The newest polar bear science paper making the rounds courtesy the US Geological Survey, is a perfect example of a statistically-significant result with no biological significance. While the results are rather lame, the paper is dangerous because it repeats the disingenuous claim (see Crockford 2017) that Southern Beaufort Sea polar bear numbers declined in recent years due to summer sea ice loss.
The USGS authors (Durner et al. 2017) know this harm-from-summer-ice-loss assertion is not true for the Southern Beaufort subpopulation but the more papers they can get into print that say so, the more likely it will be believed — and the less likely readers will check older literature that documents the recent decline in polar bear numbers was due to a three year period (2004-2006) when thick ice conditions in spring made seal hunting a challenge, a repeat of a well-known phenomenon (e.g. Stirling et al. 1980; Stirling 2002) unique to this region that has been documented since the 1960s.
The Durner paper (USGS press release “Increased Sea Ice Drift Puts Polar Bears on Faster Moving Treadmill” published online 6 June ahead of print) spins the research results as potentially significant bad news but in so doing reveals how desperate they have become to make the public and their biology colleagues believe that Southern Beaufort polar bears, among others, are being negatively affected by summer sea ice loss (as per Stirling and Derocher 2012).
Durner, G.M., Douglas, D.C., Albeke, S.E., Whiteman, J.P., Amstrup, S.C., Richardson, E., Wilson, R.R. and Ben-David, M. 2017. Increased Arctic sea ice drift alters adult female polar bear movements and energetics. Global Change Biology. DOI: 10.1111/gcb.13746 http://onlinelibrary.wiley.com/doi/10.1111/gcb.13746/abstract [paywalled]
In fact, the Durner et al. paper does not document any harm to polar bears from the proposed ‘treadmill’ effect of more rapidly moving ice for the period 1999-2013 compared to 1987-1998, but instead uses models to suggest bears might have to eat one to three more seals per year to compensate for the extra energy needed to walk against the moving ice. That’s right: perhaps only 1 more seal per year out of the 50 or so they would usually consume (see Stirling and Øritsland 1995). In my opinion, that’s a pretty lame result for what one of the co-authors described as an immense amount of work.
News outlets have essentially used the USGS press release as a click-bait lede for another round of Trump-bashing with respect to the Paris climate change agreement, see here and here: the stories are hardly about polar bears at all. And predictably, polar bear activist and co-author Steven Amstrup (paid spokesperson for Polar Bears International, famous for their “Save Our Sea Ice” campaign) appears to be using the same approach: an up-coming call-in talk radio program at NPR’s Anchorage affiliate KSKA for Tuesday 13 June at 10:00 (Alaska time, see “Talk of Alaska”) is being billed as a discussion of “polar bears, climate change, and the Paris Accord” (h/t AK geologist). Continue reading
Posted in Advocacy, Conservation Status, Life History, Sea ice habitat
Tagged Alaska, Amstrup, Durner, endangered, energy, loss of summer ice, moving sea ice, polar bear, population decline, sea ice, seals, Southern Beaufort, spring feeding, summer sea ice, thick spring ice, threatened, treadmill, USGS
This new effort by the BBC would make the PR department of the Center for Biological Diversity proud, with it’s prominent use of animal tragedy porn pretending to be science. In contrast, the actual science shows something quite different: though summer sea ice since 2007 has declined to levels not predicted until 2040-2070, there has been virtually no negative impact on polar bear health or survival, a result no one predicted back in 2005.
Bizarrely entitled “A 3-million-year ice age is coming to an end“ (15 September 2016), this slick video pretends it’s promoting the recently released paper by Harry Stern and Kristen Laidre (2016) that got a lot of media attention last week (see here and here).
Who exactly suggested the profound prophesy stated in their chosen title, the BBC Earth folks don’t say: the Stern and Laidre paper certainly does not. And the use of a bear that appears to drown before our eyes is Hollywood-style emotional manipulation. Note the careful use of “might” (above) and “could” (below).
Watch the videos below and weep not for the plight of the polar bear, but for the downfall of science journalism. Continue reading
Posted in Sea ice habitat
Tagged Arctic, BBC, Center for Biological Diversity, declining sea ice, endangered, facts, Laidre, polar bear, sea ice, Stern, summer sea ice, terminal threat, threatened, tragedy porn, video
According to sea ice experts, winter sea ice habitat for polar bears is not expected to decline at all by 2050 and the critical spring sea ice that polar bears need for gorging on young seals and for mating is not predicted to change much (Durner et al. 2007, 2009), which is why computer modelled predictions about the dire future for polar bears only assessed the potential future effects of declining summer sea ice (e.g. Amstrup et al. 2007; Stirling and Derocher 2012). Note spring is April-June.
