of polar bears was probably desirable, but the total ban now in effect was largely an emotional and political decision rather than a biological one. Last year four bears were killed in self-defense.” [my bold]
(1974 PBSG meeting “Norway – progress reported by [Thor] Larsen”; Anonymous 1976:11).

Stephen Amstrup, 2013:

“We have predicted in no uncertain times [sic – terms?] that as bears become hungrier as the sea ice absence period is longer, more and more of these animals are going to be venturing into communities, venturing into villages, raiding food caches, getting into garbage, and even attacking people. So we predict these kinds of events are going to be more frequent and more severe because of climate change.” [my bold]
(The Guardian, November 4, 2013).

Continue reading

Comments Off on Human-polar bear conflicts: Stirling 1974 vs. Amstrup 2013

Posted in Advocacy, Cannibalism, Polar bear attacks

Tagged , , , , , , , , , ,

Lancaster Sound – a rarely-mentioned region with a large polar bear population

Posted on October 27, 2013 | Comments Off on 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.

Continue reading

Comments Off on Lancaster Sound – a rarely-mentioned region with a large polar bear population

Posted in Conservation Status, Population, Sea ice habitat

Tagged , , , , , , , , , , , , , , , , , , , , , ,

Record sea ice loss in 2007 had no effect on polar bears, Chukchi study confirms

Posted on September 15, 2013 | Comments Off on Record sea ice loss in 2007 had no effect on polar bears, Chukchi study confirms

One aspect of the recently published study on Chukchi Sea polar bears (Rode et al.2014 [now in print] 2013; see here and here) has not been stressed enough: their finding that the differences in overall condition between bears in the Chukchi and Southern Beaufort Seas came down to disparities in spring feeding opportunities and therefore, the condition of spring sea ice.

The fact that spring — not summer — is the most critical period for polar bears is something I’ve pointed out before (see here and here, for example) but it’s worth repeating at this time of year, when all eyes are on the annual ice minimum. It is often treated as a given that the decline in extent of summer sea ice in the Arctic since 1979 has been detrimental to polar bears. However, this is an assumption that we can now say is not supported by scientific evidence (see summary of that evidence here).

The results published by Rode et al. (2014 2013) not only add further support to the conclusion that declines in summer sea ice have not harmed polar bears, but should put the matter to rest – unless new evidence to the contrary is produced.

Chukchi bears, the report tells us, had more food available in the spring than Southern Beaufort bears (see map below) and this was the primary reason that bears were doing very well in the Chukchi and not quite as well in the Southern Beaufort. And because the polar bears for this study were captured and measured in mid-March to early May, from 2008 to 2011, they reflect spring-time conditions for 2008-2011 as well as year-round conditions from 2007 through 2010.

This means that the annual low ice extent for 2007 (record-breaking at the time), in the fall before this study began, had no discernible negative effect on either Chukchi or Southern Beaufort polar bears – and neither did similarly low annual minimums in two of the three remaining years of the study (Fig 1).

Figure 1. Sea ice extent at August 27, 2007 – the lowest extent that year (downloaded September 15, 2013 from IARC-JAXA, Arctic Sea-ice Monitor). At the time, it was the lowest extent recorded since 1979 (2012 broke that record). This (2007) was the fall before the Rode & Regehr study on Chukchi/Southern Beaufort polar bears began (2008-2011). The ice was almost as low in September 2008 and 2010, while 2009 was more like 2013.

Figure 1. Sea ice extent at August 27, 2007 – the lowest extent that year (downloaded September 15, 2013 from IARC-JAXA, Arctic Sea-ice Monitor). At the time, it was the lowest extent recorded since 1979 (2012 broke that record). This (2007) was the fall before the Rode & Regehr study on Chukchi/Southern Beaufort polar bears began (2008-2011). The ice was almost as low in 2008 and 2010, while 2009 was more like 2013.

Continue reading

Comments Off on Record sea ice loss in 2007 had no effect on polar bears, Chukchi study confirms

Posted in Conservation Status, Life History, Sea ice habitat

Tagged , , , , , , , , , , , , , , , , , , , , , , , , ,

Polar bears have not been harmed by sea ice declines in summer – the evidence

Posted on August 18, 2013 | Comments Off on Polar bears have not been harmed by sea ice declines in summer – the evidence

PB logo colouredThe polar bear biologists and professional activists of the IUCN Polar Bear Specialist Group (PBSG) continue to insist that since 1979 increasingly smaller amounts of Arctic sea ice left at the end of summer (the September ice minimum) have already caused harm to polar bears. They contend that global warming due to CO2 from fossil fuels (“climate warming” in their lexicon) is the cause of this decline in summer ice.

In a recent (2012) paper published in the journal Global Change Biology (“Effects of climate warming on polar bears: a review of the evidence”), long-time Canadian PBSG  members Ian Stirling and Andrew Derocher (both of University of Alberta) summarized their position this way:

“Climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze-up. We summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (Ursus maritimus), negatively affects their long-term survival”

I’ve spent the last year examining their evidence of on-going harm, but in addition, I’ve looked at the evidence (much of it not mentioned in the Stirling and Derocher paper1) that polar bears have either not been harmed by less sea ice in summer or have thrived in spite of it.

This is a summary of my findings. I’ve provided links to my original essays on individual topics, which are fully referenced and illustrated. You are encouraged to consult them for complete details. This synopsis (pdf with links preserved, updated; pdf with links as footnotes, updated) complements and updates a previous summary, “Ten good reasons not to worry about polar bears” (pdf with links preserved; pdf with a foreword by Dr. Matt Ridley, with links as footnotes).

Update 8 September 2013: to include links to my post on the recently published Chukchi population report; updated pdfs have been added above.

Update 22 January 2014: added figure comparing March vs. September sea ice extent using the same scale, from NOAA’s “2014 Arctic Report Card,” discussed here.
Continue reading

Comments Off on Polar bears have not been harmed by sea ice declines in summer – the evidence

Posted in Conservation Status, Population, Sea ice habitat, Summary

Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Ian Stirling’s howler update: contradicted by scientific data

Posted on August 11, 2013 | Comments Off on Ian Stirling’s howler update: contradicted by scientific data

Following up on my last post (Ian Stirling’s latest howler: “the polar bear who died of climate change”), I tracked down some details contained in the original Norwegian news report but which were left out of the articles that spread the story around the world. I also found some pertinent research posted online that appears to be the work of the researchers who captured this bear in April.

Figure 1. The Norwegian newpaper, The Local (Aug. 7, 2013), identifies the location that the bear was found as “a small island near Texas Bar” (marked by the square on the above map) in the very north of Spitsbergen and states it was found on July 7 – details other reports did not bother to include. To have been 250km south of that position in April (when he was tagged), he must have left the ice near the southern tip of Spitsbergen when there was still lots of ice further north.

Figure 1. The Norwegian newspaper, The Local (Aug. 7, 2013), says the bear was found on “a small island near Texas Bar” (marked by the square on the above map) in the very north of Spitsbergen, and states it was found on July 7 – details other reports did not bother to include. [“Texas Bar” is a hut built by a Norwegian hunter in 1927]. To have been 250km south of that position in April (when he was tagged), he must have left the ice near the southern tip of Spitsbergen when there was still lots of ice further north.


Continue reading

Comments Off on Ian Stirling’s howler update: contradicted by scientific data

Posted in Advocacy, Life History, Sea ice habitat

Tagged , , , , , , , , , , , , , , ,

Ian Stirling’s latest howler: “the polar bear who died of climate change”

Posted on August 7, 2013 | Comments Off on Ian Stirling’s latest howler: “the polar bear who died of climate change”

Will wildlife biologist and Polar Bear Specialist Group member Ian Stirling now say anything – no matter how unscientific – to garner more sympathy and media attention for polar bears? It appears so.  [see followup post published Aug. 11, here]

A tabloid-style picture-is-worth-a-thousand-words article appeared in the environment section of the UK newspaper The Guardian yesterday (August 6, 2013) with a picture of a dead polar bear meant to wring your heart. The picture is a vehicle for statements from Ian Stirling and others that this polar bear died from climate change. A longer article was alongside.

The caption below the photo of a dead polar bear (animal tragedy porn) is this:

“This 16-year-old male polar bear died of starvation resulting from the lack of ice on which to hunt seals, according to Dr Ian Stirling.”

Many folks have been asking questions about this and so have I.

I suggest this is what really happened: the polar bear biologists working in Svalbard earlier this year knew this bear was going to die back in April when they captured him – they simply waited, with a photographer on hand, until he died. It was an orchestrated photo-op.