See if that fact is clear in the interview responses by out-spoken polar bear biologists that has just been published in the polar bear portion (“Beyond the polar bear”) of this year’s University of Alberta magazine spring climate change feature. If you can get past the “canaries in the coal mine” opener…
Posted in Advocacy, Sea ice habitat
Tagged advocacy, Derocher, facts, interview, polar bear, predictions, sea ice, spring sea ice, starving polar bears, Stirling, summer sea ice
You may or may not have noticed that even though Chukchi Sea ice coverage has been way below average this melt season, there has been no hue-and-cry about poor suffering Chukchi polar bears. That’s because polar bear biologist’s own research has shown that the health and survival of these bears has not been negatively impacted by low summer sea ice. There may be threats from poaching in Russia, but not lack of summer sea ice.
As of this date, developing sea ice is only just approaching Wrangel Island, a major polar bear denning region in the Chukchi Sea, see maps below (Ovsyanikov 2006).
Yet, polar bear specialists insist that neighbouring Beaufort Sea bears – who endure a much shorter open-water season – are in peril of extinction because of scarce summer sea ice.
Despite the public outcry last week over future polar bear survival, the polar-bears-are-doomed crowd can’t hide the fact that this year, spring sea ice habitat for polar bears worldwide has been excellent.
This year on 19 July, for example, Hudson Bay had greater than 150,000 square km more sea ice than there was in 2009 on that date (526.2 vs. 368.5 mkm2)(1992 was a particularly cold year and most bears left the ice as late in 2009 as they did in 1992).1 Conditions have also been excellent for pregnant females around Svalbard – Norwegian polar bear researchers recently reported a good crop of cubs this spring.
Worldwide, there was exactly the same amount of Arctic sea ice present on 18 July 2015 as there was back in 2006 (Day 199) – 8.4 mkm2. By 19 July (day 200), 2015 had more ice than 2006 (8.4 mkm2 vs. 8.3).
All this means that recent summer ice melt has not impinged on the spring feeding period that is so critically important for polar bears. So much ice left in early summer means there was lots of sea ice in the spring (April-June), even in the Southern Beaufort Sea.
The only region with sea ice coverage well below the last five years is the Chukchi Sea (see plots below, click to enlarge). So why aren’t we hearing the-sky-is-falling stories about Chukchi bears? Because biologist have already demonstrated that polar bears in the Chukchi do very well even with no summer sea ice.
Posted in Life History, Sea ice habitat
Tagged Chukchi Sea, Derocher, habitat, Hudson Bay, melt ponds, polar bear, polar bear science, sea ice, Southern Beaufort, spring ice conditions, summer sea ice, Svalbard, thick spring ice, tracking polar bears, walking hibernation
The yearly sea ice minimum extent is almost upon us, which has recently been the seasonal signal for excitable biologists and their activist groupies to resume their breathless rants about what sea ice loss could mean for polar bears.
Never mind that the summer minimum extent reached in September, no matter how low it goes, is pretty much irrelevant to polar bear health and survival. As I’ve discussed before, what’s really important is the presence of not-too-thick ice during the spring, so they can catch lots of young seals and put on lots of fat.
But to a lesser degree, the extent at mid-to-late summer is important because this is when pregnant females that prefer to make their maternity dens on shore are looking for good places to spend the winter.
So the topic for today is this: how much does the extent of ice at the height of summer dictate where polar bear females make their winter dens?
Posted in Life History, Sea ice habitat
Tagged Arctic ice death spiral, Arctic ice extent, Barents Sea, CIS, denning females, Labrador, Mark Serreze, NSIDC, polar bear, Southern Beaufort, summer sea ice, summer sea ice minimum, tracking polar bears, USGS, western hudson bay
Ah, that never-ending treadmill of meal preparation and cleanup. You might be surprised to find out that polar bears do it too.
Figure 1. How do polar bears look so clean most of the time when they get this bloody on a regular basis? They wash up!
I found an interesting description of polar bears washing during and after feeding, by a young Ian Stirling in one of his earliest published polar bear papers (Stirling 1974). At the time, he was observing polar bears on southwest Devon Island (74°43′ N; 91°10′ W, see Fig. 2 below) between 24 July and 8 August 1973.
Even today, there’s ice for hunting seals in mid-to-late-summer in that part of Canada (Fig. 3).