[Update, Aug. 8, 2013: I suggest it was not necessary for anything more to happen to “orchestrate” this photo than for the researchers who captured the bear in April to tell colleagues and local tour boat operators (who always have avid photographers on board) to “keep an eye out for a dead bear, we don’t think this guy is going to make it.” However, very little real information is provided. Who knows when (or from whom) we’ll get the whole story — if ever? That’s why anecdotal accounts like these aren’t “evidence” of anything, in the scientific sense. That’s the real take-home message here.  If this dead bear was being presented as scientific evidence, we’d have been given all the details, including necropsy results, local ice conditions, precise dates, locations, and photos of any other bears that were seen that were in poor condition. In other words, a proper scientific report. ]

Continue reading →

Comments Off on Ian Stirling’s latest howler: “the polar bear who died of climate change”

Posted in Advocacy, Sea ice habitat

Tagged , , , , , , , , , , , , , , , , ,

Biologists spreading misinformation: hybridization with grizzlies not due to polar bears moving inland

Posted on August 3, 2013 | Comments Off on Biologists spreading misinformation: hybridization with grizzlies not due to polar bears moving inland

A paper published last week in the journal Science, written by a team of biologists and atmospheric scientists, expounds on a possible dire future for a range of Arctic animals. It’s called, “Ecological consequences of sea-ice decline” and surprisingly, polar bears are discussed only briefly.

However, with the inclusion of one short sentence, the paper manages to perpetuate misinformation on grizzly/polar bear hybridization that first appeared in a commentary essay three years ago in Nature  (Kelly et al. 2010)1. The Post et al. 2013 missive contains this astonishing statement (repeated by a Canadian Press news report):

“Hybridization between polar bears and grizzly bears may be the result of increasing inland presence of polar bears as a result of a prolonged ice-free season.”

Lead author of the paper, Professor of Biology Eric Post, is quoted extensively in the press release issued by his employer (Penn State University, pdf here). In it, Post re-states the above sentence in simpler terms, removing any doubt of its intended interpretation:

“… polar and grizzly bears already have been observed to have hybridized because polar bears now are spending more time on land, where they have contact with grizzlies.”

Both statements are patently false. All recent hybridization events documented (2006-2013) occurred because a few male grizzlies traveled over the sea ice into polar bear territory and found themselves a polar bear female to impregnate (see news items here and here, Fig. 1 below). These events did not occur on land during the ice-free season (which is late summer/early fall), but on the sea ice in spring (March-May).

Grizzlies have been documented wandering over the sea ice of the western Arctic since at least 1885 (Doupe et al. 2007; Fig. 2, below) and the presence in this region of hybrid grizzly/polar bear offspring is not an indicator of declining summer sea ice, whether due to global warming or natural causes, or some combination thereof.

Continue reading

Comments Off on Biologists spreading misinformation: hybridization with grizzlies not due to polar bears moving inland

Posted in Advocacy, Hybridization, Life History, Sea ice habitat

Tagged , , , , , , , , , , , , , , , , ,

Southern Hudson Bay subpopulation status, farthest south of all polar bears

Posted on July 25, 2013 | Comments Off on Southern Hudson Bay subpopulation status, farthest south of all polar bears

“The Arctic” is a bit hard to define. While the Arctic Circle works as a good boundary for some purposes and the 100C isotherm for July for others, neither work for polar bears because several subpopulations live well south of these limits (Fig. 1).

In the east, Western Hudson Bay, Southern Hudson Bay and Davis Strait are all located well south of the Arctic Circle and the first two (and half of Davis Strait) are beyond the 100C July isotherm as well. In the western Arctic, the Chukchi Sea subpopulation is within the 100C July isotherm but at least half of its bears reside south of the Arctic Circle (Fig. 1) in the Bering Sea (see previous post here).

Unique amongst all of these is Southern Hudson Bay – all of its polar bears make maternity dens and/or spend the summer south of 600N.

Southern Hudson Bay (SH) bears live in the Canadian provinces of Ontario, while Western Hudson Bay (WH) bears reside in Manitoba and Nunavut. The two groups mix over the winter but appear to spend the summer/fall in their respective regions (Stirling et al. 2004). [See previous posts on Western Hudson Bay bears here, here, and here]

“Further south” in the Arctic usually means warmer, with open water present more weeks every summer, sea ice for fewer weeks over the winter. So, shouldn’t the bears of Southern Hudson Bay be already suffering more harm from global warming than virtually all other subpopulations, including those in Western Hudson Bay?

After all, Western Hudson Bay bears appear to have experienced a statistically significant decline in numbers, among other effects (Regehr et al. 2007; Stirling and Derocher 2012) — surely Southern Hudson Bay bears are doing worse?

You’d think so, but they aren’t.

Figure 1. Boundary limits for “the Arctic” (top map) such as the Arctic Circle (dashed line) or the 100C isotherm for July (solid red line) would not include several polar bear subpopulations that live south of these.

Figure 1. Boundary limits for “the Arctic” (top map) such as the Arctic Circle (dashed line) or the 100C isotherm for July (solid red line) would not include several polar bear subpopulations that live south of these.

UPDATED October 28, 2014: Reference added, Obbard et al. 2013 (aerial survey results).
Continue reading

Comments Off on Southern Hudson Bay subpopulation status, farthest south of all polar bears

Posted in Conservation Status, Population, Sea ice habitat

Tagged , , , , , , , , , , , , , ,

Chukchi polar bear status contradicts the “message” – new details

Posted on July 7, 2013 | Comments Off on Chukchi polar bear status contradicts the “message” – new details

Previously, I summarized preliminary results of polar bear research in the Chukchi Sea undertaken between 2008 and 2011 by US Fish & Wildlife biologist Eric Regehr and US Geological Survey researcher Karyn Rode. At the time, a peer-reviewed paper on this study was promised shortly.

It now appears this paper is indeed on the way. I’m sure of that because a few weeks ago, I came across a conference presentation given by Karyn Rode that is a summary of the upcoming Chukchi research paper. The title of both presentation and ‘in review’ paper is:

“Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations.”

Rode’s slide presentation (given at the annual Lowell Wakefield Fisheries Symposium at the end of March, in Anchorage, Alaska) was posted online by the symposium organizers. It provides some very interesting details on the status of Chukchi Sea bears compared to bears in the Southern Beaufort, and contains some mighty “inconvenient” conclusions that should raise some eyebrows.

I’ve summarized these details and conclusions below in point form, below the maps.

Figure 1. Chukchi and Beaufort Seas (from Wikipedia), upper. ‘Chukchi Sea’ polar bears are shared between the USA and Russia; ‘Southern Beaufort’ bears are shared between the US and Canada, lower (from PBSG, with labels added). Pink dots are the subpopulations featured in the Rode et al. presentation and upcoming paper.

Figure 1. Chukchi and Beaufort Seas (from Wikipedia), upper. ‘Chukchi Sea’ polar bears are shared between the USA and Russia; ‘Southern Beaufort’ bears are shared between the US and Canada, lower (from PBSG, with labels added). Pink dots are the subpopulations featured in the Rode et al. presentation and upcoming paper.

Continue reading

Comments Off on Chukchi polar bear status contradicts the “message” – new details

Posted in Conservation Status, Sea ice habitat

Tagged , , , , , , , , , , , , , , ,

Great polar bear red herring in the Southern Beaufort

Posted on July 4, 2013 | Comments Off on Great polar bear red herring in the Southern Beaufort

Red herring iconWe know that thick-ice springs occurred in 1974, 1975, 1986, 1992, 2004, and 2005 in the former ‘Eastern Beaufort’ – now the southern portion of the ‘Northern Beaufort’ and the eastern portion of the ‘Southern Beaufort.’ We know that these severe spring ice conditions negatively impacted both polar bears and ringed seals in this region every decade since the 1960s because the effects have been documented by numerous studies conducted in April through May for polar bears (Amstrup et al. 2006; Cherry et al. 2009; Pilfold et al. 2012; Stirling 2002; Stirling and Lunn 1997; Stirling et al. 1980; Stirling et al. 1993; Stirling et al. 2008) and in June and July for ringed seals (Harwood et al. 2012; Smith 1987), see previous posts here, here, and here.

For example, even though Ian Stirling and colleagues argued in their 2008 paper that the thick spring ice conditions in 2004, 2005 and 2006 (but not those in previous decades) were caused by storms initiated or intensified by greater amounts of open water in previous summers, they did not deny that the thick-ice springs occurred. They stated quite clearly that:

“The 1960s, 1970s, and 1980s each experienced a two- to three-year decline in seal productivity in the eastern Beaufort Sea and Amundsen Gulf, associated with heavy ice conditions, around mid-decade. Each was followed by a decline in polar bear reproduction and condition, after which both seal and bear populations recovered (Smith, 1987; Harwood et al., 2000; Stirling, 2002). The beginning of each of those three periods was associated with heavy ice conditions through the winter before the reproductive decline of the seals, followed by a late spring breakup.” [my bold]

So, I have to say, I was shocked but not surprised to find that in the more recent scientific literature, the phenomenon of thick-ice springs every decade in Southern and Northern Beaufort has been deliberately ‘disappeared.’ 

Not surprised because I suspected it had happened — this issue was a feature of the Stirling and Derocher (2012) paper from late last year which was the topic of my very first blog post, “Cooling the polar bear spin.”

However, I think it is important to document how the transmogrification of sea ice effects on polar bears was managed in the scientific literature so that everyone can see exactly what has been done. In a truly astonishing move for what is supposed to be a field of science, thick-ice springs have been effectively replaced by an open-water red herring as the scourge of Southern Beaufort polar bears.

Continue reading

Comments Off on Great polar bear red herring in the Southern Beaufort

Posted in Advocacy, Conservation Status, Sea ice habitat

Tagged , , , , , , , , , , , , , ,