Posted in Life History
Tagged 1973, Canadian Arctic, Devon Island, eating seals, feeding, polar bear, polar bears in summer, sea ice extent, Stirling, summer sea ice, washing
As if on cue just before an important polar bear announcement, Steven Amstrup, full time employee of Polar Bears International (PBI), is crying “starving polar bears” yet again, with a laughable twist.
Over at “The Conversation” (a university supported forum for academics), in a piece titled “Cold weather in the US no solace for starving polar bears,” Amstrup uses his adjunct affiliation at University of Wyoming to unleash a bit of unpaid advertising for PBI’s alarmist message (I put it this way because while Amstrup does disclose his affiliation at PBI, he is more than just an affiliated member, he is their paid spokesperson).
Ironically, the headline photo (Fig. 1) is the notorious “Ursus bogus,” the photoshopped image used by the journal Science back in May 2010 to feature an article on the integrity of science, It was quickly exposed by Tim Blair at The Telegraph (also covered at WUWT), and the journal was obliged to acknowledge the error, replace the image and issue a correction.
In this case, commenter Brad Keyes at The Conversation defends the use of the “Ursus bogus” image with this astonishing statement [UPDATE Jan. 25/14: it has since transpired that this was almost certainly meant to be satire]:
“The problem is, only sensational exaggeration makes the kind of story that will get politicians’—and readers’—attention. So, yes, climate scientists might exaggerate, but in today’s world, this is the only way to assure any political action and thus more federal financing to reduce the scientific uncertainty.”
However, we now know that Amstrup is crying wolf — summer sea ice has been declining despite a hiatus in global warming and unusual numbers of polar bears are not starving. He seems to think that if he keeps repeating his Chicken Little message (with nary a recent photo of an actual starving polar bear) he will convince more people to believe him and donate to PBI. It’s his job to do so of course, so he’s not likely to stop. [pardon my mixed metaphor – Amstrup, if you recall, prefers a Titanic metaphor]
Posted in Advocacy, Conservation Status, Sea ice habitat
Tagged Amstrup, extinction, global warming, hiatus, Polar Bears International, sea ice decline, starving polar bears, summer sea ice, threatened, Ursus bogus
Here is the follow-up to my post on the July track map for polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice. See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here).
The track map for September was posted on the USGS website on October 17 (delayed due to the US government shutdown) and is copied here below (Figure 1). The ice rebounded during the second half of the month (after the annual minimum was reached on September 13). The ten bears from July were down to eight – their collars might have stopped working or fallen off (most likely), they might have left the area entirely (also possible) or they might have died (the researchers don’t say which).
Figure 1. Original caption: “Movements of 8 satellite-tagged polar bears for the month of September, 2013. Polar bears were tagged in 2013 on the spring-time sea ice of the southern Beaufort Sea. All 8 of these bears have satellite collar transmitters [i.e., all are females]. Polar bear satellite telemetry data are shown with Ice Analysis charts from 26 August, 2013. Ice Analysis charts are made available by the National Ice Center. The land cover is made available by Natural Earth. Click on the above image to enlarge.” [Note that the dots with the polar bear icons are the end points (end September), while the other end of the string is their position in early September, indicating that the ice is now moving towards the shore. The pink dot present in August is almost entirely obscured by the purple dot, which is overlapping the yellow dot on shore in Alaska; also, the light brown dot is on Banks Island, far right.]
It appears that of the eight polar bears still being followed by USGS researchers in September, four are on shore and four are still on the ice.
Only time will tell if the four females on shore are pregnant and preparing maternity dens for the winter, but this seems the likely reason they are not on the ice with the others.
One very interesting point worth noting:
the one bear (light brown) captured onshore in the Southern Beaufort
subpopulation region in the spring of 2013
, has moved into the Northern Beaufort
subpopulation region, on Banks Island (see map here
), and may be denning there. This inter-subpopulation movement is relatively uncommon.
The map for July 2013 is below, for comparison: Continue reading
Posted in Life History, Sea ice habitat
Tagged Beaufort Sea, denning females, Eastern Beaufort, females with radio collars, habitat, Northern Beaufort, polar bears, sea ice extent, Southern Beaufort, summer ice minimum, summer sea ice, tracking polar bears, tracking polar bears by satellite, USGS
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).
Posted in Conservation Status, Life History, Sea ice habitat
Tagged annual summer minimum, arctic sea ice, Beaufort Sea, body condition, Cherry, Chukchi, declining sea ice, Eastern Beaufort, good news, heavy sea ice, Hudson Bay, ice-free Arctic, litter size, loss of summer ice, Pilfold, polar bear, record low, Regehr, ringed seals, Rode, sea ice extent, Southern Beaufort, Stirling, summer ice minimum, summer sea ice, thick spring ice